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Effects of Fasting & Time Restricted Eating on Fat Loss & Health | Huberman Lab Podcast #41



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Welcome to the Huberman Lab Podcast,
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where we discuss science and science-based tools
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for everyday life.
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I'm Andrew Huberman,
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and I'm a professor of neurobiology and ophthalmology
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at Stanford School of Medicine.
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Today, we're talking all about fasting.
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And anytime we're talking about fasting,
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we are also talking about eating
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because we all need to eat sooner or later.
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We're going to talk about how fasting and when we eat
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influences a large range of aspects of our health
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and wellbeing, both physical and mental.
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So while nowadays,
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most people are familiar with the term intermittent fasting,
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also sometimes called time-restricted feeding,
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I think most people don't really understand
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how that process works.
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It's sort of obvious that intermittent fasting,
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AKA time-restricted feeding,
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involves eating at certain periods of each 24-hour cycle,
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or maybe even not eating for entire days in some cases.
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But if you think about it, everybody sleeps eventually.
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And therefore, because people don't eat during their sleep,
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almost everybody is employing some form
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of intermittent fasting or time-restricted feeding.
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What we're going to talk about today
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is how particular schedules of time-restricted feeding
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can impact our health in different ways.
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And when I say different ways,
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I mean, we're going to talk about how intermittent fasting,
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AKA time-restricted feeding, impacts weight loss,
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fat loss in particular,
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muscle maintenance and loss and gain,
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organ health, such as gut health and liver health,
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the genome, the epigenome, inflammation, sickness,
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recovery and healing from sickness,
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exercise, cognition, mood, and lifespan.
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So we're going to cover a tremendous amount of information.
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I promise to make it all directly accessible,
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regardless of whether or not you have a background
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in biology and metabolic science or not.
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I'm also going to talk about a lot of tools.
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In fact, I'm going to discuss a number of tools
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during today's episode that actually make it such
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that you don't have to follow any feeding schedule
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or fasting schedule, same thing if you think about it,
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in any absolutely strict regimented way,
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meaning if you were to only eat
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during an eight-hour period of each day, most of the time,
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but then occasionally eat
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across a 12-hour period of the day.
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In theory, that could actually have
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pretty serious detrimental health effects.
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And yet there are things that you can do
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to attenuate those negative effects.
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In fact, there are things that you can do and or take
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that can make it as if you did not eat at all.
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And so we'll discuss what those tools are.
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And in many cases for sake of health, weight loss,
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and performance,
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making the body think that it did not eat at all
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can actually be quite beneficial.
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So today we're going to cover mechanism
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and we're going to cover tools.
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Before we do that,
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I want to highlight a particular result
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that was published recently
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because it serves as a useful backbone
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as we wade into the conversation about fasting.
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This is a study that was published
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in the journal Cell Metabolism,
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a cell press journal, excellent journal.
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And the title of the paper is Fasting Blood Glucose
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as a Predictor of Mortality, Lost in Translation.
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And I'll explain what the lost in translation part
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means in a moment.
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But the basic takeaway of this study,
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and I should mention that the first author of the study
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is Paliyaguru, P-A-L-L-I-Y-A-G-U-R-U, guru,
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Paliyaguru et al.
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The basic finding of the study is that in humans,
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higher blood glucose is associated with mortality.
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And in fact, if you look at blood glucose,
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resting blood glucose across the lifespan,
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what you find is as people age,
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resting blood glucose goes up.
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Now this is very interesting because for a long time,
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it was thought that metabolism actually goes down as we age.
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And to some extent that's true,
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but the reductions in metabolism are not nearly as robust
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as we once thought that they were across the lifespan.
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However, unless there's something done to mitigate
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the increase in blood glucose associated with aging,
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almost everybody experiences a gradual,
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but regular increase in resting blood glucose
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that predicts mortality.
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Now the title, as I mentioned,
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is Fasting Blood Glucose as a Predictor of Mortality,
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Lost in Translation.
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And the reason that they included lost in translation
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in the title is that what I just told you,
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that increases in resting blood glucose predict mortality
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or are correlated with mortality is true for human beings
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and for non-human primates, monkeys,
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but the opposite is true in mice.
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And so I thought it was important to use this study
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as an example of where studies in mice often,
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but not always translate to humans and to non-human primates.
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So today I'm going to be careful to distinguish
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when a study was performed in mice versus in humans,
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because it seems that at least when discussing feeding,
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blood glucose and other aspects of diet,
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as they relate to health and wellbeing,
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whether or not a study was performed in rodents
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or in humans can be very important.
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In this case,
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the results were directly 180 degrees opposite
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to one another.
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In other words, in mice, resting blood glucose went down
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and it was associated with mortality.
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So lower blood glucose associated with mortality,
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whereas in humans,
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higher resting blood glucose was associated with mortality.
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And obviously what we're mostly interested in
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is health and wellbeing of ourselves, of humans.
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I'm sure there are some people out there
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that are intensely concerned about the health
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and wellbeing of mice,
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which you could imagine a few rare contexts
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where that's important,
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but obviously most of us are interested in human health.
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So I'll be sure to emphasize when studies were performed
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in humans versus in mice.
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Before we begin,
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I'd like to emphasize that this podcast is separate
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from my teaching and research roles at Stanford.
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It is however,
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part of my desire and effort to bring zero cost
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to consumer information about science
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and science related tools to the general public.
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In keeping with that theme,
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I'd like to thank the sponsors of today's podcast.
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This is an event that was recorded.
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The event was held by Logitech,
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and I was fortunate enough to partake in this event.
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And the entire event was centered around
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how to be a more effective learner and teacher
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using the modern principles of neuroplasticity.
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So at the link in the caption for this episode,
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you can go to what was called the Rethink Education event.
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And there, I gave a seminar of about 20 or 30 minutes
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describing the modern neuroscience of neuroplasticity,
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the nervous system's ability to change
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in response to experience.
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I focused mainly on human studies
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and tools that one can implement in the classroom
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and outside of the classroom can lead to faster
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00:10:37.060
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music skills, mathematical skills, language skills, et cetera,
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all based on quality peer viewed research.
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So if you'd like to check that out,
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you can head to that link.
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You'll also see an example of some of those tools in action
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in a music classroom of a phenomenal music teacher,
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Ben Edy, who's a teacher out in Pasadena,
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00:11:01.120
who has applied these tools,
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at least to my knowledge for the first time ever.
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Of course, all the tools that are there are listed out
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in what I call a plasticity super protocol.
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And all those tools can be applied to learning and teaching
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in any format that you like.
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So check it out.
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00:11:16.660
It's in the caption to this week's episode
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and it will remain there.
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It's up on YouTube and I hope you enjoy it.
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00:11:23.140
Okay, so let's talk about feeding,
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fasting, health, and performance.
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And I want to just establish a few foundational terms
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so that we're all on the same page.
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First of all,
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rather than talk about fasting or time restricted feeding,
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I'm largely going to talk about time restricted feeding,
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but please understand that time restricted feeding
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is just one side of the coin that is a two-sided coin
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that includes fasting on the one hand, not eating,
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and time restricted feeding on the other hand.
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I may occasionally say fasting,
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but because fasting and eating establish
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different biological conditions in the body,
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time restricted feeding is the term that I will use
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to describe the overall plan
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of restricting one's eating window as it's called
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to a particular phase of each 24 hour day,
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or in some cases to particular days within the week,
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because as you'll soon learn,
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there are aspects of time restricted feeding,
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AKA fasting, that involve eating every other day
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or eating one way for five days
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and then fasting for two days and so forth.
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So I'll be very precise about what I mean
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and why I mean it, but for the time being,
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I'm going to refer to time restricted feeding
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as a way to put an umbrella over this conversation.
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Second of all,
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I am going to emphasize a lot of biological mechanism.
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If you've listened to this podcast before,
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you know that I always begin with biological mechanism.
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I do describe tools of how to implement those mechanisms,
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but I wholeheartedly believe that knowing mechanisms
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and understanding how these processes work
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gives you tremendous flexibility and understanding
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and control over the processes
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of your mental and physical health.
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Whereas if I were to just list off a menu of things to do
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and not to do, those will work,
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but those will not give you the kind of understanding
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that would allow you to navigate through life,
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through travel, through dinners out,
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through different exercise schedules,
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whether or not you're one age or another age,
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male, female, et cetera,
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I'm giving you mechanisms so that you can gain more control
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over the systems in your brain and body.
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Everything's timestamped,
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so if you want to jump to the to-dos,
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you can certainly do that,
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but I encourage you to hang in there for the mechanism bit.
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I will make it all very clear
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because if you understand mechanism,
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you are in a true place of power
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and control over your biology.
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If ever there was a topic that is controversial,
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especially on the internet,
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it is that of diet and nutrition.
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So I'm wading into this with a smile
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and in eager anticipation of all the,
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but, but, but this, and but, but that, and wait,
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but this showed that.
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Here's the deal.
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00:14:11.900
We need to precisely define what it is
link |
00:14:14.860
that we're talking about when we talk about nutrition.
link |
00:14:18.120
I'm going to give you an example of a study
link |
00:14:20.160
that was published a few years ago, 2018,
link |
00:14:22.780
by a colleague of mine at Stanford, Chris Gardner.
link |
00:14:26.540
So a terrific professor of nutrition
link |
00:14:29.900
and has done a lot of important studies
link |
00:14:32.300
on how nutrition impacts different aspects of health.
link |
00:14:36.320
This is a large scale study.
link |
00:14:37.980
It was published in JAMA,
link |
00:14:39.620
the Journal of the American Medical Association,
link |
00:14:41.620
one of the very top tier journals in the area of medicine.
link |
00:14:45.660
And certainly for a paper on nutrition to show up there
link |
00:14:48.540
meant that it had to meet an exceedingly high standard.
link |
00:14:52.700
This paper where Chris is the first author,
link |
00:14:56.220
it's Gardner et al, 2018 JAMA,
link |
00:14:59.580
looked at weight loss in people following
link |
00:15:03.780
one particular diet versus another particular diet.
link |
00:15:06.980
And this was a 12 month weight loss study.
link |
00:15:09.500
So it was focused specifically on weight loss,
link |
00:15:12.140
although they looked at some other parameters as well.
link |
00:15:14.580
And the basic conclusion of the study was that
link |
00:15:17.620
there was no significant difference in weight change
link |
00:15:20.300
between people following a healthy low fat diet
link |
00:15:23.540
versus a healthy low carbohydrate diet
link |
00:15:25.760
with significantly more dietary fats in them.
link |
00:15:29.280
This caused a lot of ripples in the world of nutrition
link |
00:15:33.700
and nutritional science,
link |
00:15:35.020
and certainly in the general population,
link |
00:15:37.380
because anyone that understands diet and nutrition
link |
00:15:41.020
would immediately say, but wait,
link |
00:15:42.940
there are all sorts of different implications
link |
00:15:45.020
of eating one type of diet,
link |
00:15:46.980
say low carbohydrate, higher fats,
link |
00:15:49.100
versus a higher carbohydrate, lower fat diet.
link |
00:15:52.100
And indeed there are.
link |
00:15:53.560
This study was focused specifically on fat loss
link |
00:15:57.220
and on weight loss.
link |
00:15:58.980
So as we discuss time restricted feeding,
link |
00:16:03.340
we need to be very precise about what are the effects
link |
00:16:06.060
of time restricted feeding and of eating in particular ways
link |
00:16:09.780
at particular times,
link |
00:16:11.560
we are going to emphasize again,
link |
00:16:13.140
whether or not the study was done in mice or in humans,
link |
00:16:15.900
in athletes and men and women or both.
link |
00:16:18.460
But the study from Gardner and colleagues
link |
00:16:20.740
is a beautiful study and really emphasizes that
link |
00:16:23.680
if one's main goal is simply to lose weight,
link |
00:16:27.640
then it really does not matter what one eats,
link |
00:16:31.940
provided that the number of calories burned
link |
00:16:35.360
is higher than the number of calories ingested.
link |
00:16:38.140
However, anyone out there who understands
link |
00:16:41.900
a little bit of biology or a lot of biology will agree
link |
00:16:45.980
that there are many factors that impact
link |
00:16:48.340
that calories burned part of the equation.
link |
00:16:50.960
Some of those are obvious.
link |
00:16:52.340
So for instance, amount of exercise,
link |
00:16:55.220
type of exercise, basal metabolic rate,
link |
00:16:57.860
how much energy one burns just sitting there.
link |
00:17:00.540
I've talked before on this podcast about meat,
link |
00:17:02.540
non-exercise induced thermogenesis,
link |
00:17:04.740
where if people bounce around a lot and fidget a lot,
link |
00:17:07.240
they can burn anywhere from 800 to 2000 calories per day.
link |
00:17:11.020
So their quote unquote basal metabolic rate
link |
00:17:13.500
is actually much higher simply because they're fidgeters.
link |
00:17:15.580
Whereas people who tend to be more stationary
link |
00:17:17.320
have a lower basal metabolic rate on average.
link |
00:17:19.780
There's a great science to support this.
link |
00:17:22.660
Metabolic factors and hormones are also very important.
link |
00:17:27.140
Hormones such as thyroid hormone and insulin
link |
00:17:30.360
and growth hormone and the sex story to hormones,
link |
00:17:32.560
testosterone and estrogen,
link |
00:17:34.260
those levels will also profoundly influence
link |
00:17:37.000
the calories out the calories of burned component
link |
00:17:39.680
of the calories in calories out equation.
link |
00:17:42.500
So if out there on the internet
link |
00:17:45.420
or in listening to a particular podcast or speaker,
link |
00:17:48.300
somebody says, this is the ideal diet
link |
00:17:50.820
or calories in calories out does not matter
link |
00:17:53.660
or calories in calories out is the only thing that matters.
link |
00:17:56.460
I think it's very important to understand
link |
00:17:58.100
that there are some foundational truths
link |
00:17:59.960
such as calories in calories out,
link |
00:18:01.940
but that of course hormone factors
link |
00:18:04.960
and the context in which a given diet regimen
link |
00:18:08.660
is taking place are exceedingly important.
link |
00:18:11.180
A good example of this would be puberty.
link |
00:18:14.120
At that time in life,
link |
00:18:16.120
sex story to hormones are changing profoundly in the body
link |
00:18:18.680
as our growth hormone and other hormones.
link |
00:18:21.220
And much of caloric intake
link |
00:18:23.300
is directed towards protein synthesis,
link |
00:18:26.220
towards the production of muscle and bone
link |
00:18:27.860
and other tissues of the body.
link |
00:18:29.220
And that's because of changes in hormones
link |
00:18:31.100
that we call puberty.
link |
00:18:32.460
So there's no way that we can drill into every aspect
link |
00:18:36.560
of a given feeding plan or feeding schedule
link |
00:18:41.480
that would allow us to tap into every aspect
link |
00:18:43.860
of the list that I read out before weight loss,
link |
00:18:46.700
fat loss, muscle, organ, genome, epigenome,
link |
00:18:48.660
inflammation, exercise, cognition, mood, and lifespan.
link |
00:18:51.500
But today we're going to be very precise
link |
00:18:53.060
about how time restricted feeding.
link |
00:18:55.980
It's very clear from both animal studies
link |
00:18:58.460
and human studies can have a very powerful
link |
00:19:02.040
and positive impact on everything from weight loss
link |
00:19:06.060
and fat loss to various health parameters.
link |
00:19:09.540
This is a beautiful literature that's emerged mostly
link |
00:19:12.820
in the last 10 or 15 years.
link |
00:19:15.020
And as we march into this literature,
link |
00:19:16.680
what you'll see is that there actually is a perfect diet
link |
00:19:20.140
for you on a given day.
link |
00:19:23.260
And that perfect diet for you on a given day is contextual,
link |
00:19:27.820
meaning it depends on what you did yesterday
link |
00:19:30.660
and what you're going to do tomorrow.
link |
00:19:32.920
So there is a perfect diet for you.
link |
00:19:34.960
And today I'm going to arm you with the mechanisms
link |
00:19:37.080
and understanding that will allow you to define
link |
00:19:39.440
what that perfect diet is,
link |
00:19:40.980
and will allow you to eat on a schedule
link |
00:19:43.980
and to eat the things that are going
link |
00:19:46.220
to best serve your goals.
link |
00:19:48.200
So let's talk about eating and what happens when you eat.
link |
00:19:51.360
And let's talk about fasting or not eating
link |
00:19:54.340
and what happens when you fast.
link |
00:19:56.740
I did an entire episode on eating and metabolism
link |
00:19:59.980
and hormones and other factors that impact appetite.
link |
00:20:03.640
We don't have time to go into all those details now,
link |
00:20:05.660
although you're welcome to listen to that episode as well.
link |
00:20:10.080
But we can briefly describe the overall conditions
link |
00:20:13.500
that are set in the body when we eat and when we don't eat.
link |
00:20:18.500
The key word here is conditions.
link |
00:20:21.100
If I can emphasize anything today,
link |
00:20:23.340
it's that what you eat and when you eat it,
link |
00:20:26.820
set conditions in your body.
link |
00:20:29.420
And those conditions can be very good for you
link |
00:20:31.720
or very bad for you, depending on when you eat.
link |
00:20:35.780
In fact, when you eat is as important as what you eat.
link |
00:20:41.740
I'll repeat that.
link |
00:20:42.580
When you eat is as important as what you eat,
link |
00:20:44.780
at least as it relates to health parameters,
link |
00:20:47.040
in particular, liver health and mental health.
link |
00:20:50.340
Some simple rules about eating.
link |
00:20:52.540
First of all, when you eat, typically your blood glucose,
link |
00:20:56.500
your blood sugar will go up.
link |
00:20:58.300
Also insulin levels will go up.
link |
00:21:01.280
Insulin is a hormone that's involved in mobilizing glucose
link |
00:21:04.540
from the bloodstream.
link |
00:21:06.300
How much your glucose and insulin go up
link |
00:21:09.620
depends on what you eat and how much you eat.
link |
00:21:12.820
In general, simple sugars, including fructose from fruit,
link |
00:21:17.860
but also sucrose and glucose and simple sugars
link |
00:21:20.980
will raise your insulin and blood glucose
link |
00:21:23.220
more than complex carbohydrates,
link |
00:21:26.260
things like grains and breads and pastas and so forth.
link |
00:21:28.940
And grains and breads and pastas and so forth
link |
00:21:31.200
will raise your blood glucose more
link |
00:21:32.940
than fibrous carbohydrates like lettuce and broccoli
link |
00:21:36.260
and things of that sort.
link |
00:21:38.180
Protein has a somewhat moderate or modest impact
link |
00:21:41.880
on insulin and glucose.
link |
00:21:43.180
And fat has the lowest impact
link |
00:21:45.540
on raising your blood glucose and blood insulin.
link |
00:21:48.780
So what you eat will impact how steep arise in blood glucose
link |
00:21:53.660
and insulin takes place.
link |
00:21:55.420
And there are a number of factors
link |
00:21:57.260
that are related to your individual health
link |
00:21:59.220
that will also dictate how steep and how high
link |
00:22:01.780
that rise in glucose and insulin will be.
link |
00:22:04.540
For the time being,
link |
00:22:05.540
I'm leaving out people who have type one diabetes.
link |
00:22:08.360
These are people that don't manufacture their own insulin
link |
00:22:10.900
and type two diabetes is essentially insulin insensitivity,
link |
00:22:16.880
lack of sensitivity to insulin,
link |
00:22:18.520
which leads to high blood glucose.
link |
00:22:20.840
But when you eat, blood glucose goes up
link |
00:22:23.800
and when you don't eat blood glucose and insulin go down.
link |
00:22:27.660
The longer it's been since your last meal,
link |
00:22:29.820
the lower typically your blood glucose and insulin will be.
link |
00:22:33.620
And the higher things like GLP-1,
link |
00:22:36.580
glucagon like peptide one,
link |
00:22:40.420
glucagon being a hormone that's also secreted
link |
00:22:44.660
when you are in a fasted state or a low blood glucose state.
link |
00:22:49.260
It's involved in mobilizing various energy sources
link |
00:22:53.160
from the body, including fat through what we call lipolysis,
link |
00:22:57.120
also using carbohydrates and potentially even using muscle
link |
00:22:59.960
as a source of energy.
link |
00:23:01.240
So that's kind of a fire hose of information
link |
00:23:06.460
about what happens when you eat and don't eat,
link |
00:23:08.100
but just think of it this way,
link |
00:23:09.640
blood sugar and insulin go up when you eat,
link |
00:23:11.980
they go down when you don't eat
link |
00:23:13.300
and other hormones go up when you don't eat.
link |
00:23:16.180
So there are hormones associated with the fasted state
link |
00:23:19.300
and there are hormones associated with the eating
link |
00:23:22.040
and having just eaten state.
link |
00:23:25.000
Now, the most important thing to understand
link |
00:23:28.540
is that like everything in biology,
link |
00:23:31.500
this is a process that takes time.
link |
00:23:34.300
So insulin and glucose go up when we eat
link |
00:23:37.580
and it takes some period of time for them to go down.
link |
00:23:39.980
Even if we stop eating,
link |
00:23:42.020
they will remain up for some period of time
link |
00:23:44.100
and then go back down.
link |
00:23:45.460
It takes time.
link |
00:23:47.340
This is very important because if you look
link |
00:23:49.740
at the scientific literature on fasting,
link |
00:23:52.740
on time restricted feeding,
link |
00:23:55.200
it's absolutely clear that the health benefits,
link |
00:23:58.940
not just the weight loss benefits,
link |
00:24:00.380
but that the health benefits from time restricted feeding
link |
00:24:03.620
occur because certain conditions are met
link |
00:24:06.340
in the brain and body for a certain amount of time.
link |
00:24:10.300
And that gives us an anchor from which to view
link |
00:24:14.340
what eating is in terms of how it sets conditions
link |
00:24:17.740
in the body over time.
link |
00:24:19.600
And if that sounds overly analytic,
link |
00:24:22.160
I promise you this is the simplest and best way
link |
00:24:24.740
to think about any eating schedule or any eating plan.
link |
00:24:28.500
So I think it's fair to say that in the field of nutrition,
link |
00:24:31.740
there are a few landmark studies that serve
link |
00:24:34.680
as really strong anchors for building our understanding
link |
00:24:38.260
of what to eat and what not to eat and when to eat,
link |
00:24:40.660
depending on our goals.
link |
00:24:42.300
The Garner study that I mentioned earlier
link |
00:24:44.340
is one such study in that it says,
link |
00:24:47.500
if your goal is weight loss,
link |
00:24:49.380
it really does not matter what foods you consume
link |
00:24:53.460
provided that you consume a sub maintenance caloric diet.
link |
00:24:57.880
However, I want to emphasize again,
link |
00:25:00.460
that sets aside issues of adherence,
link |
00:25:04.200
meaning how easy or hard it is to adhere to a given diet.
link |
00:25:07.640
Some people find it much easier to follow a high fat,
link |
00:25:10.180
low carbohydrate diet.
link |
00:25:11.220
Some people follow a different diet
link |
00:25:13.180
because it's much easier for them to follow.
link |
00:25:15.580
And some people are concerned with mental performance
link |
00:25:17.960
and athletic performance.
link |
00:25:18.960
So that study doesn't say there's a best diet.
link |
00:25:22.100
What it says is that what you consume is less important
link |
00:25:26.420
than the amount of food that you consume,
link |
00:25:28.600
at least for sake of weight loss,
link |
00:25:30.940
not necessarily for sake of health.
link |
00:25:33.620
Now, the study that I'm going to refer to next
link |
00:25:36.900
is what I would consider the second major pillar
link |
00:25:39.900
of nutritional studies.
link |
00:25:41.020
This is a truly landmark study that was carried out
link |
00:25:44.460
by Sachin Panda, who is a professor
link |
00:25:47.680
at the Salk Institute of Biological Studies in San Diego,
link |
00:25:50.500
an absolutely phenomenal institution
link |
00:25:52.860
and an absolutely phenomenal researcher.
link |
00:25:55.260
I've known Sachin for a number of years.
link |
00:25:56.940
And I want to emphasize that the current literature
link |
00:26:00.580
on intermittent fasting and time restricted feeding
link |
00:26:03.700
can largely be attributed to Sachin
link |
00:26:07.040
and the work that he's done.
link |
00:26:08.180
There are others involved too, of course.
link |
00:26:10.940
And of course, time restricted feeding and fasting
link |
00:26:13.260
has a rich history that goes back many hundreds,
link |
00:26:16.340
if not thousands of years in different cultures
link |
00:26:18.340
and religions, but the science of time restricted feeding
link |
00:26:21.500
can really mainly be attributed to the incredible work
link |
00:26:24.280
that Sachin has done.
link |
00:26:25.620
And I'm grateful to consider him a friend and a colleague.
link |
00:26:29.540
And we consulted at length in anticipation of this episode.
link |
00:26:32.500
I also hope to have him on as a guest in the future.
link |
00:26:35.140
The landmark paper that came from Sachin's lab
link |
00:26:37.780
was published in 2012.
link |
00:26:39.780
This was a paper in mice that set the basis
link |
00:26:42.860
for studies in humans that came later.
link |
00:26:44.940
And the title of this paper is time restricted feeding
link |
00:26:47.960
without reducing caloric intake prevents metabolic diseases
link |
00:26:52.020
in mice fed a high fat diet.
link |
00:26:54.660
So the title tells us a lot.
link |
00:26:56.480
It says that what's varied in this study
link |
00:26:59.300
is not what these mice ate.
link |
00:27:01.860
It was when they ate it.
link |
00:27:03.940
And there were essentially four conditions in this study
link |
00:27:06.760
and the results are absolutely remarkable.
link |
00:27:09.580
So I'm going to walk you through the major results.
link |
00:27:12.400
What they did is they gave mice access
link |
00:27:15.540
to different types of food.
link |
00:27:17.460
There were four groups.
link |
00:27:18.840
One group of mice had access to just a normal mouse diet.
link |
00:27:23.420
It would not be a diet that you'd be very interested in.
link |
00:27:25.820
I confess I've actually tasted mouse chow.
link |
00:27:27.720
If you work with mice at all,
link |
00:27:28.820
you just have to do it at least once.
link |
00:27:30.480
It doesn't taste very good.
link |
00:27:31.420
It tastes like a very bland graham cracker cookie.
link |
00:27:33.620
And I confess that I only had the tiniest little bit,
link |
00:27:35.700
but mice like that stuff.
link |
00:27:37.420
And if you allow them to eat that stuff,
link |
00:27:39.340
what's called ad libitum, whenever they want,
link |
00:27:41.540
you just keep it in their food 24 hours a day,
link |
00:27:43.980
they will eat sometimes,
link |
00:27:45.200
and then they won't eat it at other times.
link |
00:27:46.940
Or in this case, they also had a condition
link |
00:27:49.780
where they gave them mouse chow in a time restricted way,
link |
00:27:52.820
just for a certain number of hours each day,
link |
00:27:56.180
about eight hours.
link |
00:27:59.360
Or they gave them a high fat diet that was a separate group,
link |
00:28:02.280
got a high fat diet at any time they wanted.
link |
00:28:04.820
So this was kind of the carnival for mice
link |
00:28:06.700
because mice really like high fat, highly palatable foods.
link |
00:28:09.640
And so they got a lot of goodies and high fat in their food.
link |
00:28:13.240
And then there was a fourth group that had access
link |
00:28:15.300
to the high fat diet as much as they wanted to eat,
link |
00:28:17.920
but only during a restricted time period
link |
00:28:20.900
of each 24 hour cycle.
link |
00:28:22.380
Now mice are nocturnal, humans are what we call diurnal.
link |
00:28:25.940
Actually, we're not really diurnal, we're crepuscular,
link |
00:28:28.340
which means that we're most active in the morning
link |
00:28:30.460
and in the evening, not so much in the afternoon.
link |
00:28:32.820
But nonetheless, everything I'm going to tell you
link |
00:28:37.140
is true also for humans.
link |
00:28:39.180
And we know this now from human studies.
link |
00:28:41.100
One of the most important things to take away
link |
00:28:42.820
from the study was that mice that ate a highly palatable,
link |
00:28:46.380
high fat diet, a great tasting diet,
link |
00:28:48.600
but only during a restricted feeding window
link |
00:28:50.740
of each 24 hour cycle,
link |
00:28:52.860
maintained or lost weight over time.
link |
00:28:55.900
Whereas mice that ingested the same diet,
link |
00:28:59.060
same amount of calories,
link |
00:29:01.820
but had access to those calories around the clock,
link |
00:29:05.260
gained weight, became obese and quite sick.
link |
00:29:08.620
And as an additional second point,
link |
00:29:10.860
the mice that restricted their feeding window
link |
00:29:13.680
to a particular portion of eight hours
link |
00:29:16.400
of every 24 hour cycle actually showed some improvement
link |
00:29:21.320
in important health markers.
link |
00:29:23.380
And what was even more incredible is that mice
link |
00:29:26.860
that only ate during a particular feeding window
link |
00:29:30.300
also experienced some reversal
link |
00:29:32.940
of some prior negative health effects.
link |
00:29:35.560
So this study really lit up the world
link |
00:29:38.300
and got people excited about time restricted eating.
link |
00:29:42.540
Again, they used an eight hour feeding window.
link |
00:29:46.460
The story around that eight hour feeding window
link |
00:29:48.340
is kind of interesting though.
link |
00:29:49.900
Not many people know this
link |
00:29:50.900
because it wasn't included in the paper
link |
00:29:52.900
and there was no reason to include it in the paper,
link |
00:29:56.700
not to out anybody,
link |
00:29:57.980
but it turns out that the reason
link |
00:29:59.700
they used an eight hour feeding window
link |
00:30:01.600
and not a nine hour or a 10 hour feeding window
link |
00:30:04.460
is because studies of this sort are actually quite demanding
link |
00:30:08.940
to perform and require the constant presence
link |
00:30:12.080
of the graduate student or postdoc there
link |
00:30:14.700
to ensure that the food is in the cages at particular times
link |
00:30:18.140
and not in the cages at other times.
link |
00:30:20.260
And mice are really good at hiding food.
link |
00:30:22.100
They'll even hide food in their jowls.
link |
00:30:25.380
And so there's a lot of work that has to be done
link |
00:30:27.420
to prepare for that eight hour feeding window
link |
00:30:29.620
and to make sure after that eight hour feeding window,
link |
00:30:32.680
there's all the food has been removed from the cage
link |
00:30:35.020
and from the jowls of the mice and so forth.
link |
00:30:37.060
And it turns out that the significant other
link |
00:30:39.780
of the graduate student and or postdoc,
link |
00:30:42.420
I won't reveal who they were running this study,
link |
00:30:45.220
forbid their significant other, the scientist,
link |
00:30:48.940
from being in the lab for periods of time
link |
00:30:52.060
that were much longer than the 10 or 12 hours
link |
00:30:54.220
that were required in order to ensure
link |
00:30:56.500
this eight hour feeding window.
link |
00:30:58.140
So when we hear the eight hour feeding windows are holy,
link |
00:31:01.120
they are not holy.
link |
00:31:02.140
And later we are going to talk about how eating for a time
link |
00:31:06.540
that's restricted to eight hours versus 10 hours
link |
00:31:08.620
versus 12 hours, for instance,
link |
00:31:10.860
how that impacts various parameters like health parameters
link |
00:31:14.300
and weight loss, et cetera.
link |
00:31:15.300
But the eight hour feeding window was actually created
link |
00:31:17.740
because of a real world constraint on the research
link |
00:31:20.100
and the relationship with the researcher
link |
00:31:21.820
performing the research,
link |
00:31:22.940
not because there's anything holy
link |
00:31:24.560
about an eight hour feeding window.
link |
00:31:26.460
Now, an important point about when the feeding window falls
link |
00:31:29.940
within the 24 hour cycle,
link |
00:31:31.900
it is very important that the feeding window fall
link |
00:31:34.900
during the more active phase of one's day.
link |
00:31:38.920
So for humans, that's typically in the early part of the day
link |
00:31:42.860
or the later part of the day, but not at night.
link |
00:31:45.540
Put very simply, there are a lot of data now
link |
00:31:48.500
pointing to the fact that eating during the nocturnal phase
link |
00:31:53.040
of the 24 hour cycle is very detrimental to one's health.
link |
00:31:57.980
In fact, when we eat can either enhance our health
link |
00:32:02.360
or can diminish our health.
link |
00:32:04.840
When we see light can enhance our feelings of wellbeing
link |
00:32:08.840
or can diminish our feelings of wellbeing.
link |
00:32:10.540
I've talked many times before about this
link |
00:32:12.160
on the Huberman Lab podcast that during the daytime,
link |
00:32:14.380
you want to get as much sunlight
link |
00:32:16.320
and other types of bright light in your eyes
link |
00:32:17.980
as is safely possible.
link |
00:32:19.300
And then you want to avoid light
link |
00:32:21.100
in the middle of the night.
link |
00:32:22.340
It has detrimental dopamine lowering effects,
link |
00:32:24.940
can cause depression, cortisol increases, et cetera.
link |
00:32:27.860
So when you view light is as important
link |
00:32:30.240
as the light that you view and when you eat
link |
00:32:33.140
is as important as what you eat.
link |
00:32:37.020
In this study, they saw something really interesting,
link |
00:32:40.500
which was that not only did restricting food
link |
00:32:43.820
to a particular phase of the 24 hour cycle
link |
00:32:46.460
benefit things like lean body mass and fat loss
link |
00:32:51.000
and a number of health parameters
link |
00:32:52.340
that I'll talk about in a moment,
link |
00:32:53.860
but it also anchored all the gene systems of the body
link |
00:32:57.900
and provided a more regular stable
link |
00:33:00.300
so-called circadian rhythm or 24 hour rhythm.
link |
00:33:03.060
You may be surprised to learn that 80%,
link |
00:33:06.100
80% of the genes in your body and brain
link |
00:33:11.180
are on a 24 hour schedule.
link |
00:33:13.820
That is they change their levels going from high to low
link |
00:33:16.980
and back to high again across the 24 hour cycle.
link |
00:33:19.900
And when those genes are high at the appropriate times
link |
00:33:22.740
and low at the appropriate times,
link |
00:33:24.220
meaning their expression is high and low
link |
00:33:26.560
at the appropriate times,
link |
00:33:28.060
and therefore the proper RNAs and proteins are made
link |
00:33:31.300
because DNA encodes for RNA,
link |
00:33:32.740
RNA is translated into proteins.
link |
00:33:36.620
When that happens, your health benefits.
link |
00:33:39.840
When those genes are not expressed at the right times,
link |
00:33:42.940
when they're high or low at the wrong times
link |
00:33:45.380
of each 24 hour cycle,
link |
00:33:46.700
that's when you get negative health effects.
link |
00:33:49.860
This study showed that when mice restrict their eating
link |
00:33:52.260
to an eight hour period within the most active phase
link |
00:33:56.140
of their 24 hour cycle,
link |
00:33:58.620
many of the genes that are associated
link |
00:34:00.420
with these so-called circadian and clocks,
link |
00:34:02.420
these genes have names like per, bmal, cry1, et cetera.
link |
00:34:06.640
Those so-called clock genes underwent
link |
00:34:09.560
a very regular entrainment,
link |
00:34:11.820
a locking in to the proper 24 hour schedule.
link |
00:34:15.220
And while this was in mice,
link |
00:34:16.540
we now know that this also occurs in humans.
link |
00:34:19.740
I've said before on this podcast, and I'll say it again,
link |
00:34:22.220
that light and when we view light is the primary way
link |
00:34:25.180
in which these genes and the clock systems of our body
link |
00:34:28.020
get organized or entrained,
link |
00:34:29.860
meaning matched to the outside light dark cycle.
link |
00:34:32.300
So viewing light early in the day and in the afternoon
link |
00:34:34.740
and as much as possible all day, great.
link |
00:34:36.900
Ideally that sunlight avoiding light in the middle
link |
00:34:39.260
of the night is also great.
link |
00:34:42.100
It's great because it causes the increases
link |
00:34:45.620
in particular genes and the decreases in particular genes
link |
00:34:47.900
in every cell throughout your body
link |
00:34:49.240
at the appropriate times.
link |
00:34:51.040
The second most powerful timekeeper or zeitgeber
link |
00:34:54.300
as it's called is food and when you eat.
link |
00:34:58.660
And in this study, the results they saw underscore
link |
00:35:02.620
this point, what they saw is that the peaks
link |
00:35:04.680
in these clock genes became very regular
link |
00:35:07.780
and the dips in these clock genes became very regular.
link |
00:35:10.580
And that led to a whole host
link |
00:35:13.460
of really important positive health effects.
link |
00:35:16.800
Conversely, when mice ate whenever they wanted
link |
00:35:19.660
across the 24 hour cycle,
link |
00:35:21.500
these clock genes became really out of whack
link |
00:35:24.160
and the negative health consequences
link |
00:35:26.860
were the downstream result of these changes
link |
00:35:30.220
in these clock genes.
link |
00:35:32.380
This has now also been shown to be true for humans.
link |
00:35:35.100
So if you want to be healthy, you want your organ health,
link |
00:35:38.100
your metabolic health to be entrained properly.
link |
00:35:42.400
One of the most important things you can do is to view light
link |
00:35:44.420
at the appropriate times of each 24 hour schedule
link |
00:35:46.440
and to not view light at other times of that schedule.
link |
00:35:49.060
And to eat at the appropriate time of each 24 hour day.
link |
00:35:53.720
Now, again, there are rare instances
link |
00:35:55.420
that we will discuss when skipping entire days
link |
00:35:58.180
or entire 24 hour cycles of eating can be beneficial.
link |
00:36:01.940
But for now, we're talking about schedules
link |
00:36:04.340
of time restricted feeding that involve a window
link |
00:36:07.220
of feeding that falls during your more active phase.
link |
00:36:09.540
So during the daytime, putting aside people
link |
00:36:12.500
that work shift work during the daytime
link |
00:36:14.360
is when you want to eat.
link |
00:36:15.920
And this eight hour feeding window provided a very strong
link |
00:36:20.100
reinforcing signal that combines with light
link |
00:36:23.620
to ensure that these genes are expressed
link |
00:36:25.300
at the appropriate times.
link |
00:36:27.120
The short takeaway from this is you probably want
link |
00:36:29.700
to think about and perhaps even engage
link |
00:36:32.340
in time restricted feeding.
link |
00:36:34.240
So as I mentioned earlier,
link |
00:36:35.320
when mice can eat around the clock, bad things happen.
link |
00:36:38.360
And one of the bad things that happens
link |
00:36:39.900
is that the liver suffers.
link |
00:36:42.580
The liver is involved in all sorts of things,
link |
00:36:45.260
production of important hormones
link |
00:36:46.620
and other factors related to metabolism.
link |
00:36:49.660
And when mice can eat around the clock,
link |
00:36:51.820
their livers got very sick, fatty deposits in the liver,
link |
00:36:55.520
other factors in the liver,
link |
00:36:56.920
essentially taking down the pathway of liver disease.
link |
00:37:00.020
The time restricted feeding essentially reversed that
link |
00:37:03.480
or led in many cases to even healthier liver conditions.
link |
00:37:06.760
And that's based on this study,
link |
00:37:07.800
but also additional studies also now in humans.
link |
00:37:11.640
So restricting your feeding to a particular window
link |
00:37:14.180
every 24 hour cycle has clearly been shown now
link |
00:37:16.980
in mice and in humans to enhance liver health,
link |
00:37:20.860
which is wonderful.
link |
00:37:23.020
How does it do this?
link |
00:37:24.220
Well, it happens because food intake,
link |
00:37:27.540
as I mentioned earlier,
link |
00:37:28.480
sets certain conditions in the body
link |
00:37:30.540
that lasts for a period of time.
link |
00:37:32.760
Anytime we eat, whether or not we are a mouse or a human,
link |
00:37:36.140
there's a period of time that's required
link |
00:37:38.080
for so-called digestion,
link |
00:37:39.820
but also gastric emptying and other processes related
link |
00:37:43.240
to breaking down that food and utilizing it.
link |
00:37:45.660
And that is an active process.
link |
00:37:47.340
It requires energy.
link |
00:37:49.280
And that process of breaking down food
link |
00:37:53.780
involves certain cellular functions
link |
00:37:55.980
that if they're ongoing throughout the 24 hour cycle
link |
00:37:59.620
or even extended too far across the 24 hour cycle,
link |
00:38:04.080
meaning you're eating across a 14 or a 16 hour
link |
00:38:06.740
and 18 hour window that causes serious problems.
link |
00:38:10.140
And this has now been established because of the fact
link |
00:38:13.880
that it increases the expression of different proteins
link |
00:38:17.580
and genes in the body, such as TNF alpha, IL-6, IL-1.
link |
00:38:21.020
What are all those things?
link |
00:38:22.260
They are pro-inflammatory markers.
link |
00:38:24.500
So the reason that the liver gets sick
link |
00:38:26.420
when you're eating too often
link |
00:38:28.180
is because inflammatory markers are increased.
link |
00:38:31.440
These inflammatory markers are not inherently bad.
link |
00:38:34.140
They're there for a reason,
link |
00:38:35.620
but they are there in order to respond
link |
00:38:38.060
to certain challenges, immune challenges,
link |
00:38:40.580
or the ingestion of food and the breakdown of food.
link |
00:38:42.900
But then in an ideal circumstance,
link |
00:38:45.900
they are reduced in the period
link |
00:38:48.520
in which there's no food present in the digestive tract
link |
00:38:51.340
or in which there's very little food present
link |
00:38:53.020
in the digestive tract.
link |
00:38:54.380
So by eating around the clock,
link |
00:38:55.860
you're making yourself sicker.
link |
00:38:57.300
By eating at restricted periods of time each 24 hour day,
link |
00:39:01.060
you're actually making yourself healthier
link |
00:39:02.900
and you're activating certain processes
link |
00:39:06.140
that can positively impact both weight,
link |
00:39:09.860
either maintenance or loss of weight.
link |
00:39:11.700
We'll talk about weight gain a little later
link |
00:39:13.340
and positively impacting things like liver health.
link |
00:39:16.020
Also the expression of different things
link |
00:39:18.420
related to brown fat,
link |
00:39:20.020
the fat that increases your metabolism.
link |
00:39:21.780
We will return to this also a little bit later
link |
00:39:24.180
and blood glucose regulation.
link |
00:39:27.260
So the takeaway from this study,
link |
00:39:29.460
in fact, there are many takeaways from this study.
link |
00:39:31.100
It's so wonderful is that liver health,
link |
00:39:35.380
bile acid metabolism, energy expenditure,
link |
00:39:38.220
inflammation, liver metabolites,
link |
00:39:42.540
many, many aspects of our health
link |
00:39:44.900
are impacted by when we eat, not just what we eat.
link |
00:39:48.300
As we move forward and we talk about intermittent fasting
link |
00:39:51.260
for eight hour windows, six hour windows,
link |
00:39:53.460
12 hour windows for all sorts of different
link |
00:39:56.100
intents and purposes,
link |
00:39:57.660
I want to start to establish a foundational protocol
link |
00:40:01.380
that all of us, any of us can use
link |
00:40:04.480
in order to maximize your particular goals.
link |
00:40:07.840
There are some absolutes within this realm
link |
00:40:10.700
of time restricted feeding.
link |
00:40:12.740
Here are a couple of absolutes
link |
00:40:14.360
that you would want to consider.
link |
00:40:15.740
First of all, it pays off in the metabolic sense
link |
00:40:21.220
and in the health sense
link |
00:40:22.620
and in the weight maintenance or loss sense
link |
00:40:25.960
to not ingest any food in the first hour after waking
link |
00:40:31.380
and potentially for longer.
link |
00:40:32.980
So I want to repeat that.
link |
00:40:33.900
One of the key pillars of intermittent fasting
link |
00:40:36.420
is that for the first hour after you wake up
link |
00:40:39.540
and potentially for longer to not ingest any food, okay?
link |
00:40:43.980
The second major pillar that's well supported by research
link |
00:40:47.740
is that for the two and ideally three hours
link |
00:40:51.380
prior to bedtime,
link |
00:40:52.940
you also don't ingest any food
link |
00:40:55.860
or liquid calories for that matter.
link |
00:40:57.580
And we will talk about what it means to break a fast
link |
00:41:00.740
and whether or not certain liquids,
link |
00:41:02.380
even coffee and tea can break a fast, et cetera,
link |
00:41:04.740
in a few moments.
link |
00:41:05.580
But just as a foundation,
link |
00:41:08.560
it's very clear from the research in humans
link |
00:41:10.980
that not eating any food or ingesting any calories,
link |
00:41:14.260
liquid or otherwise,
link |
00:41:15.580
for the first 60 minutes after waking up each day
link |
00:41:19.500
and for the two to three hours prior to your bedtime,
link |
00:41:23.860
that's ideal for the parameters
link |
00:41:26.540
that we've discussed earlier,
link |
00:41:27.780
all the different things like weight and liver health
link |
00:41:30.120
and metabolic health and so forth.
link |
00:41:32.320
The two most common questions about intermittent fasting
link |
00:41:34.900
are when is the ideal time for the eating window?
link |
00:41:38.060
Is it early in the day, the middle of the day,
link |
00:41:39.560
or late or in the day?
link |
00:41:41.140
And how long should that eating window be?
link |
00:41:43.900
Should it be eight hours?
link |
00:41:45.180
We already heard why the eight hour window
link |
00:41:47.320
was first established.
link |
00:41:48.700
It was because of these lab conditions
link |
00:41:50.280
and the conditions of the particular relationship
link |
00:41:52.320
of the graduate student involved,
link |
00:41:54.020
or should it be seven hours or six hours or 12 hours?
link |
00:41:57.180
Turns out that there's some general frameworks
link |
00:41:59.900
that we can follow in order to answer these questions.
link |
00:42:03.020
As we move into this portion of the discussion,
link |
00:42:05.080
I want to highlight a very important reference
link |
00:42:07.940
that just came out, literally came out last week
link |
00:42:11.340
in the journal, endocrinology reviews.
link |
00:42:14.020
And the title of this review is time restricted eating
link |
00:42:16.960
for the prevention and management of metabolic diseases.
link |
00:42:20.500
Although the data in this paper
link |
00:42:23.140
go well beyond metabolic diseases.
link |
00:42:25.060
This is a paper from Sachin Panda's lab.
link |
00:42:27.860
It's a very lengthy review with an enormous table
link |
00:42:31.540
that's beautifully organized,
link |
00:42:33.300
that scripts out all the studies done in humans,
link |
00:42:37.500
well over a hundred studies,
link |
00:42:39.540
looking at time restricted feeding in athletes,
link |
00:42:41.860
men, women, children, diabetes, no diabetes, et cetera,
link |
00:42:45.420
with detailed references and description of the outcomes.
link |
00:42:48.780
Spent a lot of time with this review,
link |
00:42:50.460
even though it just came out recently,
link |
00:42:52.100
and is a absolute goldmine resource.
link |
00:42:55.020
It is also the major resource
link |
00:42:56.500
for everything I'm about to tell you
link |
00:42:58.000
if you would like to delve deeper into the material.
link |
00:43:00.820
So let's deal with this first question
link |
00:43:02.940
of when is the ideal feeding window?
link |
00:43:05.500
And here again, we're thinking about a schedule of eating
link |
00:43:08.960
that involves eating at least once every 24 hours,
link |
00:43:12.100
not two day or three day or every other day fast.
link |
00:43:16.160
So it turns out that the answer to the question,
link |
00:43:18.600
when is it best to eat, is actually best answered
link |
00:43:22.140
by thinking about the other side of the coin,
link |
00:43:24.260
which is when is it best to fast?
link |
00:43:27.100
So because we are fasting during sleep,
link |
00:43:30.660
it's very clear that it's best to extend
link |
00:43:33.680
the sleep-related fast either into the morning
link |
00:43:38.220
or to start it in the evening.
link |
00:43:41.080
Now, this might seem kind of obvious,
link |
00:43:42.540
but it's actually not so obvious.
link |
00:43:45.260
You could place that feeding window early in the day,
link |
00:43:48.460
middle of the day, or late in the day.
link |
00:43:50.620
Let's think about what happens when we sleep.
link |
00:43:53.020
When we sleep, our body undergoes a number
link |
00:43:56.140
of different processes in the brain and body
link |
00:43:58.660
in order to recover the cells and tissues.
link |
00:44:01.700
Many of you have probably heard of autophagy,
link |
00:44:03.580
which is essentially a cleaning up, a gobbling up
link |
00:44:06.560
of dead cells and cells that are injured or sick.
link |
00:44:09.500
And this is a natural process that occurs,
link |
00:44:11.680
and it occurs mainly during sleep,
link |
00:44:13.460
although not only during sleep.
link |
00:44:17.100
Fasting of any kind does tend to enhance autophagy.
link |
00:44:21.380
It is not the only way to create autophagic conditions.
link |
00:44:26.420
Autophagic conditions can be created simply
link |
00:44:28.740
by following a sub caloric diet.
link |
00:44:30.660
And there are other things that one can do
link |
00:44:32.540
in order to trigger autophagy,
link |
00:44:34.820
but fasting does trigger autophagy.
link |
00:44:36.820
So when we're asleep,
link |
00:44:38.260
the bad cells are getting gobbled up and eaten,
link |
00:44:40.980
and the good cells also are undergoing
link |
00:44:43.880
certain repair mechanisms mainly related to,
link |
00:44:46.420
or at least governed by those circadian genes
link |
00:44:48.860
that we talked about earlier, those clock genes.
link |
00:44:51.460
So you're already fasting when you're asleep.
link |
00:44:54.620
And how deep you are into that fast depends
link |
00:44:57.960
on how long it was since your last meal.
link |
00:45:01.000
So if you fast early in the day
link |
00:45:04.220
and you've been asleep for five, six, seven, eight hours,
link |
00:45:08.380
I would hope somewhere between six and eight hours
link |
00:45:10.400
for most people is going to be beneficial.
link |
00:45:12.860
When you wake up, I mentioned earlier
link |
00:45:15.560
that you don't want to eat
link |
00:45:16.580
for at least the first 60 minutes after waking,
link |
00:45:19.200
but were you to extend that fasting to say 9 AM, 10 AM,
link |
00:45:24.200
11 AM, or even 12 noon or later,
link |
00:45:27.220
you are taking advantage of the deep fast
link |
00:45:29.740
that you were in during sleep
link |
00:45:31.940
and certainly toward the end of sleep.
link |
00:45:33.540
Now, why do I say deep fast?
link |
00:45:34.920
Well, because when we eat,
link |
00:45:38.860
the clearance of that food from our gut
link |
00:45:40.860
and the processes in our cells and organs
link |
00:45:44.420
that are related to digestion
link |
00:45:46.300
and the utilization of that food
link |
00:45:49.040
takes about five to six hours.
link |
00:45:51.460
So if you eat a meal and that meal lasts 10 minutes,
link |
00:45:55.680
20 minutes, or 30 minutes, or even an hour,
link |
00:45:57.900
and then you stop eating, you've stopped eating,
link |
00:46:00.500
but you are not fasting at that point.
link |
00:46:03.220
You can say you're fasting
link |
00:46:04.240
because you're no longer putting food
link |
00:46:05.640
into your digestive tract,
link |
00:46:07.500
but you are not in a fasted state.
link |
00:46:09.460
You are not under conditions of fasting.
link |
00:46:12.420
Later, I'll talk about things that you can do
link |
00:46:13.840
to accelerate the transition into fasting.
link |
00:46:16.380
So one thing is certain that you want your eating window
link |
00:46:20.120
to be tacked or attached to your sleep-based fasting
link |
00:46:25.580
in a way that makes it easier for you
link |
00:46:28.260
to get into the fasted state for a period of time.
link |
00:46:31.300
So we can view that point
link |
00:46:33.140
from the perspective of best, better, and worst, okay?
link |
00:46:39.300
So if you are like most people and you sleep at night,
link |
00:46:42.460
you're waking up somewhere around 6.37 AM
link |
00:46:44.700
or maybe even 8 AM,
link |
00:46:45.900
let's say you were to push your fasting window out
link |
00:46:49.180
such that you started eating at noon
link |
00:46:53.500
and then you stopped eating at 6 PM.
link |
00:46:57.700
Well, then you're not eating from 6 PM
link |
00:47:01.000
until let's say your bedtime is 10 PM,
link |
00:47:03.020
but from 6 PM to 10 PM,
link |
00:47:04.580
your body is not yet in a fasted state
link |
00:47:07.120
because you just ate.
link |
00:47:09.140
However, you're starting to taper into a fasted state
link |
00:47:12.440
before sleep and then all through sleep
link |
00:47:15.020
and until the next morning and late morning,
link |
00:47:17.740
you are actually in a fasted state.
link |
00:47:20.100
Now, most people find it very hard
link |
00:47:21.820
to only eat in the middle of the day.
link |
00:47:24.060
So while that's best,
link |
00:47:25.360
it's ideal for sake of the fasting-related improvements
link |
00:47:28.780
in health, it is not ideal
link |
00:47:31.020
and it's not very applicable
link |
00:47:33.860
to most work and family and social situations.
link |
00:47:37.260
Most people eat breakfast with others
link |
00:47:39.460
and or eat dinner with others.
link |
00:47:41.880
Some people eat lunch with others,
link |
00:47:43.500
but in general, it's hard to restrict your feeding window
link |
00:47:46.260
to just the absolute middle of the day.
link |
00:47:48.340
But from a purely health perspective,
link |
00:47:50.480
in a very objective way, that would be the ideal situation.
link |
00:47:54.060
Let's imagine a different pattern of eating
link |
00:47:56.260
where the feeding window starts in the afternoon,
link |
00:47:59.620
starts around two or even 3 PM.
link |
00:48:02.100
Some people don't have much trouble
link |
00:48:03.540
or they can train themselves to get their feeding window
link |
00:48:06.500
out to two or 3 PM
link |
00:48:08.620
and then they will eat until 10 or 11 PM, right?
link |
00:48:11.540
If you do the math,
link |
00:48:12.380
you realize that that feeding window is still pretty short.
link |
00:48:14.660
It still constitutes what we would call intermittent fasting
link |
00:48:17.540
or time restricted feeding.
link |
00:48:19.340
But assuming that they go to bed around 11 PM or midnight,
link |
00:48:24.460
they are not actually fasted in sleep
link |
00:48:26.960
because for the first six hours or so of sleep,
link |
00:48:30.380
maybe five, but probably more like six hours of sleep,
link |
00:48:32.860
they're still digesting the food
link |
00:48:34.180
that they consumed late in the night.
link |
00:48:36.700
It does appear beneficial to grab ahold of
link |
00:48:41.340
that sleep related fast,
link |
00:48:43.980
meaning you don't want your feeding window
link |
00:48:47.540
to be too close to bedtime.
link |
00:48:48.700
And that's why we came up with this
link |
00:48:50.140
kind of foundational pillar
link |
00:48:52.160
that I discussed with Sachin earlier,
link |
00:48:53.860
which is at least no eating for the first hour after waking,
link |
00:48:57.420
but also no eating within two to three hours prior to bed.
link |
00:49:01.680
And because we all need to sleep
link |
00:49:02.840
and sleep is exceedingly important
link |
00:49:04.840
for our health of all kinds,
link |
00:49:07.460
you want to prioritize sleep,
link |
00:49:08.740
but because we also have to eat,
link |
00:49:10.520
then you start to think about this
link |
00:49:11.780
and maybe it's not so good
link |
00:49:13.460
to push that feeding window too late in the day,
link |
00:49:16.260
because when you go to sleep,
link |
00:49:17.780
you're not actually capitalizing
link |
00:49:19.320
on the sleep related fasting.
link |
00:49:21.220
Now it's not just the case
link |
00:49:22.820
that it's easiest to fast while in sleep,
link |
00:49:24.720
although that's true because when we're asleep,
link |
00:49:26.540
typically we're not hungry or looking for food
link |
00:49:28.940
or foraging for food or wanting food
link |
00:49:30.560
or trying to resist food, we're just sleeping.
link |
00:49:33.980
There is something special about the fasting
link |
00:49:36.240
that occurs during sleep because it's associated
link |
00:49:39.260
with a number of processes
link |
00:49:40.820
that relate to the so-called glymphatic system,
link |
00:49:43.420
the movement of lymph-like fluids
link |
00:49:45.900
and other fluids through the brain
link |
00:49:47.340
are kind of sweeping out a garbage disposal, if you will,
link |
00:49:50.580
a clearing out of the metabolic debris
link |
00:49:53.020
and some of the autophagy that's associated
link |
00:49:55.260
with bad processes in the brain.
link |
00:49:58.660
So we could do a whole episode on this,
link |
00:50:00.300
but essentially during sleep
link |
00:50:01.740
and in particular during fasted states of sleep,
link |
00:50:05.260
we are undergoing a number of automatic cellular processes
link |
00:50:09.660
that clear out debris from our brain,
link |
00:50:11.900
enhance cognition, or at least offset dementia,
link |
00:50:14.680
this is now well-established,
link |
00:50:16.280
as well as a number of the same processes
link |
00:50:17.900
occurring in the organs of our body.
link |
00:50:19.860
So what we're starting to see here
link |
00:50:22.160
is that there are a number of constraints
link |
00:50:23.600
on when you can eat.
link |
00:50:24.940
Now I would be remiss if I didn't acknowledge
link |
00:50:27.580
the social constraints and the real life constraints.
link |
00:50:30.120
Some of us, because we want to eat with our family
link |
00:50:32.740
and because our family or our significant others
link |
00:50:35.700
eat around eight or 9 p.m.
link |
00:50:37.120
and that's the only time we're together,
link |
00:50:38.320
you have to eat late in the day.
link |
00:50:40.580
And that's certainly not a sin.
link |
00:50:41.900
I'm not saying that's good or bad.
link |
00:50:44.000
Here we're trying to establish, if you recall,
link |
00:50:45.900
best, better, and worst.
link |
00:50:48.020
So from both a practical and a health perspective
link |
00:50:52.020
and a purely objective view
link |
00:50:53.780
of how intermittent fasting works and can benefit us,
link |
00:50:58.200
starting to eat each day somewhere around 10 a.m.
link |
00:51:03.220
or around noon, and then allowing a feeding window
link |
00:51:07.240
that goes until six or maybe 8 p.m.,
link |
00:51:11.560
that seems to me, at least based on the data
link |
00:51:14.780
and what I understand about typical cultures
link |
00:51:17.080
where people eat in the daytime and in the evening,
link |
00:51:22.200
that seems to me like the kind of schedule
link |
00:51:24.180
that will allow you to get the most
link |
00:51:26.260
out of intermittent fasting, time-restricted feeding,
link |
00:51:29.900
but does not set you up to be really out of sync
link |
00:51:32.940
with the social rhythms in most cultures.
link |
00:51:36.380
If you think about it from the perspective of say,
link |
00:51:38.820
a noon to eight feeding window,
link |
00:51:42.220
what you'll find is that you're able to eat lunch
link |
00:51:44.460
with others, if you like, or by yourself,
link |
00:51:47.500
you will be able to eat dinner at a reasonable hour,
link |
00:51:50.420
at least in most countries, in most cultures,
link |
00:51:52.220
eating dinner somewhere between 6.30 and 7 p.m.
link |
00:51:56.180
is typical.
link |
00:51:59.100
When you say a feeding window that goes until eight,
link |
00:52:01.340
that doesn't mean sitting down to dinner at eight.
link |
00:52:03.940
That means your last bite of food or ingestion
link |
00:52:06.180
of any liquid calories was at 8 p.m.
link |
00:52:09.860
Assuming that you go to bed somewhere between 10 p.m.
link |
00:52:12.380
and 1 a.m., that allows this tapering off
link |
00:52:14.920
or this transition from feeding to a fasted state
link |
00:52:18.380
and still allows you to capitalize on the special period
link |
00:52:21.980
of fasting that is sleep-related fasting.
link |
00:52:24.900
And again, I want to emphasize that the fasting
link |
00:52:26.700
that occurs during sleep is vital
link |
00:52:28.460
and eating too close to sleep will disrupt
link |
00:52:31.200
that fasting-related sleep.
link |
00:52:33.620
Now, there are a number of caveats
link |
00:52:35.500
and details related to this,
link |
00:52:37.440
and there's an important caveat and detail related
link |
00:52:40.660
to people that are specifically interested
link |
00:52:43.160
in increasing or maintaining muscle mass.
link |
00:52:46.900
So first let's talk about food volume and food type
link |
00:52:51.660
and how that relates to whether or not you quickly
link |
00:52:55.660
or slowly enter a fasted state,
link |
00:52:58.180
because clearly when we talk about a feeding window,
link |
00:53:01.760
that feeding window could include any number
link |
00:53:03.440
of different foods.
link |
00:53:04.280
It could involve cake and ice cream, pizza, hamburgers,
link |
00:53:07.180
plants, fruit, whatever it is,
link |
00:53:09.720
or it could involve just fats or just proteins, et cetera.
link |
00:53:14.020
There are at least three factors that are going
link |
00:53:16.340
to govern how quickly you transition
link |
00:53:18.680
from ingesting food to a fasted state.
link |
00:53:22.040
Remember, as you ingest your last bite or sip of calories,
link |
00:53:26.940
that's not when the fast begins.
link |
00:53:28.460
That might be when the fasting begins on your watch
link |
00:53:31.260
or on one of these apps that I'll refer to later,
link |
00:53:33.220
which can help you track your fasting and eating windows,
link |
00:53:35.700
but that's not when it actually begins
link |
00:53:37.920
because your body is still seeing food.
link |
00:53:40.180
You're actually carrying around food inside of you.
link |
00:53:43.100
Even though you're not putting it into your mouth,
link |
00:53:45.180
you're still eating in some sense.
link |
00:53:47.940
So it should be somewhat obvious that very large meals
link |
00:53:51.260
are going to take longer to digest than very small meals.
link |
00:53:53.740
So that will impact how slowly or quickly you migrate
link |
00:53:58.060
from a fed state to a fasted state.
link |
00:54:01.820
There's no way I can spell out what exact volume of food
link |
00:54:05.220
you should ingest based on the size of your stomach
link |
00:54:07.260
and et cetera.
link |
00:54:08.540
But you're all familiar with being extremely full,
link |
00:54:11.520
very full, comfortably full, somewhat full,
link |
00:54:15.120
or not feeling full and feeling hungry.
link |
00:54:17.900
So learning to gauge food volume is important.
link |
00:54:21.660
Also foods that include some fats or a lot of fats
link |
00:54:25.820
will tend to slow gastric emptying time.
link |
00:54:28.780
And depending on the kind of fats,
link |
00:54:31.580
it could mean that a given meal is digested
link |
00:54:33.740
within three hours versus five hours.
link |
00:54:35.660
So more fats might be a large meal with a lot of fats
link |
00:54:38.420
has been going to take five or six hours.
link |
00:54:39.940
A smaller meal with less fat is going to be digested
link |
00:54:42.100
more quickly.
link |
00:54:43.420
Consuming calories in liquid form is going to mean
link |
00:54:45.880
that gastric emptying time is going to be faster.
link |
00:54:48.380
And then of course,
link |
00:54:49.260
there's the glucose and the insulin aspect to it,
link |
00:54:51.960
which is that foods that lead to big steep rises in glucose,
link |
00:54:55.540
like pure sugars, then your glucose will drop.
link |
00:54:59.020
However, if they're combined with fats,
link |
00:55:00.820
then it tends to be a more gradual rise in glucose
link |
00:55:02.880
and it's more sustained, et cetera.
link |
00:55:04.540
Fibrous foods will also create a more long lasting
link |
00:55:07.460
sustained release in glucose.
link |
00:55:11.460
The important thing here is to establish a feeding window
link |
00:55:14.540
that you can comfortably manage, okay?
link |
00:55:17.300
Meaning that on average,
link |
00:55:18.800
you can obey a six hour feeding window
link |
00:55:21.840
or an eight hour feeding window or a 10 hour feeding window.
link |
00:55:24.780
And then to place that feeding window in a social
link |
00:55:28.540
and life context that you can manage on a regular basis.
link |
00:55:32.440
Now there are two key points that have been gleaned
link |
00:55:35.020
from the scientific data about this feeding window
link |
00:55:37.900
and when to place it.
link |
00:55:39.340
And this is based on a really important experiment
link |
00:55:42.140
that Satchin and his colleagues have been doing.
link |
00:55:44.100
There's a website that they have,
link |
00:55:45.660
a zero cost website called My Circadian Clock.
link |
00:55:48.300
You can go to this website free of cost.
link |
00:55:50.820
There are a number of important resources there,
link |
00:55:52.660
but what they've done is they've examined
link |
00:55:55.280
the feeding behavior of thousands of people.
link |
00:55:58.780
People will take a picture of the food they're about to eat
link |
00:56:01.160
and it enters into their account,
link |
00:56:03.040
maybe your account if you create one on My Circadian Clock.
link |
00:56:05.920
And they do this over many days or weeks.
link |
00:56:08.700
What's great about this is it establishes
link |
00:56:11.820
what's essentially called a phytogram,
link |
00:56:14.100
a time in which people ate.
link |
00:56:16.500
And a number of important findings have emerged
link |
00:56:19.400
from these phytograms across large populations
link |
00:56:22.540
of people in different time zones
link |
00:56:24.060
with different schedules, et cetera.
link |
00:56:25.460
First of all, almost everybody underestimates
link |
00:56:29.900
their feeding window.
link |
00:56:31.040
Meaning people who think that they are
link |
00:56:33.340
on an eight hour feeding window or six hour feeding window,
link |
00:56:37.580
when their data are analyzed,
link |
00:56:41.000
it almost is always the case
link |
00:56:42.300
that they're actually on a feeding window
link |
00:56:43.780
that's one or even two hours longer than they think.
link |
00:56:46.860
You think, well, how could that possibly be?
link |
00:56:48.180
If people are taking their first bite at noon
link |
00:56:50.380
and they're taking their last bite at 8 p.m.,
link |
00:56:53.380
well, that must mean that they are on that feeding window
link |
00:56:57.020
of eight hours.
link |
00:56:58.380
And it turns out that people cheat,
link |
00:57:01.620
but they don't cheat in any kind of obvious way.
link |
00:57:03.460
They might have, you know, a glass of wine after dinner,
link |
00:57:06.420
or they'll have a cup of tea and a little bite of a cookie.
link |
00:57:08.660
And so when people are honest and they are honest
link |
00:57:10.780
in most cases for this experiment,
link |
00:57:14.280
what you find is that most people's eating window
link |
00:57:16.020
is actually quite a bit longer.
link |
00:57:17.160
So in discussing this with Sachin
link |
00:57:18.660
and reviewing the literature,
link |
00:57:20.560
it's clear that if you'd like to be
link |
00:57:22.380
on a 10 hour feeding window,
link |
00:57:25.960
that you should probably select an eight hour feeding window
link |
00:57:29.540
because there's always a little bit of a taper
link |
00:57:32.400
on either side of that eating window.
link |
00:57:34.180
Very few people are extremely strict
link |
00:57:36.640
about these eating windows.
link |
00:57:37.560
It's just hard to do in the context of life events
link |
00:57:39.800
and social gatherings and family and so forth.
link |
00:57:43.300
Okay, so as we build forward your ideal fasting
link |
00:57:47.020
slash time restricted feeding schedule,
link |
00:57:49.820
we now have several different rules that we can list out.
link |
00:57:52.980
First, at least no food for the first hour after waking up,
link |
00:57:57.060
at least one hour.
link |
00:57:59.260
Two, no food intake for two
link |
00:58:03.300
and ideally three hours prior to your bedtime.
link |
00:58:06.220
Three, if you want to select an eight hour feeding window,
link |
00:58:13.120
then you should probably focus
link |
00:58:14.660
on a six or seven hour feeding window
link |
00:58:16.280
because in reality your feeding window
link |
00:58:18.300
is going to be longer.
link |
00:58:19.980
Reality meaning real life constraints.
link |
00:58:23.020
And if you'd like to be on a 10 hour feeding window,
link |
00:58:25.740
you should probably select an eight
link |
00:58:27.180
or a nine hour feeding window
link |
00:58:28.740
because the way it plays out is that people
link |
00:58:30.420
almost always eat outside of their eating window somewhat.
link |
00:58:34.620
The other nice thing about selecting
link |
00:58:36.380
a slightly shorter eating window
link |
00:58:38.800
than is comfortable for you
link |
00:58:40.420
is that it takes into account
link |
00:58:41.820
that as you take your last bite
link |
00:58:44.900
or your last sip of calories,
link |
00:58:46.520
there's this time or taper
link |
00:58:49.300
before which you are actually in a fasted state.
link |
00:58:52.120
And because you're eating different things
link |
00:58:53.780
on different days presumably,
link |
00:58:55.500
some foods leave your gut more quickly,
link |
00:58:57.540
some things spike your insulin
link |
00:58:58.900
and your glucose more than others.
link |
00:59:01.140
Sometimes you eat more fat, sometimes less fat.
link |
00:59:04.620
This allows you to fall well within the margins
link |
00:59:07.980
of the benefits of time restricted feeding
link |
00:59:10.220
that have been demonstrated in humans,
link |
00:59:11.900
which generally involve an eight hour window or so.
link |
00:59:16.660
So I think this eight hour window
link |
00:59:18.600
or six hour window is a good thing
link |
00:59:20.700
to shoot for for most people.
link |
00:59:22.720
Some people, and we will discuss the exceptions,
link |
00:59:24.500
but some people truly are exceptions to this.
link |
00:59:26.980
They just require more food.
link |
00:59:29.400
And along those lines,
link |
00:59:30.660
I just now briefly want to touch on some of the studies
link |
00:59:32.740
that have looked at using a very short feeding window
link |
00:59:35.100
of about four hours.
link |
00:59:36.780
Nowadays, a number of people are doing
link |
00:59:38.400
the so-called one meal per day
link |
00:59:39.980
or are restricting their feeding window
link |
00:59:42.140
to just four hours or six hours.
link |
00:59:45.020
And that turns out to be an interesting strategy.
link |
00:59:48.320
And the data around it actually are a little bit surprising.
link |
00:59:51.340
One surprising thing to leap out
link |
00:59:52.980
of this massive literature review
link |
00:59:55.740
on time restricted feeding in humans
link |
00:59:58.060
is that relatively short feeding windows
link |
01:00:01.440
of say four to six hours
link |
01:00:03.140
do produce a number of positive health effects,
link |
01:00:06.100
things like increased insulin sensitivity,
link |
01:00:08.300
which we know is good.
link |
01:00:09.540
Remember type two diabetes is a reduction
link |
01:00:11.660
in insulin sensitivity,
link |
01:00:13.660
improvements in beta cell function and the pancreas,
link |
01:00:16.700
decreased blood pressure,
link |
01:00:18.100
decreased oxidative stress,
link |
01:00:20.900
decreases in things like evening appetite.
link |
01:00:24.100
So positive health effects
link |
01:00:25.540
and psychological effects in general.
link |
01:00:28.540
However, they either produce no change in body weight
link |
01:00:33.420
or they tend to produce even increases in body weight.
link |
01:00:37.700
Now, of course, there's variation between individuals
link |
01:00:40.240
and between studies,
link |
01:00:41.980
but this is somewhat surprising.
link |
01:00:43.660
So the eight hour feeding window
link |
01:00:45.200
seems to be very beneficial
link |
01:00:46.800
across almost all the parameters that we've discussed,
link |
01:00:49.940
inflammation, weight loss, fat loss, et cetera.
link |
01:00:53.420
And adherence, I should mention,
link |
01:00:54.900
people's ability to stick to the diet
link |
01:00:56.700
seems quite good on this eight hour feeding windows.
link |
01:01:00.000
But when people try and undergo
link |
01:01:01.820
very short feeding windows of four to six hours,
link |
01:01:04.860
it seems that they are overeating
link |
01:01:06.520
in that four to six hours,
link |
01:01:07.680
at least overeating with respect to their metabolic needs.
link |
01:01:13.020
Now, the contrast to this
link |
01:01:15.780
is the so-called one meal per day schedule.
link |
01:01:18.360
Very few studies on one meal per day.
link |
01:01:20.820
One meal per day, unless it's a very, very long meal,
link |
01:01:23.100
a sort of feast,
link |
01:01:24.160
typically would not last four to six hours,
link |
01:01:26.740
because it sort of depends on how you define a meal.
link |
01:01:28.820
But when you look at the very few,
link |
01:01:31.300
I should emphasize again,
link |
01:01:32.140
very few studies on one meal per day,
link |
01:01:34.220
people typically maintain or lose weight
link |
01:01:36.740
on the one meal per day schedule.
link |
01:01:38.540
So what we can say
link |
01:01:39.580
is that the seven to nine hour feeding window
link |
01:01:42.900
produces all of the major health benefits
link |
01:01:45.740
of time-restricted feeding,
link |
01:01:47.900
as well as being pretty straightforward
link |
01:01:49.780
for most people to adhere to on a regular basis.
link |
01:01:52.940
And on a regular basis turns out to be very important.
link |
01:01:55.140
I'll get back to that point in a moment.
link |
01:01:56.600
Whereas the four to six hour eating window
link |
01:01:58.900
doesn't seem to serve people
link |
01:02:00.380
as well as say a seven or eight hour eating window,
link |
01:02:03.020
simply because people are overeating
link |
01:02:04.720
during that eating window.
link |
01:02:05.860
And the one meal per day,
link |
01:02:07.640
while perhaps ideal for certain people's schedules,
link |
01:02:11.600
may actually cause people to under eat.
link |
01:02:13.360
And in some cases that might be what people want.
link |
01:02:15.360
They actually want to under eat.
link |
01:02:16.980
But when we start thinking about performance
link |
01:02:19.820
in work and in sport,
link |
01:02:22.740
and when we start considering hormone health
link |
01:02:25.460
and hormone production, fertility,
link |
01:02:27.860
that's when we can really start to look at
link |
01:02:30.140
the seven to nine hour feeding window
link |
01:02:33.420
versus the four to six hour feeding window
link |
01:02:35.260
versus the one meal per day type feeding window
link |
01:02:38.400
with some different objectivity.
link |
01:02:40.620
We can start to look at it through a different lens,
link |
01:02:42.400
because it turns out that when you place the feeding window
link |
01:02:46.540
and how long that feeding window is
link |
01:02:49.340
actually will impact a number of other things
link |
01:02:51.500
in particular hormones that can be very important
link |
01:02:54.460
for a number of things related to sex and reproduction
link |
01:02:58.040
can be related to performance at work,
link |
01:03:01.340
performance in athleticism.
link |
01:03:03.740
And there are excellent studies on this.
link |
01:03:05.660
So let's explore those now.
link |
01:03:07.920
So let's talk about some conditions
link |
01:03:09.500
where having the feeding window early in the day
link |
01:03:12.180
would actually be very beneficial.
link |
01:03:14.420
There was a study that was published recently
link |
01:03:16.420
in Cell Reports, again, Cell Press Journal,
link |
01:03:18.740
excellent journal, peer reviewed, very stringent
link |
01:03:22.460
from Aoyama et al.
link |
01:03:24.380
So this is A-O-Y-A-M-A et al.
link |
01:03:28.040
This was published just recently in July, 2021
link |
01:03:31.740
that looked at the distribution of protein intake
link |
01:03:37.040
in different meals delivered either early in the day
link |
01:03:40.860
or later in the day.
link |
01:03:42.080
And I'm summarizing here quite a lot,
link |
01:03:43.620
but I should mention that this study was performed
link |
01:03:46.420
in both mice and humans, same paper, mice and humans,
link |
01:03:50.200
and involved hypertrophy training,
link |
01:03:53.940
essentially increasing the weight bearing of given limbs
link |
01:03:57.940
to try and induce hypertrophy,
link |
01:03:59.840
which is the growth of muscle tissue.
link |
01:04:03.580
It does appear that muscle tissue is better able
link |
01:04:08.180
to undergo hypertrophy by virtue of the fact
link |
01:04:12.200
that there's better or enhanced protein synthesis
link |
01:04:15.740
early in the day because of the expression
link |
01:04:18.020
of one of these particular clock genes called BMAL, B-M-A-L.
link |
01:04:23.300
BMAL regulates a number of different protein synthesis
link |
01:04:26.400
pathways within muscle cells,
link |
01:04:28.840
such that eating protein early in the day
link |
01:04:32.300
supports muscle tissue maintenance and or growth.
link |
01:04:36.200
And in this study, they also looked at the effects
link |
01:04:38.480
of supplementing so-called BCAAs, branch chain amino acids,
link |
01:04:41.860
which is popular in bodybuilding circles
link |
01:04:44.860
and in strength training circles.
link |
01:04:46.380
And BCAAs are essential components
link |
01:04:48.900
of a number of different foods,
link |
01:04:51.740
but can also be supplemented.
link |
01:04:53.820
The takeaway of this study is pretty straightforward.
link |
01:04:56.100
However, the takeaway is if your main interest
link |
01:04:58.980
is maintaining and or building muscle,
link |
01:05:02.120
then it can be beneficial to ingest protein early in the day.
link |
01:05:05.620
You would still want to obey this,
link |
01:05:08.700
what we're calling a kind of foundational rule
link |
01:05:11.540
of not eating any food for the first hour post-waking,
link |
01:05:15.700
or at least the first hour post-waking.
link |
01:05:17.540
And the cutoff for when you would want to eat protein
link |
01:05:20.460
would be sometime before 10 AM.
link |
01:05:23.100
And there I'm averaging across
link |
01:05:24.580
a number of different situations.
link |
01:05:27.300
But in general, this BMAL expression is such that,
link |
01:05:30.800
let's say you wake up at 7 AM,
link |
01:05:32.460
your main interest is in hypertrophy
link |
01:05:35.500
or maintenance of muscle.
link |
01:05:36.740
Then you would want to ingest some protein
link |
01:05:38.580
sometime before 10 AM.
link |
01:05:39.980
But obviously if you're interested in getting
link |
01:05:42.420
the health effects of intermittent fasting,
link |
01:05:44.400
that you wouldn't ingest any food
link |
01:05:46.980
for at least the first 60 minutes upon waking.
link |
01:05:49.320
Now it's not as if at 1001 AM,
link |
01:05:52.900
a gate slammed shut and you can't generate hypertrophy.
link |
01:05:55.620
Of course, that's not the case.
link |
01:05:57.780
However, it's very interesting that it doesn't matter
link |
01:06:00.140
when the resistance training,
link |
01:06:01.640
the load bearing exercise occurs in the 24 hour cycle.
link |
01:06:06.020
So whether or not, in other words,
link |
01:06:07.660
people are training early in the day
link |
01:06:09.260
or they're training late in the day,
link |
01:06:12.280
it still appears that ingesting protein early in the day
link |
01:06:14.820
favors hypertrophy or that one is better,
link |
01:06:18.500
or I should say more easily able to access hypertrophy
link |
01:06:22.840
by way of these clock regulated protein synthesis mechanisms
link |
01:06:26.220
by ingesting protein early in the day.
link |
01:06:28.980
In no way, shape or form does this study say
link |
01:06:31.420
that ingesting protein later in the day
link |
01:06:33.200
is somehow bad for you.
link |
01:06:34.340
It just emphasizes the positive effects
link |
01:06:36.820
of ingesting protein early in the day
link |
01:06:39.960
for sake of muscle maintenance and or hypertrophy.
link |
01:06:42.940
So if you're somebody who's mainly concerned
link |
01:06:44.700
with muscle maintenance and hypertrophy,
link |
01:06:46.780
then it may make sense to move that feeding window
link |
01:06:50.540
earlier in the day.
link |
01:06:51.820
And certainly there are people out there
link |
01:06:53.520
who are interested in muscle maintenance and hypertrophy
link |
01:06:56.260
who aren't doing intermittent fasting at all.
link |
01:06:58.020
And that's also perfectly fine,
link |
01:06:59.220
but this just so happens to be an episode
link |
01:07:01.020
about intermittent fasting and time restricted feeding.
link |
01:07:04.540
There are of course modes of eating
link |
01:07:06.320
where one eats small meals spread throughout the day
link |
01:07:09.100
or weights meals differently,
link |
01:07:10.860
such that meals early in the day
link |
01:07:12.500
are larger than later in the day or vice versa.
link |
01:07:14.920
There are a near infinite number of ways to organize this.
link |
01:07:18.140
But if you are somebody who's interested in deriving
link |
01:07:21.100
the many clearly established health effects
link |
01:07:23.960
of time restricted feeding,
link |
01:07:25.160
and you are somebody who would like to maintain
link |
01:07:28.020
or build muscle,
link |
01:07:31.060
then ingesting proteins in the early part of the day
link |
01:07:35.040
would be important to you,
link |
01:07:36.580
at least on the basis of these results.
link |
01:07:38.840
And therefore that eight hour window
link |
01:07:41.400
that we've established as more or less ideal
link |
01:07:44.240
shifted to the later part of the day
link |
01:07:46.360
might not be as beneficial for you.
link |
01:07:48.660
Now, I can just personally say that for me,
link |
01:07:51.720
when I wake up in the morning,
link |
01:07:52.760
it's very easy for me to not eat until noon
link |
01:07:55.920
or one or 2 p.m.
link |
01:07:57.540
Eating early in the day is actually somewhat of a challenge.
link |
01:08:00.920
I discussed this point with Sachin
link |
01:08:02.720
because we were talking about
link |
01:08:04.220
how is it that one can move their feeding window
link |
01:08:07.220
or place themselves onto a different schedule
link |
01:08:09.920
of intermittent fasting.
link |
01:08:11.480
And it's very clear that one needs to provide
link |
01:08:14.000
a transition period in order for that to happen.
link |
01:08:16.720
You should allow yourself a transition period
link |
01:08:18.720
of anywhere from one week to 10 days
link |
01:08:21.820
in which you shift your feeding window
link |
01:08:23.720
by about an hour each day or so.
link |
01:08:26.800
And then once you establish a feeding window
link |
01:08:29.340
that feels comfortable for you
link |
01:08:30.880
and that you think you can maintain over time,
link |
01:08:33.180
that you simply maintain that feeding schedule
link |
01:08:35.680
for at least 30 days,
link |
01:08:37.920
but ideally you would do that indefinitely.
link |
01:08:40.280
Now, this turns out to be important
link |
01:08:41.840
based on data that they've gleaned
link |
01:08:43.600
from this my circadian clock,
link |
01:08:46.280
massive experiment that they've been doing
link |
01:08:47.760
where people are entering the times
link |
01:08:48.920
that they're feeding and eating.
link |
01:08:51.680
Excuse me, anytime we talk about mice,
link |
01:08:53.040
I always think about feeding
link |
01:08:54.080
because I come from a background
link |
01:08:55.800
and my lab works on both laboratory mice and on humans.
link |
01:08:58.440
Anytime I think about humans, I think about eating,
link |
01:09:00.240
but of course they are the same thing.
link |
01:09:03.640
The interesting thing to emerge
link |
01:09:05.000
from that very large data set in humans
link |
01:09:07.720
is that when people log their feeding times,
link |
01:09:10.780
as I mentioned before,
link |
01:09:11.700
oftentimes they think they're eating in an eight hour window
link |
01:09:15.000
but they are actually eating in a much broader window.
link |
01:09:18.280
However, even for people that are very good
link |
01:09:21.080
about restricting their feeding
link |
01:09:22.920
to a four or six or eight hour window,
link |
01:09:25.120
if they're very strict about the start and stop times
link |
01:09:27.360
when they ingest calories,
link |
01:09:28.760
one of the findings that's really been important to note
link |
01:09:32.560
is that almost every individual has a lot of drift
link |
01:09:36.960
in when that eating window resides in their 24 hour period.
link |
01:09:41.200
In particular on the weekends,
link |
01:09:43.260
people are either extending or shifting their feeding window
link |
01:09:48.160
in a way that makes it seem
link |
01:09:49.680
that they've traveled to another time zone
link |
01:09:51.740
and are eating according to another time zone.
link |
01:09:53.920
And this is extremely important.
link |
01:09:57.360
As I mentioned earlier,
link |
01:09:59.200
based on the 2012 study from Sachin's lab,
link |
01:10:02.880
we're eating at a particular phase of each 24 hour cycle
link |
01:10:07.480
can help enhance the expression of these clock genes.
link |
01:10:12.240
If you are eating within a very strict
link |
01:10:15.560
or semi-strict feeding window,
link |
01:10:17.180
but that feeding window is migrating around
link |
01:10:19.440
from day to day or five days a week,
link |
01:10:21.260
you're really organized about when that falls,
link |
01:10:23.940
let's say for sake of example,
link |
01:10:25.440
from noon to 8 PM, noon to 8 PM,
link |
01:10:27.880
Monday, noon to 8 PM, Tuesday, Wednesday,
link |
01:10:30.680
noon to 8 PM, Thursday, and so forth.
link |
01:10:32.480
But then on a Saturday, it's becoming 11 AM
link |
01:10:37.320
and you're ending it early,
link |
01:10:38.900
or perhaps you're starting early in the day on Sunday,
link |
01:10:43.320
you're having brunch that starts at nine 30 or 10,
link |
01:10:45.680
and then it's extending out still just eight hours,
link |
01:10:48.240
but it's shifting around.
link |
01:10:49.840
That can cause disruptions
link |
01:10:51.820
in these circadian clock mechanisms
link |
01:10:53.880
that cause disruptions in the downstream effects of eating
link |
01:10:58.680
that are taking at least two to three days to recover from.
link |
01:11:03.320
So obviously we don't want to be overly neurotic
link |
01:11:06.160
about this stuff,
link |
01:11:06.980
but because this is an episode about the science
link |
01:11:08.600
of intermittent fasting and time restricted feeding,
link |
01:11:11.760
as important as how long your feeding window is,
link |
01:11:16.520
is where that feeding window resides in each 24 hour cycle.
link |
01:11:21.040
And perhaps even more important than that
link |
01:11:23.220
is that it be fairly regular
link |
01:11:25.200
where that feeding window resides,
link |
01:11:27.080
because even if you have a very short feeding window,
link |
01:11:29.060
if it's drifting around from day to day,
link |
01:11:31.940
that actually offsets a number
link |
01:11:33.760
of the positive health effects of intermittent fasting.
link |
01:11:36.880
So to really just underscore the way
link |
01:11:38.360
that these different pieces
link |
01:11:39.920
of the biological puzzle fit together,
link |
01:11:42.920
if you are very strict or semi-strict
link |
01:11:45.280
about your eight hour feeding window,
link |
01:11:46.660
but on the weekends that eight hour feeding window
link |
01:11:48.600
is falling later than it normally would
link |
01:11:51.320
during the middle of the week,
link |
01:11:53.120
it is as if you are going to bed later,
link |
01:11:55.800
even if you're going to bed at the same time,
link |
01:11:58.040
at least from the perspective of metabolic health,
link |
01:12:00.080
because of the way that eating impacts these clock genes
link |
01:12:02.920
and impacts, or I should say,
link |
01:12:05.520
subtracts the sleep related fasting
link |
01:12:08.820
that you would normally experience
link |
01:12:10.400
if you were to finish eating
link |
01:12:12.720
a couple hours before bedtime.
link |
01:12:14.460
So again, we don't want to create any overly obsessive
link |
01:12:17.620
or neurotic focus on this.
link |
01:12:19.560
I think that most all people could benefit
link |
01:12:21.840
from a time-restricted feeding schedule,
link |
01:12:24.260
but they should really think hard
link |
01:12:25.360
about what they can stick to on a regular basis
link |
01:12:28.040
and understand that they tend to underestimate
link |
01:12:30.960
the feeding window that they actually are partaking in,
link |
01:12:34.240
and that they should place that feeding window
link |
01:12:37.720
in a portion of the 24 hour cycle
link |
01:12:39.600
that they can be consistent on most days.
link |
01:12:42.920
And I want to emphasize most,
link |
01:12:44.280
again, because we are not laboratory mice.
link |
01:12:46.580
We don't have a graduate student
link |
01:12:47.720
coming in for eight hours a day
link |
01:12:48.960
because that's what their significant other
link |
01:12:50.320
will allow them to do.
link |
01:12:51.160
And then removing the food from our jowls
link |
01:12:52.900
and from our cages,
link |
01:12:54.160
we have access to food pretty much 24 hours a day.
link |
01:12:58.240
Along those lines, however,
link |
01:12:59.860
there are things that we can all do
link |
01:13:02.660
that will allow us to offset some of the drift,
link |
01:13:07.320
if you will, that we experience
link |
01:13:09.200
or that we induce in terms of
link |
01:13:11.080
when our feeding window occurs
link |
01:13:12.560
or that the feeding window might push out a little later
link |
01:13:15.780
and then therefore start a little later the next day.
link |
01:13:18.500
There are things that we can do
link |
01:13:19.340
and there are things that we can take.
link |
01:13:20.540
And so I'd like to discuss those briefly.
link |
01:13:22.580
So throughout this episode,
link |
01:13:24.340
I've more or less been alluding to the fact
link |
01:13:27.360
that when you eat,
link |
01:13:29.240
there's some period of time afterwards
link |
01:13:30.760
in which you're actually still eating,
link |
01:13:32.760
at least from the perspective of metabolism,
link |
01:13:34.740
because glucose is up, insulin is up,
link |
01:13:37.520
and you're undergoing different metabolic
link |
01:13:40.040
and digestive processes that don't really speak to you
link |
01:13:43.880
being in a fasted state, right?
link |
01:13:46.120
It's not just about when you take your last bite
link |
01:13:48.460
or your last sip.
link |
01:13:49.560
However, there are things that we can do
link |
01:13:52.960
to accelerate the transition from a fed state
link |
01:13:56.800
to a fasted state.
link |
01:14:00.360
And so I'd like to discuss what those are.
link |
01:14:02.200
And I want to emphasize that the term fed state
link |
01:14:05.560
is probably a better way to think about it
link |
01:14:08.100
than eating or not eating,
link |
01:14:09.920
because we think of eating as the verb,
link |
01:14:11.700
we're eating, we're eating, okay, we're done eating,
link |
01:14:13.400
I'm fasting now,
link |
01:14:14.440
but you're not actually fasting because you are fed.
link |
01:14:18.120
So we should really think about fed and unfed states
link |
01:14:21.160
because from a cellular processes perspective
link |
01:14:23.460
and from a health perspective,
link |
01:14:24.920
that's actually what your body and your system
link |
01:14:27.400
are paying attention to.
link |
01:14:28.760
And by now with everything that we've laid out,
link |
01:14:31.320
I think that should be intuitive to understand.
link |
01:14:34.440
So there's a fun and exciting concept related to this,
link |
01:14:36.880
which is glucose clearing.
link |
01:14:39.500
You may have heard the old adage
link |
01:14:40.800
that if you take a 20 or 30 minute walk after dinner,
link |
01:14:44.760
that it accelerates the rate at which you digest that food.
link |
01:14:47.780
And indeed it does.
link |
01:14:49.660
Clearing out of glucose from your system
link |
01:14:52.560
can be accomplished through a number of different means,
link |
01:14:54.820
but light movement or exercise
link |
01:14:57.220
does increase gastric emptying time.
link |
01:14:59.880
So for instance,
link |
01:15:01.400
if you were to eat a meal that ended at 8 PM
link |
01:15:05.720
and then plop to the couch, watch TV,
link |
01:15:09.000
or get on your computer or go to sleep,
link |
01:15:12.680
it would be five or six hours until you have transitioned
link |
01:15:16.520
from a fed state to a fasted state.
link |
01:15:19.360
However, you can accelerate that considerably
link |
01:15:22.400
by taking a 20 or 30 minute, just light walk.
link |
01:15:25.840
It doesn't have to be speed walking.
link |
01:15:27.260
It certainly doesn't have to be jogging,
link |
01:15:28.440
but just walking outside or moving around.
link |
01:15:31.880
So glucose clearing is an important aspect of the transition
link |
01:15:36.520
from the fed state to the fasted state.
link |
01:15:38.860
And just a light walk can allow you to do that.
link |
01:15:41.300
Now, if you can't get outside,
link |
01:15:42.640
some people will go through the gymnastics literally
link |
01:15:46.600
of doing things like air squats and pushups
link |
01:15:48.800
and things like that.
link |
01:15:49.640
And indeed those will increase the expression of things
link |
01:15:52.200
like Glut4 and things that mobilize glucose into muscles
link |
01:15:56.480
and things of that sort.
link |
01:15:57.300
But, you know, under most conditions,
link |
01:15:59.400
most people aren't doing pushups after dinner,
link |
01:16:01.240
or certainly if you've had a big meal,
link |
01:16:03.120
just taking a light walk can be beneficial.
link |
01:16:06.120
In addition, you could consider doing intense exercise.
link |
01:16:11.120
Now you wouldn't necessarily want to do that
link |
01:16:12.960
immediately after eating.
link |
01:16:14.160
So let's take a look at what high intensity training
link |
01:16:17.360
of any kind does to blood glucose,
link |
01:16:19.800
because in this case,
link |
01:16:20.620
it turns out that when you do high intensity training
link |
01:16:23.360
actually has opposite effects on blood glucose,
link |
01:16:26.560
depending on whether or not you do it
link |
01:16:27.720
early or later in the day.
link |
01:16:29.840
So a fairly recent study looked at so-called HIIT training,
link |
01:16:33.020
high intensity interval training,
link |
01:16:34.880
which of course can take many different forms.
link |
01:16:37.000
It can take the form of circuit training with weights.
link |
01:16:39.580
It can take the form of, you know, burpees and pushups
link |
01:16:42.060
and sprints and all sorts of different things,
link |
01:16:44.120
but high intensity interval training is typically training
link |
01:16:47.000
that gets people's heart rates up, you know,
link |
01:16:49.480
well above 70% of maximum and then brief periods of rest
link |
01:16:54.160
and then repeating and how long the high intensity interval
link |
01:16:56.400
training of course will also vary.
link |
01:16:58.400
There are very brief, you know,
link |
01:17:00.640
six or 12 or 15 minute workouts.
link |
01:17:02.960
Some people can carry on with high intensity interval
link |
01:17:05.540
training for up to 45 or maybe even 60 minutes
link |
01:17:08.420
in extreme cases.
link |
01:17:09.360
But when you look at the studies that have explored high
link |
01:17:13.440
intensity interval training and its effect on blood glucose,
link |
01:17:16.720
there are a couple of studies that leap out.
link |
01:17:18.520
For instance,
link |
01:17:19.360
one that emphasize that blood glucose levels will actually
link |
01:17:22.120
increase if high intensity interval training is performed
link |
01:17:24.760
early in the day and will decrease if high intensity
link |
01:17:27.800
interval training is performed later in the day.
link |
01:17:31.000
Now the purpose for this exploration was not to explore
link |
01:17:36.760
clearance of blood glucose for sake of intermittent
link |
01:17:39.080
fasting.
link |
01:17:39.920
It was mainly focused on athletic performance and whether
link |
01:17:42.360
or not that was better early in the day or later in the day,
link |
01:17:44.360
et cetera.
link |
01:17:45.560
But we can extract some information from these studies that
link |
01:17:50.040
are beneficial for sake of understanding glucose clearing.
link |
01:17:54.000
If you have ingested food throughout the afternoon and
link |
01:17:58.080
evening and late in the day,
link |
01:17:59.120
and you're thinking about going to sleep and you'd like to
link |
01:18:01.800
enter sleep in a way that is less fed and more fasted,
link |
01:18:05.840
then engaging in high intensity interval training in the
link |
01:18:08.700
afternoon will lower or evening,
link |
01:18:11.240
I should say will lower blood glucose.
link |
01:18:14.040
And in that way will help you accelerate your transition
link |
01:18:16.640
into the fastest state provided you don't ingest something
link |
01:18:19.260
after the high intensity interval training.
link |
01:18:21.540
Now is the increase in blood glucose that occurs from high
link |
01:18:25.300
intensity interval training early in the day,
link |
01:18:27.560
is that detrimental?
link |
01:18:28.680
Not necessarily so that oftentimes is associated with the
link |
01:18:32.560
shuttling of nutrients to the muscles that have just done a
link |
01:18:34.840
lot of hard work.
link |
01:18:35.940
So it's not that high intensity interval training should not
link |
01:18:39.240
be done early in the day.
link |
01:18:40.380
In fact, for many people,
link |
01:18:41.320
including myself training early in the day,
link |
01:18:44.080
just for the way that my psychology and biology works is
link |
01:18:46.520
always better for me than training later in the day.
link |
01:18:49.040
And the other important thing to mention is that high
link |
01:18:51.700
intensity interval training done late in the day can be
link |
01:18:55.060
beneficial from the perspective of glucose clearing,
link |
01:18:58.520
lowering blood glucose and helping transition from the fed
link |
01:19:01.920
to the fasted state in preparation for sleep.
link |
01:19:04.920
However, if you're ingesting caffeine or anything to engage
link |
01:19:08.840
in that high intensity interval training in a way that
link |
01:19:10.920
prevents you from getting to sleep, well,
link |
01:19:12.800
then it's going to be detrimental overall.
link |
01:19:14.960
So the reason I mentioned this is of course,
link |
01:19:18.000
because it's nice to know that light walks after dinner or
link |
01:19:21.000
any other meal for that matter or high intensity interval
link |
01:19:23.640
training provided it's done in the second half of the day,
link |
01:19:25.800
can lower blood glucose and speed the transition from fed to
link |
01:19:29.880
fasted states.
link |
01:19:31.280
But I also mention it because what we are really trying to
link |
01:19:34.900
achieve when we partake in intermittent fasting,
link |
01:19:38.200
so-called time restricted feeding is what we're really
link |
01:19:40.900
trying to do is access unfed states or fasted states.
link |
01:19:45.920
It's not really about when you eat and what you do.
link |
01:19:48.480
It's about extending the duration of the fasting period,
link |
01:19:52.080
as long as you can,
link |
01:19:53.760
in a way that's still compatible with your eating, right?
link |
01:19:56.880
Not the other way around.
link |
01:19:58.760
And this gets back to this key feature of our biology,
link |
01:20:02.080
which is that what we eat, when we eat, when we exercise,
link |
01:20:05.960
when we view light,
link |
01:20:06.880
it's about setting a context or a set of conditions in your
link |
01:20:10.200
brain and body.
link |
01:20:11.460
So it's not so much about the activities that you undergo.
link |
01:20:14.220
It's about the activities you undergo and their
link |
01:20:16.840
relationship to one another over time.
link |
01:20:19.520
And so in this way,
link |
01:20:21.420
it really beautifully highlights the way that your biology is
link |
01:20:24.340
interacting all the time.
link |
01:20:25.560
Light is setting when you're going to be awake and when
link |
01:20:27.360
you're going to be asleep,
link |
01:20:28.600
when you eat is going to be determining when you're going to
link |
01:20:30.480
be awake and when you're going to be asleep and when you eat
link |
01:20:33.320
is also going to be determining when you are able to clear
link |
01:20:37.120
out debris from your brain and body and repair the various
link |
01:20:41.040
cells and mechanisms of your body,
link |
01:20:42.720
when you're able to reduce those inflammatory cytokines
link |
01:20:45.720
throughout your body.
link |
01:20:46.940
And this is really the beauty of time-restricted feeding,
link |
01:20:49.680
which is it's not really about restricting your feeding.
link |
01:20:52.560
It's about accessing the beauty of the fasted state.
link |
01:20:56.000
Now, there are other ways to clear out blood glucose that
link |
01:21:00.000
involve supplements or prescription drugs.
link |
01:21:02.740
These are so-called glucose disposal agents,
link |
01:21:06.400
glucose disposal agents, such as metformin,
link |
01:21:09.400
which is a prescription drug or berberine,
link |
01:21:12.480
which is an over the counter substance will lead to very
link |
01:21:15.920
dramatic reductions in blood glucose.
link |
01:21:18.440
And so they shift you from a fed to a fasted state.
link |
01:21:21.200
And I know many people who take berberine before eating
link |
01:21:26.000
meals that include a large number of carbohydrates,
link |
01:21:28.920
for instance, as a way to clear out glucose.
link |
01:21:32.100
Now I've tried berberine before.
link |
01:21:33.560
And what I can tell you is that if you take berberine,
link |
01:21:36.540
which by the way is very much like metformin,
link |
01:21:38.480
its effects are almost identical to metformin in fact,
link |
01:21:41.000
but it's much less expensive and it's over the counter.
link |
01:21:43.800
If you take berberine and you have not ingested
link |
01:21:46.200
carbohydrates, many people, including myself,
link |
01:21:49.500
experience a splitting headache.
link |
01:21:52.140
You become hypoglycemic because it is a glucose clearing
link |
01:21:55.560
agent.
link |
01:21:56.400
So if you're going to experiment with things like metformin
link |
01:21:58.880
and or berberine or similar,
link |
01:22:01.080
you want to be very cautious that you're not clearing out
link |
01:22:04.280
blood glucose that's already low.
link |
01:22:06.600
And the dose response for this varies tremendously from one
link |
01:22:10.280
individual to the next.
link |
01:22:11.600
And there's a strong circadian component.
link |
01:22:14.020
So some people react very well to berberine early in the
link |
01:22:17.200
day, but find that later in the day,
link |
01:22:19.040
it provides extreme headaches for some people,
link |
01:22:22.560
it's the opposite.
link |
01:22:23.680
So I caution you in exploring things like berberine and
link |
01:22:27.200
metformin that you should expect to experience a number of
link |
01:22:30.720
physical and psychological effects that may work for you,
link |
01:22:34.240
might be great for you, but might also not be great for you.
link |
01:22:37.160
Nowadays,
link |
01:22:38.000
there are a number of commercially available continuous
link |
01:22:40.280
glucose monitors.
link |
01:22:41.640
I've tried one of these.
link |
01:22:42.500
It involves putting what's essentially a patch with a little
link |
01:22:46.040
needle that goes into your skin,
link |
01:22:47.040
which is continuing continually, excuse me,
link |
01:22:49.280
monitoring your blood glucose.
link |
01:22:50.720
And you can look at it at an app on your phone.
link |
01:22:52.640
And you can learn a lot that way about how different foods
link |
01:22:55.040
impact the increases and decrease in blood glucose.
link |
01:22:58.680
If you're doing experiments with berberine or metformin,
link |
01:23:01.000
you can see how those impact your blood glucose.
link |
01:23:03.960
You can see how exercise hit training or otherwise impact
link |
01:23:07.240
impacts blood glucose.
link |
01:23:08.840
Excuse me again.
link |
01:23:10.960
It's very hard to assess blood glucose without a continuous
link |
01:23:14.360
blood glucose monitor.
link |
01:23:15.400
And if you're not using one,
link |
01:23:16.800
you're mainly going to be relying on subjective things like,
link |
01:23:19.560
oh, I feel like I have low blood sugar.
link |
01:23:21.800
I feel shaky.
link |
01:23:23.180
Like I have high blood sugar or shaky.
link |
01:23:24.600
Cause you have low blood sugar.
link |
01:23:25.600
So I have to say that glucose clearing agents that involve
link |
01:23:30.600
a walk or exercise moderate or intense are going to be a lot
link |
01:23:35.500
easier to titrate and adjust the levels of than things that
link |
01:23:39.320
you're going to take where you have to ingest the dosage.
link |
01:23:41.520
And then once you ingest a certain dosage,
link |
01:23:43.740
you're along for the ride,
link |
01:23:44.800
at least until the effects of that particular compound wear
link |
01:23:47.260
off, it doesn't mean those things don't have utility.
link |
01:23:49.440
It doesn't mean people aren't using them because many
link |
01:23:51.420
people are,
link |
01:23:52.260
but they are potentially a very sharp blade.
link |
01:23:57.120
That is a double sided blade.
link |
01:23:58.900
So I encourage you to approach those with caution.
link |
01:24:01.020
If you decide to at all,
link |
01:24:03.060
it's worth thinking about what the low blood glucose state
link |
01:24:06.520
is and why it's beneficial as well as why it might produce
link |
01:24:10.600
headaches.
link |
01:24:11.440
And in some cases can also adjust the effects of other
link |
01:24:13.700
hormones in the fasted state.
link |
01:24:16.040
A number of different proteins that are expressed in cells
link |
01:24:20.180
undergo changes in their expression.
link |
01:24:21.840
We talked about this earlier.
link |
01:24:23.380
When we are fasted,
link |
01:24:24.980
we tend to reduce the activity of a particular protein
link |
01:24:28.540
called mTOR mammalian target of rapamycin mTOR is very
link |
01:24:33.220
active in cells while they are growing.
link |
01:24:35.420
So throughout development,
link |
01:24:37.100
it's also very active in cancers of various kinds.
link |
01:24:41.380
mTOR needs to be what's called phosphorylated.
link |
01:24:44.340
If you don't know what that means, don't worry about it.
link |
01:24:45.900
But phosphorylation is a manner in which certain proteins
link |
01:24:49.620
are altered so that they can actually be functional within
link |
01:24:52.300
cells.
link |
01:24:53.500
mTOR is associated with cell growth of all kinds,
link |
01:24:55.460
healthy and unhealthy.
link |
01:24:58.480
When mTOR is phosphorylated, there's a marker called PS6.
link |
01:25:02.460
So phospho mTOR expresses PS6.
link |
01:25:05.540
If this is all escaping you, don't worry about it.
link |
01:25:08.320
Phospho mTOR and PS6 are reduced by fasting.
link |
01:25:12.460
Now this makes sense if you think about it,
link |
01:25:14.180
because eating and growth are associated with each other.
link |
01:25:17.300
Fasting is not necessarily anti-growth,
link |
01:25:21.980
but it is not pro-growth.
link |
01:25:23.500
And when we fast, we see increases in cells of things like
link |
01:25:26.900
AMPK, the sirtuins, things like transcription factors,
link |
01:25:31.160
like FOXO, ATF and ketones or ketone bodies.
link |
01:25:34.720
You may have heard of the ketogenic diet.
link |
01:25:36.620
What's the point of all this biochemistry.
link |
01:25:38.160
It's not to just blitz you with a bunch of cellular biology
link |
01:25:41.440
and biochemistry.
link |
01:25:42.660
It's to say that we have cell growth pathways involving
link |
01:25:45.140
mTOR and PS6, and we have cell repair
link |
01:25:50.240
and cell shrinkage processes that are associated with AMPK,
link |
01:25:54.980
the so-called sirtuins,
link |
01:25:56.060
which Dr. David Sinclair from Harvard and others are famous
link |
01:25:59.180
for discovering and understanding things like AMPK.
link |
01:26:04.100
These two different divergent pathways of cell growth
link |
01:26:07.060
and cell breakdown and repair.
link |
01:26:10.180
And by breakdown, I mean actual clearance,
link |
01:26:12.260
autophagy and repair.
link |
01:26:14.980
Those can be triggered by being in either the fed
link |
01:26:17.700
or the fasted state.
link |
01:26:18.980
So one way I'd like you to think about the fed state,
link |
01:26:21.680
not just eating, but having recently eaten
link |
01:26:24.540
or the fasted state, meaning high blood glucose
link |
01:26:27.940
and or you've recently eaten or are currently eating
link |
01:26:31.980
or drinking calories is that when you eat
link |
01:26:34.780
or when you don't eat, when you're fed,
link |
01:26:36.300
when you're fasted,
link |
01:26:37.140
you are either promoting cellular growth of all kinds
link |
01:26:40.180
or you're promoting cellular repair
link |
01:26:42.640
and clearance of all kinds.
link |
01:26:44.460
And so, again, this is about setting conditions
link |
01:26:46.860
in the brain and body.
link |
01:26:48.300
It's not so much about when you eat food A or B,
link |
01:26:52.440
it leads to increases in mTOR.
link |
01:26:55.000
Anytime you eat any food,
link |
01:26:56.860
doesn't matter if it's plant-based, animal-based, fat,
link |
01:26:59.940
protein, carbohydrate, doesn't matter.
link |
01:27:01.840
You are biasing your system towards a biochemical state
link |
01:27:04.960
of cell growth.
link |
01:27:05.840
And anytime you haven't eaten for a while
link |
01:27:08.300
or blood glucose is low,
link |
01:27:10.080
you're biasing your system toward a state of cellular repair.
link |
01:27:13.900
And this is why people who do not suffer
link |
01:27:17.480
from any blood glucose regulation issues,
link |
01:27:20.300
take things like berberine as glucose disposal agents
link |
01:27:23.080
or take metformin.
link |
01:27:23.920
I'm not necessarily suggesting that you do that,
link |
01:27:26.380
but it's because those things mimic fasting.
link |
01:27:29.180
They create situations in the body that promote things
link |
01:27:32.060
like AMPK and the sirtuins and others to push your body
link |
01:27:35.540
and your system down a route of repair,
link |
01:27:37.820
even though you might've just eaten a meal an hour ago.
link |
01:27:40.660
Along the lines of the health benefits
link |
01:27:42.540
of intermittent fasting,
link |
01:27:44.300
there are nice data showing improvements
link |
01:27:46.820
in the gut microbiome.
link |
01:27:49.300
And in particular,
link |
01:27:51.000
in the treatment of irritable bowel syndrome
link |
01:27:53.420
and other forms of colitis in time-restricted feeding,
link |
01:27:57.640
meaning time-restricted feeding seems to be able
link |
01:28:00.020
to assist people with those conditions
link |
01:28:02.980
following the general parameters that I discussed before,
link |
01:28:05.420
eight hours and so forth.
link |
01:28:07.660
Why and how?
link |
01:28:08.700
Well, by way of intermittent fasting,
link |
01:28:11.700
impacting the expression of these various clock genes
link |
01:28:14.100
and because the clock genes impact the mucosal lining,
link |
01:28:17.280
the mucus lining of the gut,
link |
01:28:19.540
it appears that intermittent fasting
link |
01:28:22.860
can reduce the amount of so-called lactobacillus
link |
01:28:26.340
that's present in the gut.
link |
01:28:28.000
And lactobacillus is when in high levels is correlated
link |
01:28:31.840
with a number of different metabolic disorders.
link |
01:28:34.300
At the same time,
link |
01:28:35.160
time-restricted feeding seems to enhance the proliferation
link |
01:28:38.540
of some of the gut microbiota like oscillobacter
link |
01:28:42.740
and some of the other ones
link |
01:28:43.900
that promote healthy mucosal lining
link |
01:28:46.540
and that promote better overall intestinal function.
link |
01:28:50.480
So these are pathways that have now been established
link |
01:28:53.380
and it appears that intermittent fasting
link |
01:28:55.060
isn't just modulating these processes,
link |
01:28:57.360
but is actually having a direct effect
link |
01:28:58.940
on the mucosal lining in a way
link |
01:29:00.180
that favors a healthier gut microbiome.
link |
01:29:02.740
So it should come as no surprise
link |
01:29:04.420
that many people who experience gut issues benefit
link |
01:29:07.040
from restricting their feeding window
link |
01:29:08.720
to eight hours or so per every 24 hour period.
link |
01:29:11.700
The other very exciting finding about intermittent fasting
link |
01:29:14.420
is one of the major health issues these days
link |
01:29:17.260
is the proliferation of so-called
link |
01:29:20.480
non-alcoholic fatty liver disease.
link |
01:29:23.420
30 years or so non-alcoholic fatty liver disease
link |
01:29:26.300
was exceedingly rare to see in the clinic,
link |
01:29:28.260
except in alcoholics.
link |
01:29:30.580
Fatty deposits in the liver are bad.
link |
01:29:32.600
It is essentially liver disease.
link |
01:29:34.900
Nowadays, children and adults are showing up
link |
01:29:38.140
with non-alcoholic fatty liver disease.
link |
01:29:40.180
Some of these people are obese, others are not,
link |
01:29:42.940
but it's a serious health concern
link |
01:29:44.700
and it's growing in numbers all the time.
link |
01:29:48.040
A recent study that was published in Cell Reports Medicine
link |
01:29:51.700
just a couple of weeks ago tested the hypothesis
link |
01:29:54.860
whether or not the gut microbiome
link |
01:29:57.340
or so-called brown fat tissue is impacting the liver health
link |
01:30:01.780
and in particular non-alcoholic fatty liver disease.
link |
01:30:06.020
The short takeaway from this study is that
link |
01:30:07.940
contrary to what was previously thought,
link |
01:30:10.260
the gut microbiome, while very important
link |
01:30:12.660
for a number of other processes in the body,
link |
01:30:15.420
doesn't seem to be related
link |
01:30:16.920
to this non-alcoholic fatty liver disease.
link |
01:30:18.900
This is surprising to people or should be
link |
01:30:20.960
to those of you that have been following
link |
01:30:22.360
the gut microbiome literature.
link |
01:30:23.660
However, brown fat, which is a healthy fat
link |
01:30:27.860
that we have between our two scapulae and in our upper neck,
link |
01:30:30.740
it doesn't tend to be blubbery type fat pads,
link |
01:30:32.860
but it sits deep to the skin,
link |
01:30:34.580
but creates a thermogenic effect in the body
link |
01:30:37.900
that is helpful for reducing the amount of other fat,
link |
01:30:41.480
the type of fat that we're more typically used to thinking
link |
01:30:43.900
about and talking about white fat and pink fat
link |
01:30:45.700
that's subcutaneous fat around the abdomen and so forth.
link |
01:30:49.860
Brown fat seems to have a direct correlation
link |
01:30:52.980
with the lack of non-alcoholic fatty liver disease.
link |
01:30:55.580
What this study showed was that
link |
01:30:57.740
in people that have diminished concentrations of brown fat,
link |
01:31:02.940
there is a higher probability
link |
01:31:05.760
of having non-alcoholic fatty liver disease.
link |
01:31:07.820
Now, the good news is brown fat stores can be increased.
link |
01:31:10.680
And again, this isn't going to create blubber of brown fat.
link |
01:31:13.260
This is going to create increased thermogenesis
link |
01:31:15.060
and actually make people leaner.
link |
01:31:17.220
And brown fat has a number
link |
01:31:18.180
of other important positive effects.
link |
01:31:20.500
Now, this is interesting because cold exposure
link |
01:31:23.440
of anywhere from one to three minutes,
link |
01:31:25.660
two or four times per week, or maybe even 10 minutes,
link |
01:31:27.660
two to four times per week can increase brown fat stores.
link |
01:31:31.140
Also time-restricted feeding has now been tied
link |
01:31:34.540
to the density of brown fat stores.
link |
01:31:37.600
So time-restricted feeding also seems
link |
01:31:39.480
to positively increase brown fat stores,
link |
01:31:42.100
probably because of the way that brown fat stores relate
link |
01:31:44.300
to epinephrine and adrenaline,
link |
01:31:45.820
which tend to go up when we're fasted.
link |
01:31:48.220
What does this all mean?
link |
01:31:49.140
This means for sake of liver health
link |
01:31:51.640
and for sake of reducing or maybe preventing
link |
01:31:54.500
or even potentially,
link |
01:31:56.280
want to underline potentially reversing
link |
01:31:57.740
non-alcoholic fatty liver disease,
link |
01:31:59.940
time-restricted feeding also appears to be beneficial.
link |
01:32:03.380
Many people out there are interested
link |
01:32:05.040
in optimizing their hormones.
link |
01:32:07.540
And as we mentioned earlier, insulin is a hormone
link |
01:32:09.820
and time-restricted feeding seems
link |
01:32:11.620
to have very positive effects
link |
01:32:12.900
on overall insulin profiles and so forth.
link |
01:32:15.980
But anytime you mention hormones,
link |
01:32:18.620
people immediately seem to leap to the sex steroid hormones,
link |
01:32:21.400
testosterone and estrogen,
link |
01:32:23.220
because indeed they have powerful effects,
link |
01:32:24.900
both in the short-term and the long-term in terms
link |
01:32:28.040
of our mental and physical health and performance.
link |
01:32:31.120
There's at least one study that's explored the effects
link |
01:32:33.660
of time-restricted eating on performance,
link |
01:32:36.780
athletic performance, immune function,
link |
01:32:38.780
and body composition.
link |
01:32:40.620
This was a study by Morrow et al
link |
01:32:43.060
that was performed on elite cyclists.
link |
01:32:45.060
So I want to point that out.
link |
01:32:46.660
It was a randomized control trial,
link |
01:32:49.420
but what's really nice about this study is
link |
01:32:51.740
that it explored a number of different hormonal parameters
link |
01:32:57.620
in people that were using time-restricted eating
link |
01:32:59.640
or that had a more extended eating window.
link |
01:33:02.180
And they tracked everything very carefully.
link |
01:33:04.540
And the amount of food they were eating
link |
01:33:06.980
was actually pretty considerable, 4,800 calories.
link |
01:33:10.260
So that's a lot of calories,
link |
01:33:11.820
but then again, they were very active.
link |
01:33:13.960
And they've measured a number
link |
01:33:15.900
of different things related to VO2 max, et cetera.
link |
01:33:18.940
Performance and overall performance at what they did,
link |
01:33:23.580
cycling is not the point that I want to emphasize here.
link |
01:33:26.860
Although there were some positive effects
link |
01:33:28.900
on their performance related to time-restricted eating.
link |
01:33:32.020
The point I want to talk about relates to things
link |
01:33:35.960
that presumably relate to most everybody,
link |
01:33:38.320
which are the effects on things like glucose,
link |
01:33:41.980
thyroid hormone, testosterone,
link |
01:33:44.380
sex hormone binding globulin,
link |
01:33:45.860
which can bind up testosterone and prevent
link |
01:33:48.960
the so-called free form of testosterone,
link |
01:33:50.960
which is the one that has most of the actions
link |
01:33:53.340
in the brain and body.
link |
01:33:55.120
And the major takeaway from this study
link |
01:33:57.460
was that time-restricted feeding
link |
01:33:59.900
of the same amount of calories
link |
01:34:02.260
as the so-called control condition, okay?
link |
01:34:04.700
Same calories, but either compact
link |
01:34:06.740
throughout the 24 hour cycle to an eight hour feeding window
link |
01:34:10.020
or allowing them to eat over a larger feeding window
link |
01:34:13.780
did lead to significant decreases in free testosterone.
link |
01:34:18.060
And I think a number of people will raise their eyebrows
link |
01:34:20.540
to that and think, oh,
link |
01:34:21.740
well then maybe time-restricted feeding is not for me.
link |
01:34:24.100
There are a number of important considerations, of course.
link |
01:34:26.140
One is while the decrease in free testosterone
link |
01:34:30.340
was significant,
link |
01:34:31.660
it's also going to depend on where people start out.
link |
01:34:33.960
So if somebody has already low or modest levels
link |
01:34:36.980
of testosterone and it drops by 10 or 20%,
link |
01:34:39.900
that could lead them into a state of poor performance
link |
01:34:43.080
and wellbeing.
link |
01:34:43.920
Whereas if somebody has higher testosterone,
link |
01:34:45.980
a decrease won't necessarily do that.
link |
01:34:47.880
So it's important to take that into consideration.
link |
01:34:50.080
This is why I'm always such a fan
link |
01:34:51.300
of people doing their blood work
link |
01:34:53.480
and knowing what's going on under the hood for them.
link |
01:34:56.520
A very interesting change in hormonal profile
link |
01:34:59.500
was cortisol, so-called stress hormone.
link |
01:35:02.220
Cortisol, of course,
link |
01:35:03.060
is also naturally released early in the day
link |
01:35:05.180
in a healthy way to wake you up and promote alertness,
link |
01:35:08.300
but you don't want its levels to be too high
link |
01:35:10.820
or to have peaks in cortisol late in the day.
link |
01:35:13.620
It's actually correlated with depression
link |
01:35:15.040
and a number of other untoward things.
link |
01:35:19.700
I would have thought that by restricting a feeding window
link |
01:35:22.140
to a particular time each day,
link |
01:35:24.420
that these hard training cyclists
link |
01:35:26.180
would have undergone increases in serum cortisol.
link |
01:35:29.380
And in fact, the opposite was true.
link |
01:35:32.020
They had significant reductions in serum cortisol
link |
01:35:35.680
as a consequence of time-restricted feeding.
link |
01:35:37.680
I should mention there were significant reductions
link |
01:35:39.580
in serum cortisol also in the control group,
link |
01:35:42.680
but not to the same extent.
link |
01:35:44.660
And the two groups did differ significantly
link |
01:35:46.660
from one another.
link |
01:35:48.060
Now, this is important because if you just look
link |
01:35:50.680
at one hormone, testosterone, you'd say,
link |
01:35:52.800
okay, based on these data, time-restricted feeding
link |
01:35:55.860
is reducing testosterone levels significantly,
link |
01:35:58.520
even though the number of calories is quite high
link |
01:36:00.540
and is held constant across the study.
link |
01:36:02.540
But in fact, because cortisol is lower,
link |
01:36:05.660
it may mean that the effects of testosterone
link |
01:36:08.140
or the reduction in testosterone is offset.
link |
01:36:10.260
And that's because cortisol and testosterone
link |
01:36:12.500
are always in this somewhat of a dance
link |
01:36:14.900
in terms of cortisol inhibiting the effects
link |
01:36:17.300
of testosterone largely and vice versa.
link |
01:36:20.160
So it is interesting and important
link |
01:36:22.100
to look at the total gallery of hormones.
link |
01:36:24.380
And they did look at a number of hormones.
link |
01:36:26.700
They looked at other inflammatory markers.
link |
01:36:28.500
Those were not increased.
link |
01:36:29.720
That's not surprising.
link |
01:36:30.740
If you remember back to the 2012 Sachin Panda study,
link |
01:36:33.740
this early pioneering study on time-restricted feeding,
link |
01:36:36.980
they saw reductions in stress hormones
link |
01:36:39.580
and in inflammatory markers
link |
01:36:41.100
in time-restricted feeding mice.
link |
01:36:43.380
And here, this also seems to be the case in humans.
link |
01:36:46.200
So the takeaway is for sake of hormone health,
link |
01:36:50.420
time-restricted feeding is compatible
link |
01:36:53.900
with quality hormone health,
link |
01:36:55.520
even in high-performing athletes.
link |
01:36:57.940
Based on everything we know and that we've discussed,
link |
01:36:59.900
I would not suggest that people restrict
link |
01:37:01.780
their feeding window to less than eight hours,
link |
01:37:03.740
especially if they're training hard on a regular basis.
link |
01:37:06.500
And it's not just athletes that should pay attention to this
link |
01:37:10.820
when we are working very hard,
link |
01:37:12.260
when we are psychologically stressed,
link |
01:37:14.300
when we are studying for exams,
link |
01:37:16.960
or we are in conflict with somebody on a regular basis,
link |
01:37:20.980
that creates a stress in the body
link |
01:37:22.880
that's very similar to that of physical training.
link |
01:37:25.420
The body and brain don't distinguish
link |
01:37:26.840
between physical stress and mental stress.
link |
01:37:28.580
It's all nervous system.
link |
01:37:29.700
Remember that it's just cortisol and adrenaline.
link |
01:37:32.020
There's no special hormone just for physical stress
link |
01:37:35.400
versus psychological stress.
link |
01:37:37.220
So again, in thinking about what sort of feeding window
link |
01:37:39.940
will be right for you,
link |
01:37:40.780
we arrive back at this eight-hour time bin
link |
01:37:43.960
that seems more or less flexible for most conditions,
link |
01:37:47.660
even high-performing elite athletes.
link |
01:37:49.700
And I would say just by logical extension,
link |
01:37:52.740
even for people that have a lot of stress in their life.
link |
01:37:55.060
And I personally wouldn't suggest
link |
01:37:57.580
that people who have a lot of stress in their life
link |
01:37:59.320
or the potential for stress in their life
link |
01:38:01.260
shorten their feeding window much shorter than eight hours,
link |
01:38:05.540
because then you would expect
link |
01:38:07.500
that you would start to increase
link |
01:38:08.880
some of the inflammatory markers.
link |
01:38:10.380
You would increase the stress hormones
link |
01:38:12.180
and you would be decreasing things like testosterone
link |
01:38:15.820
and estrogen and some of the sex steroid hormones.
link |
01:38:17.700
So again, it's all about context and the eight-hour window.
link |
01:38:20.500
It isn't holy, but seems to be a really useful guide
link |
01:38:23.200
to extract the great health benefits
link |
01:38:26.700
of which there are many and of which we've discussed
link |
01:38:29.680
from intermittent fasting, time-restricted feeding,
link |
01:38:33.760
and yet that it could still be compatible
link |
01:38:35.900
with decent social schedules
link |
01:38:37.620
and for maintaining hormone health.
link |
01:38:40.080
In keeping with this,
link |
01:38:41.380
for women that are trying to maintain ovulatory cycles
link |
01:38:44.060
or for couples that are trying to get pregnant,
link |
01:38:46.760
I think it's also important
link |
01:38:48.340
to not create a feeding window that's too short.
link |
01:38:52.500
The relationship between feeding and body fat stores
link |
01:38:56.760
and glucose and leptin and hormones
link |
01:38:59.580
is a well-established one.
link |
01:39:00.680
And we can summarize it very easily here,
link |
01:39:02.300
although I've done several episodes
link |
01:39:03.580
related to this previously on optimizing hormone health.
link |
01:39:06.560
But basically, we undergo puberty
link |
01:39:09.400
when there's enough food and there's enough body fat
link |
01:39:13.540
that the body fat sends a signal to the brain called leptin,
link |
01:39:16.300
that's a hormone that comes from body fat,
link |
01:39:17.860
signals to the brain to turn on puberty.
link |
01:39:20.940
That's puberty, but even as adults,
link |
01:39:23.500
for women that are menstruating,
link |
01:39:25.140
there needs to be sufficient leptin signaling to the brain
link |
01:39:27.940
in order to maintain ovulation
link |
01:39:29.340
because of the way that the brain communicates
link |
01:39:31.020
with the pituitary and the ovaries.
link |
01:39:32.800
Similarly, for men,
link |
01:39:36.180
fasting or extreme exercise plus fasting,
link |
01:39:40.020
we now know reduces testosterone.
link |
01:39:43.300
Its impacts are not exactly clear.
link |
01:39:45.700
However, if you reduce food intake,
link |
01:39:48.480
either in total calories or in duration too much,
link |
01:39:52.080
you will suffer a drop in sperm counts, fertility will drop.
link |
01:39:55.720
And this makes sense.
link |
01:39:56.560
The body is communicating to the brain
link |
01:39:58.140
whether or not conditions are sufficient in the body
link |
01:40:01.380
to reproduce and to presumably and hopefully support
link |
01:40:05.820
the health and wellbeing of those offspring.
link |
01:40:08.040
So there's a logical link between body fat and eating
link |
01:40:10.940
and how much food is available to you
link |
01:40:13.380
and how long it's available to you
link |
01:40:15.180
and the signals in the brain
link |
01:40:16.220
that allow for reproductive success.
link |
01:40:18.460
There are some data that pointed differences
link |
01:40:20.980
in the effects of intermittent fasting
link |
01:40:22.820
for males versus females.
link |
01:40:25.460
Those data right now only come from mice.
link |
01:40:28.020
That study was published by Sachin Panda recently.
link |
01:40:30.420
We still await the studies in humans.
link |
01:40:33.580
Some people do not do well on intermittent fasting,
link |
01:40:36.380
either in terms of mood or hormone health.
link |
01:40:38.820
And so everyone needs to determine for themselves
link |
01:40:40.720
whether or not having a time-restricted feeding window
link |
01:40:43.540
is good for them,
link |
01:40:44.640
how long that time-restricted feeding window should be.
link |
01:40:47.080
I think eight hours is kind of a nice minimum to adhere to
link |
01:40:50.280
based on everything that we've covered today.
link |
01:40:52.220
And for some people,
link |
01:40:54.800
time-restricted feeding is not going to be compatible
link |
01:40:57.020
with hormone health for them.
link |
01:40:58.140
For them, eating more meals spread throughout the day,
link |
01:41:01.720
presumably smaller meals, same caloric intake,
link |
01:41:04.540
is going to be more beneficial for their hormones.
link |
01:41:06.740
This is something that is going to be individual
link |
01:41:08.620
and is going to have to be determined
link |
01:41:10.760
on an individual basis.
link |
01:41:11.940
However, if you're going to try time-restricted feeding,
link |
01:41:15.220
I do want to remind you that taking a period of three to seven
link |
01:41:17.980
or ideally 10 days to transition into it,
link |
01:41:20.060
not just going flipping from eating to three meals a day
link |
01:41:23.300
that span from 6 a.m. to 10 p.m.
link |
01:41:25.160
and suddenly going to an eight-hour feeding window,
link |
01:41:27.140
but rather winnowing down that feeding window
link |
01:41:30.440
about an hour or so per day
link |
01:41:32.380
is going to allow the hormone systems of your body,
link |
01:41:34.640
including leptin, the hypocretin-erexin system,
link |
01:41:37.420
which are systems within the body that signal to the brain
link |
01:41:39.540
that food is about to come,
link |
01:41:41.380
allowing those systems to adjust
link |
01:41:43.220
so that you're not overwhelmingly hungry, irritable,
link |
01:41:46.180
and you're not throwing your whole hormone system
link |
01:41:48.420
out of whack.
link |
01:41:49.720
I keep coming back to this eight-hour feeding window
link |
01:41:52.020
and I want to provide a little more basis for it
link |
01:41:54.200
and just to encourage that it's not completely arbitrary.
link |
01:41:58.980
The lengthy review that I mentioned earlier
link |
01:42:01.120
features a number of studies
link |
01:42:02.380
that have used this eight-hour feeding window.
link |
01:42:05.220
But there's a particular study that I'd like to highlight,
link |
01:42:08.240
mainly because I don't expect people to delve
link |
01:42:09.820
into the full reference list of the other review.
link |
01:42:12.900
And this is a study that was carried out
link |
01:42:15.020
between Sachin Panda's lab and Christopher Verity's lab.
link |
01:42:18.300
So this is a collaboration.
link |
01:42:19.740
The study was carried out in humans
link |
01:42:21.420
and is entitled effects of eight-hour time-restricted feeding
link |
01:42:24.580
on body weight and metabolic disease risk factors
link |
01:42:27.400
in obese adults, excuse me.
link |
01:42:30.260
And this study essentially showed,
link |
01:42:32.660
I'll just read the conclusions,
link |
01:42:34.780
that an eight-hour time-restricted feeding
link |
01:42:37.740
produces a mild caloric restriction and weight loss
link |
01:42:42.100
without calorie counting.
link |
01:42:43.700
So that's key, right?
link |
01:42:45.020
These people aren't calorie counting.
link |
01:42:46.340
Somehow just by adhering to an eight-hour window,
link |
01:42:49.360
they are taking in fewer calories than they're burning off
link |
01:42:54.700
and clinically it reduced blood pressure.
link |
01:42:57.860
So I mentioned the study,
link |
01:42:58.840
not because there aren't many others
link |
01:43:00.340
involving the eight-hour feeding window, also in humans,
link |
01:43:03.220
but because the eight-hour feeding window has been tested
link |
01:43:06.020
in obese adults and non-obese adults.
link |
01:43:07.820
And there are even a few studies in children.
link |
01:43:10.420
So this eight-hour window seems to be
link |
01:43:12.220
a really good rule of thumb and a kind of anchor
link |
01:43:15.140
around which we can each think about
link |
01:43:17.980
incorporating time-restricted feeding.
link |
01:43:19.900
There are, of course, other patterns of feeding.
link |
01:43:22.180
And while some people have engaged in longer fasts
link |
01:43:26.520
of 24 hours, 36 hours, or more,
link |
01:43:32.020
alternate day fasting, meaning eating one day,
link |
01:43:35.200
not eating the next day, or in some cases eating one day
link |
01:43:37.820
and eating very few calories,
link |
01:43:39.340
500 or 600 calories the next day, has been tested.
link |
01:43:43.420
A few studies have also looked at eating
link |
01:43:46.140
a sort of maintenance level of calories for five days
link |
01:43:48.380
and then taking two days and fasting clear through
link |
01:43:52.080
or eating very few calories, 300 or 500 calories.
link |
01:43:55.860
In fact, there's a sort of a community online
link |
01:43:59.380
of people that are exploring longer fasts
link |
01:44:01.260
for sake of trying to offset dementia
link |
01:44:03.220
or reverse effects of dementia.
link |
01:44:05.500
Thus far, at least in my awareness,
link |
01:44:08.580
there isn't any quality clinical peer-reviewed study
link |
01:44:12.220
on that yet for sake of dementia.
link |
01:44:14.820
Although I await those studies
link |
01:44:16.020
and if anyone's aware of them,
link |
01:44:17.540
please send me a link in the comments.
link |
01:44:19.740
But alternate day fasting has gotten
link |
01:44:22.740
the so-called safe bill of health.
link |
01:44:24.540
This has been written up,
link |
01:44:25.680
meaning that people didn't suffer bone loss.
link |
01:44:27.460
They didn't suffer any major detrimental effects.
link |
01:44:31.260
It does seem that it can create significant weight loss
link |
01:44:35.940
and can help with obese individuals,
link |
01:44:38.600
that it can reduce resting blood glucose.
link |
01:44:40.820
And every other day fasting, in many cases,
link |
01:44:43.300
can produce more rapid effects on weight loss
link |
01:44:46.200
and reductions in blood glucose than time-restricted feeding.
link |
01:44:49.380
However, every other day type fasting,
link |
01:44:52.960
for most people, is not going to be feasible.
link |
01:44:56.120
They're just not going to be able to do that
link |
01:44:57.540
for a long period of time.
link |
01:44:58.480
And what hasn't really been done is the follow-up,
link |
01:45:00.720
to see whether or not people who do every other day fasting
link |
01:45:03.340
or five days of eating followed by two days of fasting,
link |
01:45:06.120
whether or not that leads to a rebound in weight gain,
link |
01:45:08.740
whether or not that leads to a rebound
link |
01:45:10.140
in blood glucose, et cetera.
link |
01:45:11.740
So for now, the eight-hour feeding window
link |
01:45:13.980
and time-restricted feeding seems to be the most tested,
link |
01:45:19.680
supported in animal studies and in human studies,
link |
01:45:22.420
and the one around which I think most people should orient
link |
01:45:25.660
if they're considering getting into time-restricted feeding.
link |
01:45:28.240
It's also sort of hard to imagine how one could include
link |
01:45:31.860
a significant exercise schedule or work schedule
link |
01:45:35.760
on every other day fasting.
link |
01:45:37.100
Remember, in any study, people are often being compensated,
link |
01:45:40.300
or at least are incentivized in some way
link |
01:45:42.980
to adhere to the study.
link |
01:45:44.860
This is one of the major issues that I have with any study
link |
01:45:47.300
that says that three or four different diets
link |
01:45:49.540
are essentially equal in terms of their ability
link |
01:45:52.600
to produce weight loss.
link |
01:45:54.080
Adherence is very different in the outside world,
link |
01:45:57.200
where you don't have a researcher monitoring you,
link |
01:45:59.300
where you're not logging all your food.
link |
01:46:01.120
Most people don't do that consistently.
link |
01:46:03.260
And we can take a little bit of a neuroscience perspective
link |
01:46:05.400
on this to try and arrive at what the best kind
link |
01:46:07.580
of organization of an eating plan, or if we wanted
link |
01:46:10.980
to call it a diet, we could, would be for you.
link |
01:46:14.680
Many people find it easier to just not eat
link |
01:46:17.380
for certain periods of each 24-hour cycle
link |
01:46:20.060
than to eat smaller portions.
link |
01:46:21.620
Portion control is very hard for some people.
link |
01:46:24.500
For other people, it's manageable.
link |
01:46:26.980
But people like me, I don't eat half the croissant.
link |
01:46:30.620
I don't think it's a real thing.
link |
01:46:32.260
It's not available to me, I should say.
link |
01:46:35.300
Now, of course I could eat just half a croissant.
link |
01:46:38.100
But I noticed that when I eat the croissant,
link |
01:46:39.740
because they're so delicious,
link |
01:46:41.300
that it creates a rise in blood glucose,
link |
01:46:43.660
a rise in the other hormones and chemicals
link |
01:46:46.480
that are associated with ingesting delicious,
link |
01:46:48.420
highly palatable food.
link |
01:46:50.120
And it's actually a lot of work for me
link |
01:46:52.220
to just eat half the croissant.
link |
01:46:54.500
There's something that's much more thoroughly satisfying
link |
01:46:58.860
about eating the entire croissant.
link |
01:47:00.660
And actually, there's something that's somewhat satisfying
link |
01:47:03.360
about not eating the croissant at all,
link |
01:47:05.120
and just knowing that later I can eat the whole croissant.
link |
01:47:07.380
Now that's me.
link |
01:47:08.360
Other people find that they don't have any trouble
link |
01:47:11.560
with portion control.
link |
01:47:13.000
That for them, just eating small bits of food
link |
01:47:14.820
throughout the day is what sets them
link |
01:47:16.340
in the right psychological and physical state
link |
01:47:18.600
for sake of work, et cetera.
link |
01:47:20.020
And I mentioned work and mental focus
link |
01:47:22.020
because one of the aspects of fasting
link |
01:47:24.340
that have drawn a lot of people
link |
01:47:26.060
to time-restricted feeding and fasting
link |
01:47:28.320
is the clarity of mind that people get
link |
01:47:31.460
when, first of all, they don't have to think about
link |
01:47:34.000
when they're going to eat
link |
01:47:34.840
because they know when their eating window begins.
link |
01:47:37.340
They also don't have to think about regulating
link |
01:47:39.220
their behavior because they already know
link |
01:47:42.340
when they're going to eat and when they're not going to eat.
link |
01:47:44.200
Whereas when you're restricting portions,
link |
01:47:46.300
you actually have to make decisions all the while.
link |
01:47:48.940
You know, and I think I, like many people decide,
link |
01:47:51.280
well, you know, is that exactly half
link |
01:47:53.380
or could I have like another rung on the croissant,
link |
01:47:55.580
this kind of thing.
link |
01:47:56.420
I don't negotiate with food.
link |
01:47:57.700
That's why I like a time-restricted feeding window.
link |
01:48:00.440
I know I'm going to eat for, in my case,
link |
01:48:01.900
I use a 10-hour feeding window or so.
link |
01:48:04.420
And I'll eat the whole croissant.
link |
01:48:05.780
I just don't have to think about it.
link |
01:48:07.820
Now, the food choices that you make
link |
01:48:10.140
inside of that feeding window are of course
link |
01:48:11.840
also going to be very important.
link |
01:48:13.260
Certain foods will increase blood glucose
link |
01:48:15.080
such that you're going to get hungrier and hungrier.
link |
01:48:16.860
Others will maintain lower blood glucose
link |
01:48:19.140
and will allow you to be more controlled
link |
01:48:21.940
in the foods that you pursue.
link |
01:48:23.980
Those are all individual considerations
link |
01:48:25.820
that are deserving of their own entire episode.
link |
01:48:28.180
But I do want to point out that the advantage
link |
01:48:31.100
of time-restricted feeding is that it involves
link |
01:48:33.660
a lot of the decision-making in the brain,
link |
01:48:35.700
the so-called go, no-go circuitries of our basal ganglia,
link |
01:48:39.340
if you want to know those areas that control them.
link |
01:48:41.360
Anytime we have to restrict a behavior,
link |
01:48:43.660
that's called a no-go.
link |
01:48:45.540
Anytime we engage in a behavior, that's a go.
link |
01:48:48.320
No-go behaviors require a lot of what's called
link |
01:48:50.800
top-down control, and it's very metabolically demanding.
link |
01:48:53.860
And so time-restricted feeding allows you to depart
link |
01:48:56.780
from the whole no-go, go negotiation
link |
01:48:59.380
that you have to undergo when you have to restrict portions.
link |
01:49:03.580
And so I think this is a reason why many people
link |
01:49:05.240
have gravitated towards time-restricted feeding
link |
01:49:07.620
and why for people that don't want to have to think
link |
01:49:10.060
about all that, it's just very straightforward.
link |
01:49:12.960
One of the more hot button issues out there
link |
01:49:15.140
is whether or not given equal amounts of caloric intake
link |
01:49:19.380
and equal amounts of activity
link |
01:49:23.020
and equal amounts of nutrients, et cetera,
link |
01:49:25.460
whether or not restricting food to a particular window
link |
01:49:28.980
biases more weight loss toward fat loss
link |
01:49:32.580
versus loss of other tissues.
link |
01:49:34.180
Because of course, when we lose weight,
link |
01:49:35.300
we can lose that from any number of different
link |
01:49:37.340
storage sites within the body, muscle, water,
link |
01:49:41.260
glycogen, or fat.
link |
01:49:44.700
Now, this is such a hot button issue
link |
01:49:47.060
that I almost don't want to get into it,
link |
01:49:48.140
but I'm going to get into it anyway,
link |
01:49:49.360
because there are data that are very interesting.
link |
01:49:53.120
This is covered in the review that I mentioned earlier
link |
01:49:56.540
that describes how if people follow
link |
01:50:00.180
a time-restricted feeding schedule for long periods of time,
link |
01:50:03.780
so 60 days or longer, there are some metabolic changes
link |
01:50:07.500
in the way that people metabolize energy
link |
01:50:10.840
that do seem to shift the system toward more fat loss
link |
01:50:14.620
relative to burning of other tissues
link |
01:50:17.140
when in a state of caloric restriction.
link |
01:50:19.120
And I want to say when in a state of caloric restriction,
link |
01:50:21.640
because there's really no way to cheat the system.
link |
01:50:23.940
There's no way that you can ingest far more calories
link |
01:50:26.200
than you burn or excrete.
link |
01:50:28.080
When I say excrete, you know, I certainly don't suggest this,
link |
01:50:31.380
but there, you know, bulimics and other people
link |
01:50:34.100
that have eating disorders will use laxatives
link |
01:50:35.900
as a way to eliminate food quickly from their system
link |
01:50:38.100
so it can't be converted into fat or other forms of energy.
link |
01:50:41.700
That's a very, in that case, it's a pathological situation,
link |
01:50:45.480
but in general, calories in versus calories out,
link |
01:50:48.020
as I mentioned earlier, is this kind of foundational element
link |
01:50:50.700
but in states of caloric restriction,
link |
01:50:53.260
meaning sub-maintenance intake,
link |
01:50:55.340
time restricted feeding does seem to bias
link |
01:50:59.940
more of the energy burned to compensate
link |
01:51:03.700
for that deficit from fat.
link |
01:51:05.800
And the way it accomplishes it is very interesting.
link |
01:51:08.560
It turns out that it drives more fat loss
link |
01:51:11.460
by way of increasing a hepatic lipase.
link |
01:51:14.180
This is something called LIPC,
link |
01:51:15.780
hepatic means of the liver and lipase,
link |
01:51:18.300
which anytime you hear ASE is means it's an enzyme.
link |
01:51:22.300
So it seems to increase hepatic lipase.
link |
01:51:24.820
So it increases the enzyme that metabolizes fat
link |
01:51:28.300
for lipolysis and energy production
link |
01:51:30.260
and reduces something called CIDEC, C-I-D-E-C,
link |
01:51:34.380
which is a lipid droplet associated and lipolysis inhibitor.
link |
01:51:38.620
Now that's a mouthful, no pun intended,
link |
01:51:41.260
but what CIDEC really is,
link |
01:51:44.440
this lipid droplet associated molecule
link |
01:51:47.420
is it can inhibit lipolysis.
link |
01:51:50.380
So extended periods of time restricted feeding,
link |
01:51:54.340
meaning eight hour feeding window or 10 hour feeding window
link |
01:51:57.940
that's obeyed for several months or more
link |
01:52:01.380
seems to allow the system to shift toward burning more fat
link |
01:52:07.140
or rather using a higher percentage of fat
link |
01:52:10.820
when in a caloric deficit.
link |
01:52:13.140
Now, I doubt that this is going to resolve
link |
01:52:15.580
the truly barbed wire,
link |
01:52:17.500
almost hairball ridiculous online debates
link |
01:52:19.960
about whether or not time restricted feeding
link |
01:52:21.780
is better than another feeding schedule.
link |
01:52:23.340
Look, I don't think any particular feeding schedule
link |
01:52:25.460
is holy.
link |
01:52:26.460
If you are sub caloric,
link |
01:52:27.860
meaning fewer calories burned than calories ingested,
link |
01:52:30.140
you're going to lose weight.
link |
01:52:31.560
But the data seemed to point to the fact
link |
01:52:33.460
that if you do time restricted feeding
link |
01:52:35.260
for a fairly long duration of time,
link |
01:52:37.620
and you maintain that,
link |
01:52:39.020
that you are increasing these lipases
link |
01:52:41.060
that increase lipolysis, energy use from fat,
link |
01:52:45.820
and you're decreasing the lipid droplet
link |
01:52:48.160
associated lipolysis inhibitors.
link |
01:52:50.300
So it's both a,
link |
01:52:51.780
you're removing the break and you're pressing
link |
01:52:53.700
on the accelerator of fat loss.
link |
01:52:55.820
I think that this logically points to a case
link |
01:52:59.860
in which using time restricted feeding
link |
01:53:02.820
with a sub caloric intake seems to be,
link |
01:53:05.860
at least to my mind,
link |
01:53:07.220
the most scientifically supported way
link |
01:53:09.300
to ensure that a significant portion of the weight
link |
01:53:12.980
that one loses is from body fat stores.
link |
01:53:15.520
Any discussion about fasting would be incomplete
link |
01:53:18.700
without a discussion about what does
link |
01:53:20.580
and does not break a fast.
link |
01:53:23.100
However, there is no black and white answer
link |
01:53:26.060
to that question.
link |
01:53:27.040
And you should immediately understand why.
link |
01:53:29.820
It's because eating and not eating
link |
01:53:33.820
are not equivalent to fed and fasted.
link |
01:53:36.660
It depends on when you ate,
link |
01:53:38.900
how much you ate and where you are in your circadian cycle.
link |
01:53:44.760
We can actually arrive at a simple answer
link |
01:53:46.780
to whether or not something breaks the fast or not.
link |
01:53:49.140
Now, the technical way to go about this,
link |
01:53:50.560
would be to wear a continuous glucose monitor
link |
01:53:53.280
and to ingest little bits of food of different kinds
link |
01:53:56.220
or large amounts of food of different kinds
link |
01:53:58.260
and measure blood glucose,
link |
01:53:59.820
because ultimately blood glucose is the readout
link |
01:54:02.860
of whether or not your system is in a fed or fasted state.
link |
01:54:05.380
There are other parameters too, of course,
link |
01:54:06.940
but that's the dominant one.
link |
01:54:10.760
In so far as the scientific literature says,
link |
01:54:14.580
drinking water will not break your fast.
link |
01:54:17.560
Drinking tea will not break your fast.
link |
01:54:21.660
Drinking coffee provided it is black coffee
link |
01:54:23.940
will not break your fast.
link |
01:54:26.920
Ingesting caffeine in pill form will not break your fast.
link |
01:54:30.840
There are other things that won't break your fast.
link |
01:54:33.200
For instance, eating one peanut
link |
01:54:35.300
when deep in a fasted state will not break your fast.
link |
01:54:38.880
Eating a whole handful of peanuts
link |
01:54:40.300
might not even break your fast
link |
01:54:41.780
if you are in a very low glucose state.
link |
01:54:44.740
However, if you just finished a meal
link |
01:54:46.340
that included carbohydrates
link |
01:54:47.960
or it was a very large meal of any kind an hour ago,
link |
01:54:52.000
yes, indeed, eating one peanut could break your fast.
link |
01:54:55.800
So it's all contextual.
link |
01:54:57.840
That's what's really important to understand.
link |
01:54:59.720
Unless you're going to wear a continuous glucose monitor
link |
01:55:02.780
and unless you're going to wear a continuous glucose monitor
link |
01:55:05.860
and set an absolute numerical threshold
link |
01:55:08.900
for what it is to break your fast,
link |
01:55:11.340
I think there are some simple rules that we can follow.
link |
01:55:14.040
First of all, anything that involves sugar,
link |
01:55:19.040
in particular, simple sugars
link |
01:55:20.500
can potentially break your fast.
link |
01:55:21.820
And there's actually a study on this
link |
01:55:23.380
which shows that if people ingest even one,
link |
01:55:27.720
one gram of sugar post dinner,
link |
01:55:31.260
if they had a full meal for dinner,
link |
01:55:33.400
that can actually disrupt the expression
link |
01:55:36.140
of some of the circadian genes related to fasting
link |
01:55:39.660
and to sleep and sleep-related fasting.
link |
01:55:41.920
Now that's pretty extreme.
link |
01:55:43.180
It's almost kind of scary to think about,
link |
01:55:45.480
but that's how sensitive our system is
link |
01:55:47.540
if we already have somewhat elevated blood glucose
link |
01:55:50.700
from a meal that we ate an hour or so ago.
link |
01:55:53.420
Whereas if we have run for an hour
link |
01:55:57.020
or trained hard high-intensity training
link |
01:56:00.000
and we haven't quite reached the beginning
link |
01:56:02.060
of our so-called feeding window,
link |
01:56:04.400
will eating a small amount of food take us out of that fast?
link |
01:56:09.860
Well, depends on what the food is.
link |
01:56:11.880
If it's mostly fat, probably not.
link |
01:56:14.660
A number of people out there nowadays
link |
01:56:15.980
talk about so-called fat fasting.
link |
01:56:17.740
Fat fasting is a way to kind of wriggle past
link |
01:56:20.960
the stringency of either eating or not eating
link |
01:56:25.260
as a black and white rule for feeding window
link |
01:56:28.240
versus non-feeding window.
link |
01:56:29.640
So some people will ingest medium chain triglycerides,
link |
01:56:33.380
so-called MCTs, or people will ingest fats only
link |
01:56:36.800
until their official feeding window begins.
link |
01:56:38.940
So these are sort of how the negotiations
link |
01:56:40.860
that people carry out tend to go.
link |
01:56:42.860
But fat, of course, won't increase blood glucose
link |
01:56:45.720
and insulin as much as carbohydrates will.
link |
01:56:47.880
Protein will have sort of an intermediate effect.
link |
01:56:50.900
And as I mentioned earlier,
link |
01:56:52.060
ingesting carbohydrates with some fat
link |
01:56:54.300
will tend to blunt the rise in glucose
link |
01:56:57.060
and will extend the duration over which glucose is released.
link |
01:57:00.380
So we really can't say food X
link |
01:57:04.460
or beverage X breaks a fast.
link |
01:57:07.380
However, at the extremes, we can say that.
link |
01:57:09.900
For instance, if you drink a can of soda pop,
link |
01:57:13.700
unless you just ran an ultra marathon,
link |
01:57:16.040
you're breaking your fast, okay?
link |
01:57:17.780
Eat a piece of pizza, you're breaking your fast.
link |
01:57:19.960
If you eat purely fats, maybe, probably not.
link |
01:57:23.620
If you've been fasting for five hours or more,
link |
01:57:27.020
strictly fasting for five hours or more.
link |
01:57:29.100
So you can start to see where there's a lot of wiggle room
link |
01:57:32.020
and it's very contextual.
link |
01:57:33.500
And this is why any posts that you see
link |
01:57:36.120
or any information that you see that something does
link |
01:57:38.180
or does not break your fast that doesn't place it
link |
01:57:40.100
in the context of when the last time you ate
link |
01:57:43.500
and what you ate and your activity
link |
01:57:46.700
and your time within the circadian clock schedule
link |
01:57:49.180
of 24 hours, it's a sort of meaningless discussion.
link |
01:57:52.520
So in general, I think what's really useful
link |
01:57:54.740
if you're not going to wear a continuous glucose monitor
link |
01:57:57.540
is to try and be fairly strict
link |
01:57:59.760
about when you initiate your feeding window
link |
01:58:01.740
and when you stop your feeding window.
link |
01:58:03.420
And as time evolves and you establish a more regular routine
link |
01:58:06.820
of eating certain kinds of foods and not others
link |
01:58:08.600
that are right for you,
link |
01:58:09.440
because as I've emphasized before on this podcast
link |
01:58:11.660
and I will continue to emphasize,
link |
01:58:13.180
keto works great for some people,
link |
01:58:15.140
vegetarian keto works great for some people,
link |
01:58:17.260
carnivore diet works great for other people.
link |
01:58:20.220
Some people are omnivores, some people are carnivores,
link |
01:58:22.660
some people are vegan.
link |
01:58:24.460
All of that is great and fine by me.
link |
01:58:26.280
Everyone has to establish what's right for them.
link |
01:58:27.980
Today, we've really bypassed the discussion
link |
01:58:31.260
about foods of a particular origin or type,
link |
01:58:34.700
animal-based or plant-based,
link |
01:58:36.260
but all the same rules apply within this thing
link |
01:58:39.620
that we're call intermittent fasting
link |
01:58:41.500
or time-restricted feeding.
link |
01:58:42.740
So what breaks a fast will depend and what you want to eat
link |
01:58:46.540
or what you are willing to eat,
link |
01:58:48.220
that's a totally separate manner from when you eat.
link |
01:58:51.320
But as we've established, when you eat is vitally important.
link |
01:58:55.220
Some of you are probably wondering whether or not
link |
01:58:57.820
artificial sweeteners or non-artificial plant-based
link |
01:59:01.460
sweeteners like stevia break a fast.
link |
01:59:04.400
This will vary somewhat.
link |
01:59:06.880
And I have to say the data on this are somewhat mixed.
link |
01:59:10.700
There is evidence that when people ingest
link |
01:59:14.320
artificial sweeteners,
link |
01:59:15.520
that it can create a transient increase in blood glucose
link |
01:59:19.160
followed by a transient decrease in blood glucose
link |
01:59:22.240
below baseline.
link |
01:59:23.880
This is thought to explain the increase in hunger
link |
01:59:26.280
caused by ingestion of things like aspartame and sucralose
link |
01:59:29.100
and things of that sort.
link |
01:59:30.360
There are not a lot of good studies
link |
01:59:32.420
exploring the plant-based non sugar sweeteners,
link |
01:59:36.360
things like stevia, even things like monk fruit,
link |
01:59:39.360
which is a separate category into itself.
link |
01:59:41.680
There aren't a lot of studies on this.
link |
01:59:43.040
I think most people need to establish this for themselves.
link |
01:59:45.540
The best way of course,
link |
01:59:46.380
would be to wear a continuous glucose monitor
link |
01:59:48.640
to go into a fasted state of either one hour or two hours,
link |
01:59:51.280
or maybe you've been fasting all night
link |
01:59:52.600
and then ingest stevia in whatever form you want
link |
01:59:55.600
or coffee in whatever form you want with sucralose
link |
01:59:59.000
or aspartame, et cetera,
link |
02:00:00.440
setting aside the discussion about the effects
link |
02:00:02.880
of these things on the gut microbiome,
link |
02:00:04.720
which is a different topic entirely.
link |
02:00:07.160
I think it's fair to say that in moderation,
link |
02:00:10.020
the plant-based non sugar sweeteners like stevia
link |
02:00:13.800
in particular stevia seem to have a minimal impact
link |
02:00:17.160
on overall blood glucose
link |
02:00:18.640
when considered over a fairly large time bin.
link |
02:00:21.840
Aspartame and sucralose, saccharin,
link |
02:00:24.680
I think we can say more or less the same,
link |
02:00:26.080
but as soon as you get into a discussion about those,
link |
02:00:27.940
you also have to get into a discussion
link |
02:00:29.440
about some of the evidence published in nature
link |
02:00:32.940
and other excellent journals now,
link |
02:00:35.120
pointing to the fact that when consumed in excess,
link |
02:00:37.920
not when consumed in moderation,
link |
02:00:39.960
but when consumed in excess,
link |
02:00:41.200
that those might have some detrimental effects
link |
02:00:42.900
on the gut microbiome.
link |
02:00:44.560
So do artificial sweeteners break a fast?
link |
02:00:48.240
Depends on the amount, depends on the type.
link |
02:00:50.360
And in general, I think you're probably okay,
link |
02:00:52.960
provided that you're not indulging in them too often.
link |
02:00:56.160
However, some people,
link |
02:00:57.760
just by virtue of tasting something sweet,
link |
02:01:00.400
feel a spike in their appetite that makes it harder
link |
02:01:02.780
for them to adhere to the feeding window.
link |
02:01:04.720
And so this is why you can imagine
link |
02:01:06.460
that a really well controlled study on this
link |
02:01:08.940
would be very hard to carry out.
link |
02:01:10.280
And I'm not really sure that it's worth our tax dollars
link |
02:01:12.580
to actually design and carry out a study like that,
link |
02:01:15.500
because there would be so much individual variation
link |
02:01:18.140
in terms of discipline in adhering to the feeding window,
link |
02:01:21.360
whether or not people experience increases
link |
02:01:23.200
and drops in blood glucose, how that impacts them,
link |
02:01:25.280
whether or not they're exercising,
link |
02:01:26.340
it just becomes an infinite variable space, as we say,
link |
02:01:29.960
in experimental science.
link |
02:01:31.320
So you really have to determine that for you.
link |
02:01:33.040
But I don't think that we can fairly say
link |
02:01:36.480
that artificial sweeteners break a fast.
link |
02:01:38.640
I think that would be incorrect to say.
link |
02:01:40.560
Earlier, we were talking about glucose disposal agents,
link |
02:01:43.480
both behavioral and compound based,
link |
02:01:46.600
things like metformin and berberine.
link |
02:01:48.160
And in fact, cinnamon is even a mild glucose disposal agent.
link |
02:01:52.080
It can actually reduce blood glucose.
link |
02:01:54.320
Lemon and lime juice, believe it or not,
link |
02:01:56.600
can lower blood glucose.
link |
02:01:58.480
You may have experienced this before
link |
02:01:59.800
of eating something very, very sweet
link |
02:02:01.440
and almost feeling kind of overwhelmed
link |
02:02:03.000
and kind of poisoned by how sweet it is,
link |
02:02:04.800
especially if you're not accustomed
link |
02:02:06.440
to eating a lot of sugary things.
link |
02:02:09.040
One quick remedy for that is actually a half lime
link |
02:02:12.240
or a half lemon squeezed into juice and drinking that
link |
02:02:15.080
just by virtue of the taste and by virtue of the fact
link |
02:02:19.000
that it will reduce blood glucose,
link |
02:02:20.920
you'll notice that that effect
link |
02:02:22.220
almost immediately disappears.
link |
02:02:24.100
That's not magic.
link |
02:02:25.200
That's the effects of acidity on blood glucose levels.
link |
02:02:28.900
So there are a number of things
link |
02:02:29.840
that can adjust blood glucose.
link |
02:02:32.400
They're not necessarily disposal agents.
link |
02:02:34.040
They're not sweeping it out of the bloodstream
link |
02:02:36.040
in the same way that berberine or metformin would,
link |
02:02:38.120
or that high intensity exercise
link |
02:02:39.920
at the appropriate times of day would.
link |
02:02:41.640
But there is one particular thing that one can ingest
link |
02:02:45.580
that can help manage psychologically and performance wise
link |
02:02:50.580
through the fasting portion of the intermittent fasting
link |
02:02:55.060
and get you to your feeding window.
link |
02:02:57.220
And that's salt.
link |
02:02:59.140
I've talked a little bit about this on the podcast before,
link |
02:03:01.460
but because neurons use salt, sodium and potassium
link |
02:03:06.380
and magnesium, the so-called electrolytes
link |
02:03:08.520
in order to perform their magic
link |
02:03:10.500
of chemical and electrical signaling,
link |
02:03:12.140
everything you do depends on chemical
link |
02:03:13.560
and electrical signaling and all that chemical
link |
02:03:15.480
and electrical signaling requires electrolytes
link |
02:03:18.680
in some form or another.
link |
02:03:19.820
Neurons run on the passage of ions like sodium
link |
02:03:24.420
in and out of their cell membranes,
link |
02:03:27.820
or I should say across their cell membranes to be accurate.
link |
02:03:31.240
Many people find that the kind of lightheadedness,
link |
02:03:34.020
the shakiness that's accustomed
link |
02:03:36.420
with having slightly low blood sugar can be offset
link |
02:03:40.540
by taking a half teaspoon or so of sea salt,
link |
02:03:44.620
or even just a tiny pinch of salt
link |
02:03:46.300
and putting into some water and drinking it.
link |
02:03:50.220
Some people find because of the glucose lowering effects
link |
02:03:54.300
of acidity that if they're feeling kind of shaky
link |
02:03:56.420
and not well, and they put some lemon juice into water
link |
02:03:59.140
and drink that it drops their blood glucose further.
link |
02:04:01.880
So there's a common practice nowadays
link |
02:04:04.340
that's discussed on the internet of waking up,
link |
02:04:05.980
drinking some water with some lime or lemon juice in it
link |
02:04:08.660
with a little pinch of salt.
link |
02:04:09.960
I think that little pinch of salt is a good idea.
link |
02:04:12.100
What is it doing?
link |
02:04:12.940
How is it offsetting all this?
link |
02:04:14.120
Well, saltwater actually has a mild effect
link |
02:04:18.040
as a glucose disposal agent,
link |
02:04:20.020
but it has a stabilizing effect on blood volume.
link |
02:04:23.420
And so because sodium brings with it water
link |
02:04:26.800
and the so-called osmolarity of your blood and your body
link |
02:04:30.660
depends on the salt levels in your blood
link |
02:04:34.220
and brain and body.
link |
02:04:35.860
Many people find that if they're feeling shaky,
link |
02:04:38.040
they're feeling lightheaded, they can't concentrate.
link |
02:04:39.780
They think they need sugar or food,
link |
02:04:41.400
but what will actually remedy that is some salt.
link |
02:04:44.540
And I know a number of people
link |
02:04:45.700
that have incorporated this practice
link |
02:04:47.060
and have written to me and saying, oh, you know,
link |
02:04:48.560
if I just take a little bit of salt and some water,
link |
02:04:50.780
they may or may not include the lemon or lime juice.
link |
02:04:52.500
They immediately feel better
link |
02:04:54.020
and find that it's actually quite straightforward
link |
02:04:56.060
to get out to that,
link |
02:04:58.060
to wait until the feeding window kicks in.
link |
02:05:00.660
This is especially true for people that are using caffeine
link |
02:05:03.940
because when you ingest caffeine,
link |
02:05:05.180
you actually excrete a lot of water,
link |
02:05:07.100
has a diuretic effect.
link |
02:05:08.300
And with that water goes salt.
link |
02:05:10.160
So it actually causes you to excrete sodium.
link |
02:05:12.580
Now, the role of sodium in blood pressure
link |
02:05:15.580
and hypertension is, you know, quite controversial.
link |
02:05:18.780
Science Magazine,
link |
02:05:19.640
one of the premier scientific journals out there
link |
02:05:23.460
had a special issue all about salt some years ago,
link |
02:05:26.040
talking about the research around hypertension.
link |
02:05:28.580
Indeed people with chronic hypertension
link |
02:05:30.540
or high blood pressure,
link |
02:05:31.520
or very high blood pressure in particular,
link |
02:05:33.160
should be wary of ingesting too much sodium.
link |
02:05:35.500
But for most people,
link |
02:05:37.440
ingesting sodium provided they drink enough water
link |
02:05:40.520
and they don't have chronic hypertension
link |
02:05:42.400
or high blood pressure is actually beneficial.
link |
02:05:45.840
That doesn't mean you should be drinking seawater,
link |
02:05:47.220
doesn't mean you should be overindulging in salt,
link |
02:05:50.280
but many people find that they can manage
link |
02:05:53.100
their mental and physical state
link |
02:05:54.480
and even feel really terrific, real clarity of mind,
link |
02:05:57.980
and really enjoy their fast
link |
02:06:00.020
when they're ingesting sufficient salt.
link |
02:06:01.640
And all it requires really is a small pinch of salt,
link |
02:06:03.660
ideally Himalayan or sea salt,
link |
02:06:05.000
if you want to get fancy about it,
link |
02:06:06.140
but table salt would be fine.
link |
02:06:08.040
And just drinking that in some water,
link |
02:06:11.120
maybe with lemon or lime juice
link |
02:06:12.320
to offset the taste a little bit,
link |
02:06:14.520
can really stabilize one's jitters
link |
02:06:17.500
and can stabilize the mind.
link |
02:06:19.120
And you might also notice can offset that churning
link |
02:06:23.720
and yearning and appetite
link |
02:06:25.560
where you can't imagine going another five minutes
link |
02:06:27.640
before eating something,
link |
02:06:28.560
suddenly you feel okay.
link |
02:06:29.480
And that has to do with a lot of the effects of blood volume
link |
02:06:32.400
caused by ingesting salt in the appropriate amounts.
link |
02:06:35.360
In other words, sometimes you think you need food,
link |
02:06:38.160
but what you really need is salt
link |
02:06:39.600
and salt can make you feel better immediately.
link |
02:06:41.920
I'd like to mention two excellent zero cost resources.
link |
02:06:45.260
If you're going to explore time restricted feeding,
link |
02:06:47.640
or maybe if you already are doing time restricted feeding,
link |
02:06:51.680
I have no affiliation to either of these.
link |
02:06:53.800
The first is the website that I mentioned before,
link |
02:06:55.880
My Circadian Clock,
link |
02:06:56.960
which is the website hosted by Sachin Panda and colleagues.
link |
02:07:00.400
There are a lot of resources there
link |
02:07:01.860
where you can log your food intake,
link |
02:07:03.460
get information about time restricted feeding,
link |
02:07:05.260
all the science, the ongoing studies, et cetera.
link |
02:07:08.260
The other is the so-called zero app
link |
02:07:10.940
that makes it very easy to mark
link |
02:07:16.280
when you're beginning your feeding window
link |
02:07:18.080
and when you're ending your feeding window.
link |
02:07:19.440
And in so doing,
link |
02:07:20.560
marking when you are beginning your fast
link |
02:07:22.360
and ending your fast,
link |
02:07:23.360
or at least initiating the beginning of the unfed state,
link |
02:07:27.580
as we could more accurately call it.
link |
02:07:29.560
It's a terrific app.
link |
02:07:30.580
I've used it from time to time.
link |
02:07:31.960
I don't tend to use it in an ongoing basis
link |
02:07:34.900
because I'm just sort of used to eating
link |
02:07:36.560
at a particular time of day now.
link |
02:07:38.640
But anytime I've shifted that window,
link |
02:07:41.240
for instance, a few weeks ago,
link |
02:07:42.880
I started moving that protein intake
link |
02:07:44.660
and my entire feeding window earlier in the day.
link |
02:07:47.160
And because that takes some attention on my part,
link |
02:07:49.960
because I'm not used to doing that,
link |
02:07:51.640
I've been using the zero app and I like it quite a lot.
link |
02:07:54.080
It logs your progress and it gives you averages
link |
02:07:56.080
and you can see how many other people are fasting.
link |
02:07:57.860
Again, totally zero cost.
link |
02:07:59.380
I actually don't know who owns that app,
link |
02:08:01.120
but I think they've done an excellent job.
link |
02:08:03.120
The interface is really terrific.
link |
02:08:04.600
And as far as I know, it's available for Apple and Android,
link |
02:08:07.360
but it's at least available for Apple phones,
link |
02:08:09.320
which is the type of phone I happen to have.
link |
02:08:11.480
So check those out.
link |
02:08:13.120
My circadian clock, you just put that into Google,
link |
02:08:15.480
you'll find it.
link |
02:08:16.320
And the zero app, both excellent zero cost resources.
link |
02:08:20.520
In a moment, I'd like to review the parameters
link |
02:08:22.880
of a ideal feeding schedule for you
link |
02:08:26.900
and give you the variables that you can plug in
link |
02:08:29.020
to your lifestyle and your preferences.
link |
02:08:31.540
There are a couple of things that I would place
link |
02:08:33.020
into the category of frequently asked,
link |
02:08:36.220
somewhat odd, but still worthy of discussion.
link |
02:08:40.100
For instance, people have asked,
link |
02:08:42.600
will brushing your teeth with toothpaste break your fast?
link |
02:08:45.640
I think unless you're swallowing the toothpaste, no.
link |
02:08:49.540
Now, if you really want to run out
link |
02:08:50.820
and get a continuous glucose monitor and brush your teeth,
link |
02:08:53.020
then you can evaluate that.
link |
02:08:54.240
But no, people have asked,
link |
02:08:57.200
will a half glass of wine after dinner,
link |
02:08:59.620
a couple hours after dinner, break your fast?
link |
02:09:01.640
Absolutely, it absolutely will.
link |
02:09:03.700
And it's been demonstrated to do that
link |
02:09:05.920
based on the one gram of sugar,
link |
02:09:08.640
kind of eerie or scary effect that I talked about before.
link |
02:09:11.800
Scary and eerie because it just seems like one gram of sugar.
link |
02:09:15.120
How could it do that?
link |
02:09:15.960
But these are metabolic processes
link |
02:09:18.160
and they are very sensitive post meal.
link |
02:09:21.780
A few months back,
link |
02:09:22.800
I did an experiment wearing a continuous glucose monitor.
link |
02:09:26.460
And I got a surprise when I discovered
link |
02:09:29.240
that going into a sauna increases my blood glucose
link |
02:09:32.460
quite a bit, it actually spikes it as high as a meal.
link |
02:09:35.480
And then it tends to drop back down to baseline
link |
02:09:37.840
or even slightly below baseline afterwards.
link |
02:09:40.640
When I talk to people about this, somebody said,
link |
02:09:43.820
oh, it's got to be that the continuous glucose monitor
link |
02:09:46.780
was getting disrupted by the heat in the sauna.
link |
02:09:48.840
That's actually not the case.
link |
02:09:50.720
Turns out that when you go in a sauna,
link |
02:09:54.020
because you dehydrate, you're losing water.
link |
02:09:57.660
I wasn't drinking water and you're dropping a lot of water.
link |
02:10:00.320
The concentration of sugar in your blood actually goes up.
link |
02:10:03.520
And I actually put these data out
link |
02:10:06.160
in a social media post on Twitter
link |
02:10:08.460
and people were kind of shocked to see
link |
02:10:10.440
how much a sauna can spike your blood glucose.
link |
02:10:13.320
Now I do practice time restricted feeding,
link |
02:10:15.760
intermittent fasting.
link |
02:10:16.600
I'm not super strict about it.
link |
02:10:17.900
I use a kind of eight to 10 hour ish window
link |
02:10:21.320
either early in the day or late in the day.
link |
02:10:23.700
I saw this effect of the sauna.
link |
02:10:25.560
Personally, the psychological and physical health effects
link |
02:10:30.460
of the sauna are valuable enough to me
link |
02:10:33.160
that I continue to use it.
link |
02:10:34.460
I just not concerned about this increase in blood glucose
link |
02:10:37.400
to the extent that I'm going to eliminate sauna.
link |
02:10:39.560
I like to use the sauna three or four times a week
link |
02:10:41.860
before sleep.
link |
02:10:43.240
So I'll use it an hour or two before sleep.
link |
02:10:44.840
And yes, indeed, it creates this big spike in blood glucose
link |
02:10:47.640
that then drops based on change
link |
02:10:49.580
in the concentration of blood sugar.
link |
02:10:51.860
I'm just not going to worry about it.
link |
02:10:53.000
Now, if you're concerned about blood glucose spikes,
link |
02:10:55.760
then you might be worried about it.
link |
02:10:57.440
But in my case, it was one of those things
link |
02:10:59.360
where it was interesting
link |
02:11:00.820
and it was worthy of discussion, I thought,
link |
02:11:03.240
because it was somewhat surprising to me,
link |
02:11:04.580
although it makes perfect sense why this would be the case.
link |
02:11:06.820
But at the end of the day, literally,
link |
02:11:09.360
it just makes sense for me to get in the sauna.
link |
02:11:11.800
Okay, so now you've heard a lot of science.
link |
02:11:13.680
You've heard a lot of examples, even a few anecdotes,
link |
02:11:17.000
and let's come up with the ideal intermittent fasting
link |
02:11:22.000
AKA time-restricted feeding schedule for you.
link |
02:11:26.480
And when I say ideal, I mean,
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what are the variables that are negotiable?
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What are the ones that are non-negotiable?
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02:11:33.320
What is ideal for you will depend on the context
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of your life and what you are willing to do consistently.
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02:11:40.160
So first of all, we established,
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based on the discussion with Sachin,
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who is truly the premier world expert in this area,
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who knows the animal and human scientific literature
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better than anybody, has written this incredible review
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02:11:56.240
and for whom I consulted,
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02:11:57.600
that you do not want to ingest food for at least,
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02:12:03.080
I want to emphasize, at least 60 minutes post waking up.
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Second, you want to avoid ingesting any food of any kind,
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even one gram of sugar.
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Remember, this is the ideal.
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02:12:17.000
One gram of sugar even would be too much.
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For the two to three hours prior to bedtime.
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He also mentioned,
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ideally you are spending eight hours in bed.
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I didn't tell you that earlier, I saved that for now,
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but ideally you are sleeping that entire eight hours,
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but simply by being in bed for that eight hours
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and avoiding food after waking for an hour
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and before bed for two to three hours,
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you're starting to build out the duration
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of this fasted period.
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02:12:46.020
Remember that the sleep related fasting
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is particularly important for the health benefits
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02:12:54.720
of time restricted feeding.
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02:12:56.800
Again, the sleep related fasting is especially important
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02:13:00.980
because of all the cellular repair processes
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that occur in the liver, in the gut, in the microbiome,
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in the brain, all over the body.
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And because of the way that that coordinates
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the expression of the clock genes
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that are then going to wick out
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and have many other positive effects on health,
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including weight and fat loss.
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02:13:20.560
But in addition to that, liver health, et cetera.
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An eight hour feeding window as a target
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seems to be the best target feeding window,
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02:13:31.880
at least by my read of the literature
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02:13:33.660
and in discussing it with such in.
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02:13:36.000
Shorter feeding windows of four to six hours
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tend to lead to overeating
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and potentially increases in weight.
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02:13:42.420
One meal per day type eating do not seem to do that,
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but those are special cases in that most people
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can't adhere to a one meal per day type schedule,
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at least not on a regular basis.
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And it's not very compatible with most social schedules.
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02:14:00.100
Although some people may be able to adhere to that
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in a straightforward way,
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but there aren't any robust studies exploring
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the advantages of one meal per day.
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02:14:09.340
So if you feel there are advantages of one meal per day
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for you, as opposed to an eight hour feeding window,
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02:14:16.020
well then by all means, use a one meal per day approach
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02:14:19.500
or use a four to six hour feeding window
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and just make sure you don't overeat in that window.
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Remember that most people tend to not adhere
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to the eight hour feeding window.
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02:14:31.620
They say eight hours,
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but they tend to eat outside of the eight hours
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a little bit on each side.
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02:14:37.100
So if your goal is a 10 hour feeding window,
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you might want to set it to nine hours or eight hours.
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If your goal is six hours,
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you might want to set it to seven or eight hours.
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02:14:47.580
And this is simply based, or I shouldn't say simply,
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this is based on thousands, if not tens of thousands
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of human subject data points
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that Sachin and colleagues have collected.
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02:15:00.740
Regular placement of the eating window
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or feeding window every 24 hours is important.
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You don't have to be absolutely rigid
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and neurotic about this,
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but you don't want it sliding around on the weekend
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so that it's starting two hours later
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and ending two hours later a couple of days a week,
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because then you start to offset
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many of the positive health effects
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that have been demonstrated for time restricted feeding.
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02:15:27.200
Remember if you eat your food
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within a certain feeding window,
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but that feeding window shifts by a couple hours,
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it is effectively like jet lagging your system.
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It is effectively like traveling a couple of time zones over
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eating there for a few days and coming back
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when in fact you're not traveling.
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02:15:48.920
And that's because of the way that food
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adjusts the circadian clock genes.
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Now you can offset some of that through the use of light.
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02:15:55.520
And I've talked extensively about how to use light
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in previous podcasts, but again,
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early morning and all day bright light exposure
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02:16:02.620
as safely as you can, ideally from sunlight,
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not through a window, et cetera,
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avoiding bright light in the middle of the night,
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extremely important for mood,
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offsetting metabolic dysfunction, et cetera.
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02:16:13.060
Not incidentally, Sachin's early work
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was he was one of the three co-discoverers
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02:16:19.920
of the cells in the eye,
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the so-called melanopsin cells
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that set the central circadian clock.
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02:16:24.760
So he was a pioneer in that field,
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which led him to be a pioneer in this field and so on.
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02:16:28.880
But when should that eight hour window
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be placed within each 24 hour cycle?
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02:16:35.180
Well, let's talk about ideal.
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02:16:36.760
Ideal, if you really want to maximize
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all the health benefits of time restricted feeding,
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02:16:46.400
you need to extend the fast around sleep on both sides.
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02:16:50.120
You would place it smack dab in the middle of the day.
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02:16:52.680
It would be a schedule in which you started eating,
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for instance, at 10 AM and you stopped eating at 6 PM,
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an absolutely dreadful schedule for anyone
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that wants to have some semblance of a normal life.
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In my opinion,
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it's not really compatible with most schedules,
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although some people might be able to do it.
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02:17:11.760
Maybe you and your family or your friends,
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you're eating a late breakfast
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and then you're having a late-ish lunch around 2 PM
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and then you have dinner at six.
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And then assuming that you go to bed around 9.30 or 10 PM,
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that is going to extract the maximum amount
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of weight related, body fat related,
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02:17:34.240
metabolic factor related aspects of time restricted feeding.
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02:17:40.160
Some people tend to fall into a category
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where they do best placing that feeding window
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02:17:44.880
later in the day and provided it doesn't run
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02:17:48.720
too close to your sleep.
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02:17:49.660
Remember you need a two or three hour buffer
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before your sleep, where you're not ingesting anything.
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02:17:53.780
That's in order to extract the benefits
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of time restricted feeding.
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02:17:57.760
Well, then starting your feeding window at 12 PM
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and ending at 8 PM plus or minus half an hour or so,
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02:18:07.120
day-to-day seems like a perfectly reasonable schedule
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02:18:09.400
for some people starting at 2 PM and ending at 10 PM
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will be that schedule.
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02:18:14.680
Of course, you have to take into consideration
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when you exercise, if you exercise.
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02:18:19.840
For instance, I like to exercise early in the day,
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if I run or if I do some moderate or light intensity
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exercise, regardless of what type of exercise it is,
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02:18:28.440
I have no trouble waiting until my feeding window kicks in
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around noon or even 2 PM.
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But if I do high intensity weight training, for instance,
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early in the day, or if I run sprints
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and I do that at 7 AM or 8 AM by 11 AM,
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02:18:42.760
I am very, very hungry and it's hard for me
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to do other things, concentrate, et cetera.
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02:18:48.460
Now I'm not neurotic about my feeding window.
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As I mentioned before,
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I kind of let it expand and contract a bit
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02:18:53.880
around the eight hour mark and feel perfectly free
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02:18:56.480
to do that too.
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02:18:57.320
We're talking here in ideals, not in necessarily practicals,
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02:19:01.800
but other people find that they're very hungry
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02:19:05.520
when they wake up early in the day.
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02:19:07.240
If you're one of these people or you're somebody
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02:19:09.020
who really is trying to emphasize hypertrophy
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02:19:13.040
or maintenance of muscle,
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02:19:14.620
then it does seem that ingesting protein early in the day
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02:19:17.740
is beneficial, that it can be more readily converted
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02:19:21.880
into muscle tissue.
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02:19:23.640
And this has been demonstrated in at least one study.
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02:19:26.480
There's another study underway
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02:19:27.720
that's exploring this further.
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02:19:29.920
For people that are really, really interested
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02:19:31.640
in hypertrophy and building muscle,
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02:19:32.980
well then time restricted feeding