back to indexHealthy Eating & Eating Disorders - Anorexia, Bulimia, Binging | Huberman Lab Podcast #36
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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 are going to talk all about
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healthy and disordered eating.
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And indeed, we are going to talk about
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clinical eating disorders,
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such as anorexia, bulimia, and binge eating disorder,
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as well as some other related eating disorders.
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However, before we get into this material,
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I want to emphasize that today's discussion
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will include what it is to have
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a healthy relationship with food.
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We're going to talk about metabolism.
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We're going to talk about how eating frequency
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and what one eats influences things like appetite
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and satiety, as well as whether or not
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we have a healthy psychological relationship to food
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and our body weight and so-called body composition,
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the ratio of muscle to fat to bone, et cetera.
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So as we march into this conversation,
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I'd like to share with you some interesting
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and what I believe are important findings
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in the realm of nutrition and human behavior.
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I know these days, many people are excited about
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or curious about so-called intermittent fasting.
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Intermittent fasting is, as the name implies,
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simply restricting one's feeding behavior,
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eating to a particular phase of the 24 hour
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or so-called circadian cycle.
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Other forms of intermittent fasting involve
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not eating for extended periods of time,
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for entire days, or some people will extend
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to two days or three days, typically,
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and hopefully they will drink water during those times,
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sometimes referred to as water fasting,
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which means that they are ingesting fluids
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and hopefully they are ingesting electrolytes
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such as salt, potassium, and magnesium as well,
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because while one can survive for some period of time
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without ingesting calories, it is extremely important
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to continue to ingest plenty of fluids and electrolytes.
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And the reason for that is that the neurons
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of your brain and body that control your movements,
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your thoughts, clarity of thinking in general, et cetera,
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is critically dependent on the presence
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of adequate levels of sodium, potassium, and magnesium,
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the electrolytes, and that's because neurons
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can only be electrically active by way of movement
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of particular ions, which include things like sodium,
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potassium, and magnesium.
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So without those, you can't think, you can't function,
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and it actually can be quite dangerous.
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So why all the excitement about intermittent fasting?
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Well, a lot of the excitement relates to work
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that was done by a former colleague of mine
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down at the Salk Institute for Biological Studies
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in San Diego named Sachin Panda.
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Sachin's lab identified some very important
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and impactful health benefits
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of restricting one's feeding window to particular times
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within the 24-hour cycle, or even to having extended fasts
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that go for a day or two days, or maybe even three days.
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What they saw was an improvement in liver enzymes,
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an improvement in insulin sensitivity,
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which is something that is good.
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It means that you can utilize the calories
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and the blood sugar that you happen to have.
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Being insulin-insensitive is not good
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and is actually a form of diabetes.
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What Sachin's lab and subsequently other labs showed
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was that restricting one's feeding window
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to anywhere from four to eight or even 12 hours
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during each 24-hour cycle was beneficial in mice.
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And some studies in humans have also shown
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that it can be beneficial for various health parameters.
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However, the excitement about intermittent fasting
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seems to be related to the foundational truth
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about metabolism and weight loss and weight maintenance
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and weight gain, which is that regardless of whether or not
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you intermittent fast or whether or not you eat small meals
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all day long, or you eat one meal in the evening
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and snack up until then, it really doesn't matter
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in the sense that the calories that you ingest
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from whatever source are going to be filtered
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through the calories that you burn by way of exercise,
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basal metabolic rate,
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which is just the calories that you happen to burn,
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just being alive and thinking and breathing
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and your heart beating, et cetera.
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And the reason why many people prefer intermittent fasting
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to other forms of, let's just call it what it is,
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diet or nutritional framework is that many people
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find it easier to not eat than to limit their portion size.
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And here I'm not talking necessarily about eating disorders,
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I'm talking about the general population.
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So I think that's one reason why there's so much excitement
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about intermittent fasting.
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Now, within the context of intermittent fasting
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on a circadian timescale once every 24 hours,
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you generally find two categories of people.
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People who prefer to not eat in the morning,
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either because they are not hungry in the morning
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or because they find it relatively straightforward
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to just drink things like coffee or water, et cetera,
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and push their feeding window out to noon or 2 p.m.
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And then they'll eat between say 1 p.m. and 8 p.m.
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It depends on the individual.
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Other groups of people find that they are very hungry
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when they wake up in the morning.
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They don't feel well if they don't eat breakfast.
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And so they prefer to eat early in the day,
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but then they limit their feeding window
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such that they cut off their food intake
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or stop ingesting any calories of any kind
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somewhere around 5 p.m. or 6 p.m., et cetera.
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So the duration of the feeding window
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has not been broken down
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into the kind of nuanced type of information
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that one would really want,
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at least not in human studies,
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saying, well, a six-hour feeding window
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or an eight-hour feeding window is ideal.
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It really is going to vary
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based on lifestyle and circumstances.
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For instance, some families really want
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to eat dinner together every night.
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So do you want to be the person
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that's sitting there watching everybody eat
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because you're fasting from 5 p.m. onward?
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That's an individual difference.
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What you can start to identify, however,
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is that people tend to fall
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into either one category or the other,
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people who prefer to skip eating in the morning
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or people that prefer to
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or manage to skip eating in the evening.
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And there has been no evidence thus far
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that one is better or worse,
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at least in terms of weight loss or overall health parameters.
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Now, you could imagine
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that some people might eat breakfast and dinner.
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And indeed, I have several, many colleagues, in fact,
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who just choose to skip lunch
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because they're busy during the day.
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They eat breakfast and dinner.
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That doesn't afford the long fast associated with sleep.
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What do I mean by that?
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Well, if you went to sleep at 11 p.m.
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and you wake up at 6 a.m.
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by extending your fast until 1 p.m. in the afternoon,
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you get quite a long period of no ingesting any calories.
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Whereas when you don't eat during the middle of the day,
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you are getting a fasting period
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that's probably anywhere from four to seven hours,
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but it's not linked to the longer fasting period
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of not eating while you are asleep
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because most all people, and I want to emphasize most,
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do not eat while they are asleep.
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But we are going to talk about an eating disorder
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that does exist where people actually eat in their sleep.
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I know it sounds pretty wild,
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but indeed that eating disorder does exist
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and has a very interesting underlying mechanism.
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So why are we talking about this?
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And in particular, why are we talking about this
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during an episode that includes a discussion
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about eating disorders?
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The reason is nobody, not the government,
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no nutritionists, no individual,
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no matter how knowledgeable they are
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about food and nutrition and food intake,
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can define the best plan for eating for any one individual.
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I'm going to repeat that.
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Nobody knows what truly healthy eating is.
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We only know the measurements we can take.
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Liver enzymes, blood lipid profiles, body weight,
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athletic performance, mental performance,
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whether or not you're cranky all day,
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whether or not you're feeling relaxed,
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nobody knows how to define these.
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And these have strong cultural and familial
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and socio societal influence.
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So if you hang out with people
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that intermittent fast all day, that will seem normal.
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If you spend time with people
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that have never heard of intermittent fasting,
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intermittent fasting is going to seem very abnormal.
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Now we are going to talk about eating disorders
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that really fall into the category
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of clinically diagnosable eating disorders
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for which there's actually serious health hazards
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and even the serious risk of death.
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We will get to that topic.
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But for the time being, I want to emphasize
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a new set of findings
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that I think many people will find interesting
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and at least will want to consider
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in light of their current nutritional plan
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or pattern of eating,
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whether or not you're intermittent fasting or not.
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And I want to cue up an important framework
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for the rest of the conversation
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on healthy and disordered eating,
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which includes an understanding of thinking,
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decision-making and what we call homeostatic processes,
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meaning regulation of things
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that are going on in our brain and body
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and reward mechanisms.
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I'm going to return to that in a moment.
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But first I want to share with you these new findings
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that were just published in the journal Cell Reports,
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a cell press journal, excellent journal.
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This was a study that was performed both in mice
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and it included a crossover study with a human population.
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The human population was women,
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but it relates to a previous study
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that was also carried out in men.
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I'm going to simplify this study.
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We will provide a link to the full study
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so you can explore it in more detail.
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And if you're really excited about the results,
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I would encourage you to explore some of the references
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within that paper as well.
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What was the study?
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The study looked at giving mice or humans two meals
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and explored whether or not putting those meals
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early in the day or late in the day
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had an impact on muscle hypertrophy,
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muscle growth and overall protein synthesis of muscle.
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So when we eat the amino acids from various foods
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are broken down and synthesized
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into different types of tissues.
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They can be utilized for energy,
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burned up for moving about and thinking, et cetera,
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or it can be synthesized,
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those amino acids can be synthesized into skeletal muscle,
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the sorts of skill to muscles
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that allow you to move your limbs.
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This study explored how protein intake,
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which included what are called branch chain amino acids
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and amino acids like leucine,
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which are important for muscle protein synthesis.
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It explored whether or not emphasizing or skewing
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the protein intake toward early day or late day
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was better in terms of muscle hypertrophy.
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And they also looked at some parameters of strength
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like grip strength.
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Now mice are nocturnal.
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So before you say, wait, mice are nocturnal,
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how did they look during the day?
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And it's completely, it doesn't apply because it's in mice.
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Of course, they knew that.
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And they looked during the mice's active phase
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of their circadian cycle, which corresponds to our day.
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And in humans, they looked at whether or not
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eating most of one's protein early in the day
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was better than if the protein intake
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and these branch chain amino acids
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were placed later in the day.
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And yes, they had the mice do resistance training.
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They did that by emphasizing overload
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to one limb of the mouse.
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And that actually generates hypertrophy.
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It's a form of resistance training in mice.
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So they don't have them weight training.
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They weren't doing curls and dips and squats
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and things of that sort.
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They were moving their own body weight,
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but they skewed that distribution of body weight
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by restricting a limb and forcing them to use one limb
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that did indeed grow in response to that.
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And then in humans, there was an exploration of grip strength
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and then with resistance training,
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that was also carried out through a peripheral study.
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Basically the takeaway from this study
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was that mice and humans can utilize amino acids
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that are ingested early in the day
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better than they can utilize amino acids
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ingested later in the day,
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in particular toward muscle hypertrophy and growth
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or maintenance of muscle,
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which for those of you that aren't interested
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in much muscle hypertrophy,
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that aren't trying to grow your muscles,
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I've talked before in the episode
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on building strength and hypertrophy,
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that maintaining muscle,
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regardless of one's athletic prowess,
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regardless of one's age is extremely important
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because loss of skeletal muscle
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is one of the major causes of injury as we age.
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It's one of the major causes, believe it or not,
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of cognitive and metabolic deficits as we age.
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So maintaining muscle is important,
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building muscle might be important to some of you,
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but what they found was ingesting protein early in the day
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and these amino acids early in the day
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led to more muscle hypertrophy
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than if the majority of amino acids and proteins
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were ingested late in the day.
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So this translates to intermittent fasting
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such that if you are interested in muscle hypertrophy,
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you might, and I want to emphasize might,
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consider making sure that you're getting
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sufficient protein intake early in the day.
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What sources of protein you use
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is going to be highly individual.
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Some of you are meat eaters,
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some of you don't eat red meat,
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some of you eat chicken and fish and eggs,
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some of you don't, some of you are vegans.
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It has been shown that the amino acid leucine
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is vital for the cell growth process,
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including muscle growth because of its relationship
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to the so-called mTOR pathway,
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mammalian target of rapamycin.
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We can talk about that more if you like in a future episode.
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This means that if you're somebody who wants to maintain
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or increase the amount of muscle mass that you have,
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ingesting a high protein meal early in the day
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ought to be beneficial for that.
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Does it mean that you should not eat protein
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in the afternoon and evening?
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No, I think a lot of people
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might've misinterpreted this study
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and I don't want that to happen.
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This is only pointing out the fact
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that ingesting sufficient quality amino acids,
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including leucine, early in the day
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can be beneficial for maintenance
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and growth of muscle tissue.
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It does not say that you should avoid protein
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Now for you intermittent fasters, this could be relevant.
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I, for instance, was somebody who for a very long time
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skipped breakfast.
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My first meal of the day would be in the early afternoon,
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mostly protein and salad, in my case, animal protein,
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because that's in alignment with my values.
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Then in the evening, I would eat pasta, vegetables, et cetera.
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I might have some protein, some small piece of fish
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or chicken or something like that,
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but I didn't really emphasize that.
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On the basis of these results, I am experimenting with,
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I want to emphasize experimenting with,
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I haven't completely tossed out my old protocol,
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but I'm experimenting with eating proteins early in the day
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And then dinner might be a light supper of some sort,
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but not so much protein later in the evening.
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Again, if you want to eat six meals a day,
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you want to eat around the clock, I'm not going to stop you.
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I'm not telling anybody what to do.
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As I mentioned earlier, nobody knows exactly how to eat
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for one's particular goals.
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But this study was really interesting
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because it really did show that we can utilize the proteins
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that are ingested early in the day better
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than we can utilize the proteins
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that are ingested later in the day.
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And of course, there will be factors that can shift that.
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For instance, if you work out very hard
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with resistance training later in the day,
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resistance training is known to increase protein synthesis.
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So it stands to reason that ingesting amino acids
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after that training would be beneficial.
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However, in the study, it did not seem to matter
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when the resistance training fell
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within the 24 hour schedule.
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The morning ingestion or early day ingestion of amino acids
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seemed to be beneficial.
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Between the hours of about 5 a.m. and 10 a.m. for humans.
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Now, just a bit of mechanism to explain why this happens.
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So why would it be that ingesting protein early in the day
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would lead to more synthesis of muscle
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than ingesting protein later in the day?
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And the reason it turns out is related
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to the circadian clock mechanism
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that is present in all cells, including muscle cells.
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So muscles have fibers.
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I think most people are aware of that,
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that your muscles are not just one big blob of tissue.
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A lot of these little fibers that contract.
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Within those fibers, however, there are cells with nuclei.
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Those nuclei contain DNA.
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DNA is transcribed into RNA.
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RNA is translated into proteins.
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The DNA of your cells, including these muscle cells,
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are under strong circadian regulation.
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Each one has a pattern of gene expression
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that is different at different times
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during the 24 hour cycle.
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This is an unescapable reality of all cells in your body,
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right from your hair cells to your brain cells
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to your retinal cells, to your toe on both feet.
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These cells make a gene called BMAL.
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BMAL, B-M-A-L, is a clock gene.
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And the expression of this clock gene
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varies across the 24 hour cycle.
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And proteins that are downstream of this BMAL gene
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influence protein synthesis.
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The circadian regulation of this BMAL gene
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turns out to be vitally important
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for this protein synthesis mechanism.
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How do we know that?
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Well, in this particular study,
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because they had a mouse that lacked BMAL,
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the gene was knocked out.
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They had a bunch of these mice.
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They were able to explore whether or not
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this early day feeding effect was present or absent
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in these mice that lack the gene BMAL.
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And indeed it was absent.
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In other words, the effect of increased protein synthesis
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early in the day was eliminated
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in the absence of the BMAL gene.
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So what this means is that when you wake up in the morning,
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assuming you're following a standard schedule
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of being asleep at night and awake during the day,
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your muscle cells are primed to incorporate amino acids
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and synthesize muscle,
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regardless of whether or not you weight train
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the night before at 8 p.m.
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where you don't weight train at all
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or you weight train afterwards or before.
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I said 5 to 10 p.m. is the sort of critical window
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for this increased protein synthesis.
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All this means is that if you are interested
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in maintaining or enhancing muscle tissue volume,
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that you might want to consider eating quality protein
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and amino acids early in the day.
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You could train first, you could train after,
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you could not train at all.
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That's a entirely different discussion.
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What is quality protein?
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Well, quality protein is going to be a protein
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that includes most of the essential amino acids
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and in particular, leucine.
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Now there's a lot of debate as to whether or not
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you can get all the essential amino acids
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from a purely plant-based diet
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or whether or not you need to ingest
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animal-based foods or not.
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The term quality protein
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has no strict scientific definition.
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Some people define quality protein as a protein
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that has a high essential amino acid to caloric ratio.
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Now, what that means is a small piece of chicken or steak
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or eggs, for instance, will have many essential amino acids
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with a low caloric content relative to say beans
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or plant-based foods that can also get you
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essential amino acids, but it requires more calories
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to access those essential amino acids.
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Now that's a debate that has many exceptions and nuances.
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And I, for one, am perfectly respectful of the folks
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that just want to ingest plant-based foods
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in order to get their high quality protein.
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I think that actually can be done.
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One has to be careful and thoughtful in their choices
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about how to do that.
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So this really isn't about animal-based
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versus non-animal-based foods.
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This is about getting quality amino acids early in the day
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from whatever foods are in alignment
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with your particular values in your particular eating plan.
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So that's a lot of information,
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but the key takeaways are every cell in your muscles
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The clock genes vary such that protein synthesis
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is greater early in the day than it is later in the day,
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such that in both mice and in humans,
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ingestion of quality proteins early in the day
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will be more so incorporated into muscle
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than the proteins that are ingested late in the day.
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And of course, there are the caveats of
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if you're training hard late in the day,
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if you're adjusting your hormone status
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through whatever mechanism, et cetera,
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protein synthesis can also be high later in the day.
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But for most people, it's going to taper off
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due to this circadian B-mal gene-related mechanism.
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Again, we will provide a link to the study.
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And the other key takeaways were that nobody knows,
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nobody can tell you what healthy feeding windows are,
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what the best feeding windows are.
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There's absolutely no information in that context.
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You talk to 10 nutritionists or academics or trainers
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or individuals about what healthy eating is,
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and you are going to get vastly different answers.
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And that's one of the reasons why I believe that
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the internet, in particular social media,
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are so filled with contradictory opinions.
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But the calories in versus calories burned formula
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is the more or less holy foundation of all things
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about nutrition, eating, and weight.
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And as we transition today into the discussion
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about eating disorders, I'd like you to keep this in mind
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because for the treatment of eating disorders,
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it doesn't matter what psychological
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or early trauma-based effects led to the eating disorder
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if the person isn't adjusting their feeding behavior
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in a way that is going to ameliorate the symptoms
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of that disorder, which is ultimately the goal.
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Before we begin, I'd like to emphasize that this podcast
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is separate from my teaching and research roles at Stanford.
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It is, however, part of my desire and effort
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to bring zero cost 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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Our first sponsor is Belcampo.
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Belcampo is a regenerative farm in Northern California
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that raises organic, grass-fed,
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and finished certified humane meats.
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I don't eat a lot of meat,
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but I eat meat about once a day.
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That means a small piece of steak or chicken, et cetera,
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and usually a salad.
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I usually do that for breakfast or for lunch.
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And then in the evening,
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I tend to follow a more or less vegetarian diet.
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I tend to eat pastas and vegetables and things of that sort.
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While I don't eat a lot of meat,
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it's important that the meat that I eat
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be of very high quality and that I am certain
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that the animals were raised and treated humanely
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up until the point of slaughter.
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Belcampo's animals graze on open pastures
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It also results in healthy, happy cows.
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I often talk about how important omega-3 fatty acids are.
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They've been shown to be important for regulating mood,
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and elsewhere in the body.
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Belcampo's meats are known to be high in omega-3s.
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Today's podcast is also brought to us by Headspace.
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Headspace is a meditation app
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that's backed by 25 published studies
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and has over 600,000 five-star reviews.
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I've been meditating for a very long time,
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although I admit I meditate on and off,
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meaning I'll go a few weeks or months,
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meditating regularly, and then I tend to stop.
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A few years ago, I got into a regular meditation practice
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because I started using Headspace's meditation app.
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The thing I really like about their meditation app
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That's the best deal offered by Headspace right now.
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So again, if you're interested, go to headspace.com
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slash special offer.
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Today's episode is also brought to us by Athletic Greens.
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Athletic Greens is a vitamin mineral probiotic drink,
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and it's one that I've been drinking since 2012.
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The reason I started drinking Athletic Greens
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and the reason I still take Athletic Greens
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is that it really helps me cover all of my nutritional bases
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with respect to vitamins and minerals and probiotics.
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And we now know that a healthy gut microbiome
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is supported by probiotics.
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I mix mine with some water and some lemon juice.
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regulating inflammation and so on.
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So go to athleticgreens.com slash Huberman
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to get the Athletic Greens, the five free travel packs,
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and the year supply of D3 and K2.
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So let's talk about eating disorders.
link |
And as we do that, I want to emphasize again,
link |
that nobody can really define what healthy eating is
link |
with a single protocol.
link |
However, there is some general agreement
link |
about what unhealthy and disordered eating is.
link |
There are clear criteria in the psychiatric
link |
and psychological communities to define things
link |
like anorexia, bulimia, binge eating disorder,
link |
all of which we will talk about.
link |
But as we have that discussion,
link |
I want to emphasize that self-diagnosis
link |
can be both a terrific, but also a very precarious thing.
link |
We talked about this a little bit
link |
in the episode about depression.
link |
There's always a temptation,
link |
as one learns about the symptomology of a given disorder,
link |
doesn't really matter what the disorder is,
link |
to ask the question, well, do I have that?
link |
Does so-and-so that I know have that?
link |
Ah, I see this sort of behavior or that pattern of thinking
link |
in that individual.
link |
It's tempting to diagnose them and or ourselves
link |
as either having or not having a particular disorder.
link |
However, diagnoses really need to be carried out
link |
by people who are trained in that particular field
link |
and that have deep expertise
link |
in recognizing the symptomology,
link |
including some of the more subtle symptomology
link |
of eating disorders.
link |
So if any of the symptoms resonate with you,
link |
by way of you thinking that you have
link |
this particular disorder or someone that you know
link |
has a disorder, I would take that seriously,
link |
but I would take that information
link |
to a qualified healthcare professional
link |
that could diagnose or rule out
link |
any of these possible disorders.
link |
I say that not to protect us, but to protect you,
link |
because information is valuable.
link |
And I do believe that knowledge of knowledge
link |
can be very valuable in navigating any topic
link |
and improving our thoughts and behaviors around that topic.
link |
But one doesn't want to,
link |
or I should say one shouldn't start to self-diagnose
link |
simply on the basis of information
link |
without running that through the filter
link |
of a qualified professional.
link |
So what is an eating disorder?
link |
Well, we have to take a step back
link |
and confess to the fact that every society, every culture,
link |
every family and every individual
link |
has a different relationship to food.
link |
Eating disorders, however, have particular criteria
link |
that allow us to define them
link |
and to think about different modes of treatment
link |
as it relates to the particular symptoms,
link |
in particular the psychological
link |
and biological symptoms of those disorders.
link |
Now that's a mouthful, no pun intended.
link |
What are the major eating disorders?
link |
Anorexia nervosa, most commonly referred to as anorexia,
link |
is perhaps the most prevalent
link |
and the most dangerous of all eating disorders.
link |
In fact, anorexia is the most dangerous
link |
psychiatric disorder of all, even more than depression.
link |
The probability of death for untreated anorexia
link |
And sadly, the prevalence of anorexia is very high.
link |
So what is anorexia and how prevalent is it?
link |
Anorexia, if you look it up online
link |
or you talk to a qualified professional,
link |
is essentially a failure to eat enough
link |
to maintain a healthy weight.
link |
You can see all sorts of very troubling symptoms
link |
of somebody who's been anorexic for some period of time.
link |
A general loss of muscle mass
link |
because they're ingesting fewer calories than they burn.
link |
Muscle is very metabolically active.
link |
They tend to lose a lot of muscle mass.
link |
They will have a low heart rate.
link |
This is the body and brain's attempt to lower energy output.
link |
They will have low blood pressure.
link |
They will sometimes have symptoms like fainting.
link |
They will have sometimes even hair growth on the face,
link |
something called lanugo,
link |
which is essentially the body's attempt to insulate the body
link |
because of loss of body heat when you're that thin.
link |
Loss of bone density, osteoporosis,
link |
loss of periods in girls and women
link |
and all sorts of disrupted gut and immune functions.
link |
So there are just tons of terrible symptoms of anorexia
link |
that really placed the anorexic into a very risky state,
link |
which is why mortality from anorexia gone untreated
link |
is extremely high.
link |
Now, one of the misconceptions about anorexia
link |
is that it stems from an overemphasis on perfectionism
link |
or that because of all the images in social media
link |
and in advertising of extremely thin and fit
link |
or muscular people,
link |
that individuals are looking at themselves
link |
and comparing themselves to those images
link |
and thinking that they don't match up
link |
in developing anorexia.
link |
That turns out to not be the case.
link |
If you look at the prevalence or the rates of anorexia
link |
in the last 10 years or 20 years,
link |
and you compare that to when anorexia was first identified,
link |
which was in the 1600s and perhaps even earlier,
link |
what you find is that rates of anorexia are not going up.
link |
So this idea that the images that we're being bombarded with
link |
are causing anorexia doesn't seem to be true.
link |
Now, that is not to say that the images
link |
that we in particular young people are being bombarded with
link |
are healthy for their psychological state of mind,
link |
but classically defined anorexia
link |
has existed as essentially the same prevalence
link |
for the last 100, 200, 300 and 400 years,
link |
which is incredible and really speaks to the likelihood
link |
that there's a strong biological contribution
link |
to what we call anorexia nervosa.
link |
Anorexia nervosa is extremely common.
link |
It's anywhere from one to 2% of women.
link |
And the typical onset is in adolescence, close to puberty,
link |
but it can show up later in life as well.
link |
In fact, the identification and diagnosis of anorexia
link |
tends to be in the early 20s,
link |
but if you look back at the history of those individuals,
link |
there were typically signs of anorexia
link |
that stem back into their early teens
link |
or maybe even before that.
link |
Now, of course, men can be anorexic as well,
link |
but anorexia nervosa does seem to occur
link |
at 10 times the rate in women and young girls
link |
than it does in men and young boys.
link |
So while there does seem to be more of a prevalence
link |
of anorexia in boys and young men these days,
link |
that's probably due to better diagnosis and detection
link |
than it is to some sort of societal shift
link |
related to imagery, et cetera.
link |
Later, we will talk about body dysmorphia
link |
and some of the images that are present in media
link |
and social media and how those are impacting
link |
other forms of eating disorders.
link |
But when you look at anorexia nervosa,
link |
this failure to maintain weight, even to healthy levels
link |
and often drops in weight that are very dangerous
link |
or even deadly, that has existed for a very long time
link |
and seems to be somewhat hardwired into the biology
link |
of individuals that suffer from it.
link |
Now, when I say hardwired, that doesn't mean
link |
that it can't be treated or cured and indeed it can.
link |
Bulimia, which is defined as binge eating or overeating,
link |
let me explain what that is.
link |
Binge eating is consuming vast amounts of calories
link |
in a short period of time.
link |
Overeating can be ingesting more calories than one needs,
link |
but over an extended period of time,
link |
both can exist, of course, but bulimia is also very common.
link |
It's more common in young girls and in women
link |
than it is in young boys and in men,
link |
but it is present in both sexes.
link |
Bulimia and rates of bulimia might be increasing.
link |
That's sort of an interesting finding.
link |
It's not quite clear whether or not it's existed
link |
in its same form for a long period of time
link |
or whether or not there are new forms that are evolving
link |
We're going to drill into bulimia and what it actually is
link |
and what it represents.
link |
But one thing I want to be clear about,
link |
just as the perfectionist mindset has been associated
link |
with anorexia, and it turns out that's not the case.
link |
It can be, but it's not always associated with anorexia.
link |
There was the idea that bulimia is associated
link |
with early trauma in childhood,
link |
in particular sexual trauma.
link |
And while that can be the case,
link |
there's no direct correlation between the two.
link |
Now, obviously psychological phenomena and trauma
link |
can have a profound impact on the way that the brain
link |
wires up and the way that people approach food
link |
and other types of behaviors.
link |
But the sort of classic idea was that all anorexics
link |
are perfectionists, they want to perform well,
link |
it's all about control and autonomy,
link |
and bulimics are kind of dysregulated and acting out
link |
against some early sexual trauma.
link |
Those stereotypes of the psychological framework
link |
of anorexics and bulimics doesn't hold up
link |
when you look at the data.
link |
Many meta analyses have been done,
link |
it just simply is not the case.
link |
And in both instances, both anorexia and bulimia,
link |
there are clear biological underpinnings
link |
to what's driving the undereating or the overeating.
link |
So we're going to talk about the biology of undereating
link |
and overeating and appropriate levels of eating.
link |
And by doing that, we will start to identify
link |
some of the mechanisms that serve as entry points
link |
for the treatment of both anorexia and bulimia.
link |
And as some of you are probably aware,
link |
anorexia and bulimia can be comorbid,
link |
they can exist with one another.
link |
There are anorexics who will binge and then purge
link |
in order to maintain that unhealthily low weight.
link |
There are bulimics who fit the psychological criteria
link |
of anorexia, and so there's a lot of overlap
link |
between those two categories.
link |
Now let's talk about the categorization for a second
link |
and why the categorization has led to now
link |
a bunch of other eating disorders
link |
as defined by the psychiatric community.
link |
One of the classic symptoms of anorexia
link |
is a loss of menstrual cycles, loss of periods.
link |
And the reason for that is when the body is undernourished,
link |
the body fat stores send signals to the brain
link |
to inform that the body is undernourished
link |
or they turn off the signals that say,
link |
look, there are enough body fat cells out here
link |
to support healthy metabolism,
link |
and therefore let's shut down ovulation.
link |
Literally signals sent from the fat and muscle to the brain
link |
and the brain, the hypothalamus and pituitary
link |
will send signals down to the ovaries
link |
or they will turn off the signals heading to the ovaries
link |
to deploy eggs, the maturation of eggs
link |
in the follicle, et cetera.
link |
So there are instances in which people have anorexia
link |
or have bulimia, but are still maintaining
link |
healthy menstrual cycles, or at least menstrual cycles.
link |
And that has led to a whole set of other categorizations
link |
of eating disorders like binge eating disorder,
link |
where there tends to be a lot of overeating,
link |
but not the purging, or categorizations of anorexia
link |
in which people are underfeeding,
link |
but they are not losing their periods.
link |
And so these have a number of different names and acronyms.
link |
Some of them include things like EDNOS.
link |
EDNOS is eating disorder, not otherwise specified.
link |
So that's a sub-categorization or OSFEDS.
link |
So OSFEDS is other specified feeding or eating disorder.
link |
So right now, if you were to look online
link |
or you're looking into the psychiatric
link |
and psychological textbooks,
link |
what you would find is that there's a huge constellation
link |
of eating disorders.
link |
Today, we're mainly going to talk about anorexia,
link |
bulimia, binge eating disorder, and body dysmorphia.
link |
You can even find eating disorders like pica,
link |
where people actually ingest things like dirt
link |
or rocks or metal because they have a genuine appetite
link |
I certainly do not recommend sampling
link |
any of those non-food items as foods.
link |
It is incredibly dangerous.
link |
People often poison themselves.
link |
They often can cause structural blockages.
link |
Some people have died from those sorts of things,
link |
but nonetheless, there are aspects of our brain and biology
link |
that when disrupted can lead to very bizarre types
link |
of eating behavior.
link |
Sometimes pica is caused by malnutrition, but not always.
link |
And so today we're going to focus
link |
on the most prevalent eating disorders,
link |
but we are going to build up toward that understanding
link |
by looking at what healthy metabolism and eating
link |
and satiety and hunger looks like.
link |
Because one, I realized that not everyone out there
link |
has an eating disorder.
link |
And two, I want people to understand this relationship
link |
between how they think,
link |
the decisions they take about what they eat,
link |
and how the body and the brain at subconscious levels
link |
are driving some of these behaviors,
link |
healthy or otherwise,
link |
because I do think that it can lead us
link |
to a better understanding of what healthy eating is
link |
for most of us, and to increase compassion
link |
and hopefully even increased improvement
link |
in treatment of eating disorders for those
link |
that are suffering from them.
link |
So what is hunger and what is satiety?
link |
Satiety, of course, being sated
link |
or feeling like we've had enough food.
link |
I want to remind people of the basic mechanisms
link |
by which the brain and body communicate.
link |
This is vitally important, not just for this discussion,
link |
but for any discussion about how we think,
link |
how we behave, how we feel.
link |
The body is communicating two types of information
link |
to the brain on a regular basis,
link |
but in particular around feeding.
link |
And those two types of information
link |
are mechanical information and chemical information.
link |
What do I mean by mechanical information?
link |
Well, if you take a deep breath and you hold your breath,
link |
what you'll find is that you can hold your breath
link |
a lot longer than if you exhale all your air
link |
and you hold your breath with lungs empty.
link |
And the reason is not because when your lungs are full,
link |
you have enough oxygen,
link |
and therefore you can hold your breath.
link |
It's because when your lungs are full,
link |
a particular class of neurons called baroreceptors
link |
send information to the brain
link |
and say there's pressure in the lungs.
link |
And that means that there's probably oxygen in here.
link |
And so the trigger to breathe is actually suppressed.
link |
When your lungs are empty,
link |
even if you have plenty of oxygen in your system,
link |
those baroreceptors send a different signal to the brain,
link |
which is there's no oxygen in here and you should breathe.
link |
And so the impulse to breathe comes earlier.
link |
Likewise, when your stomach is full,
link |
it sends signals to your brain
link |
that are purely based on this mechanical fullness.
link |
Has nothing to do with nutrients that says I'm full
link |
and therefore don't be as hungry.
link |
Don't motivate to find or ingest food.
link |
Whereas when our gut is empty,
link |
even if we have plenty of nutrients
link |
or plenty of body fat stores,
link |
we tend to focus on food a bit more.
link |
So volume and mechanical influences have a profound effect
link |
on how we think and what we consider doing or not doing.
link |
Likewise, chemical effects.
link |
When we ingest food,
link |
our so-called blood sugar or blood glucose levels go up.
link |
That information is signaled to the brain
link |
via neuronal pathways and hormonal pathways.
link |
And in particular, there are neurons within our gut
link |
that signal to areas of our brainstem
link |
that are involved in satiety in our sense of having enough
link |
that there's food in our system.
link |
So that's chemical information.
link |
So how are hunger and feeding and satiety regulated
link |
by way of mechanical and chemical signaling?
link |
You have, I have, we all have neurons in our hypothalamus
link |
that trigger eating and neurons that trigger cessation
link |
or stopping of eating.
link |
We have an accelerator on eating and we have a break.
link |
And I covered all of this in a lot of detail
link |
in the episode on feeding and metabolism and hunger.
link |
So if you want a lot more detail, see that episode.
link |
But right now, I'm just going to give you the top contour
link |
of how all that works.
link |
Your hypothalamus is an area of your forebrain,
link |
which tells you it's in the front,
link |
but it's at the base of your forebrain.
link |
So it's more or less above the roof of your mouth.
link |
The hypothalamus contains lots of different kinds of neurons,
link |
including neurons that stimulate sexual activity and desire,
link |
regulate your body temperature and control appetite
link |
and ceasing of eating and appetite.
link |
There are two types of neurons within a particular area
link |
of your hypothalamus that are relevant here.
link |
There are the so-called POMC neurons, okay?
link |
Pro opioid melanocortin neurons that tend to act
link |
as more of a break on appetite by way of another hormone
link |
called melanocyte stimulating hormone.
link |
And not so incidentally, when you're getting a lot
link |
of sunlight and you're viewing a lot of sunlight,
link |
that system is ramped up.
link |
This is why appetite is lower in the summer months
link |
than it is in the winter months.
link |
This is true in animals, and this is true in humans.
link |
And you have a class of neurons called the AGRP neurons.
link |
The AGRP neurons are the ones that stimulate feeding
link |
and they create a sort of anxiety or excitement about food.
link |
It can be positive anxiety or it can be negative anxiety.
link |
What do I mean by that?
link |
Well, have you ever seen kids heading in to get ice cream?
link |
They're absolutely excited.
link |
You see people getting ready to sit down
link |
and eat a big meal.
link |
They're excited to eat.
link |
Sometimes that's due to social factors,
link |
but they have an increase in overall levels
link |
of autonomic arousal.
link |
And depending on the context,
link |
they can feel excited or anxious,
link |
but it is a ramping up of energy.
link |
These AGRP neurons are what caused that.
link |
In fact, so much so that if you eliminate
link |
or kill these neurons, which has been done
link |
in experimental mouse models in the laboratory,
link |
but also there are humans that have lesions
link |
or neurotoxic effects on these AGRP neurons.
link |
And what you find is that they don't want to eat.
link |
They essentially become anorexic,
link |
meaning they don't want to ingest food.
link |
They have no appetite for food whatsoever.
link |
Now that's not exactly what anorexia is,
link |
but these AGRP neurons are like an accelerator
link |
on wanting to eat.
link |
Whereas if you stimulate these AGRP neurons
link |
or in humans that have say a small tumor
link |
near these AGRP neurons, they become hyperphagic.
link |
They will eat to the point of bursting.
link |
Both animals and humans that have elevated levels
link |
of these AGRP neurons are anxious.
link |
They want to eat and they will ingest food
link |
to the point where they override those mechanical
link |
and chemical signals in the body.
link |
And I know it sounds horrible and it is horrible.
link |
They will eat until the point that they burst.
link |
Now there are signals coming back from the body
link |
to inform the brain about presence
link |
of different levels of nutrients.
link |
And that generally comes from three sources.
link |
First of all, is body fat.
link |
The more body fat we have,
link |
the more we secrete a hormone called leptin,
link |
L-E-P-T-I-N, leptin from body fat.
link |
Leptin goes to the brain and suppresses appetite.
link |
This is a body to brain signaling mechanism
link |
that says, look, I've had enough.
link |
Not incidentally, leptin signaling is disrupted
link |
in people that have bulimia and obesity
link |
and certain forms of binge eating disorder.
link |
So that system is disrupted.
link |
I've had enough signal or there's enough body fat here
link |
such that you don't need to eat more.
link |
Right here, I'm sort of in the voice of the body fat
link |
trying to talk to the brain.
link |
That signal, that dialogue is mixed up or messed up.
link |
In some cases, it's absent entirely.
link |
So the body fat is signaling to the brain
link |
about how much reserve you have.
link |
It's sort of like a savings account for energy
link |
because that's what body fat is.
link |
You got lipids in there and through lipolysis,
link |
they can be metabolized.
link |
If you're interested in that process,
link |
both how to increase it and just generally how it works,
link |
you can see the episode on the science of fat loss.
link |
The body fat is doing something else really interesting
link |
that relates to anorexia.
link |
When there's sufficient levels of body fat
link |
and leptin circulating in the blood
link |
and that leptin signal gets to the brain,
link |
the hypothalamus and the pituitary gland
link |
register that signal and in a completely subconscious way,
link |
trigger the deployment of eggs in females
link |
and the production of sperm in males.
link |
So when body fat stores are very low,
link |
the reason why periods shut off
link |
or sperm production is reduced or even shut off
link |
is because there's not enough leptin
link |
getting to the hypothalamus and to the pituitary
link |
and they shut off the signals, the hormones,
link |
things like gonadotropin-releasing hormone,
link |
luteinizing hormone, follicle-stimulating hormone,
link |
all these hormones that you don't have to remember
link |
the names of if you don't want to,
link |
that travel to the ovary or to the testes
link |
and cause the ovary and testes to ovulate
link |
or to produce more sperm.
link |
So the reason why anorexics stop having periods,
link |
why they stop cycling,
link |
is because there isn't sufficient leptin
link |
in the bloodstream.
link |
Now, there have been attempts to give leptin to anorexics
link |
because leptin has been sequenced
link |
and the peptide has been synthesized
link |
and so you can inject leptin into people.
link |
There are studies where they've done that.
link |
When that happens, it does not tend
link |
to alleviate the anorexia.
link |
It does not cause people to start eating again
link |
and that actually makes sense
link |
because leptin is also a way of shutting off
link |
the hunger signals saying, it's the body fat's way
link |
of saying, hey, there's a lot of body fat here
link |
or there's sufficient body fat.
link |
There doesn't even have to be a lot,
link |
but it has in some cases been shown
link |
to rescue the menstrual cycling in some anorexics, okay?
link |
So body fat is signaling to the brain.
link |
The gut is signaling to the brain.
link |
There are neurons in your gut
link |
that are primarily responding to,
link |
meaning they fire electrical signals
link |
when there are sufficient fatty acids
link |
coming from fats you ingest,
link |
amino acids coming from proteins you ingest
link |
and sugars coming from carbohydrates and sugars,
link |
things like fructose, glucose, et cetera.
link |
Those signals are being sent from the fat
link |
and from the gut up to the brain.
link |
And therefore your body has multiple signals
link |
of directing you toward eating more or eating less.
link |
So you've got two categories of neurons,
link |
one that acts as an accelerator,
link |
the AGRP neuron saying eat, eat
link |
and gets you excited to eat.
link |
And then you have a category of neurons,
link |
the PMOC neurons that are suppressing hunger.
link |
They're acting like a break.
link |
And the body is informing the brain all the time
link |
about the status of the body
link |
and whether or not it needs more food or not.
link |
So you might ask, why is it that people who are overweight
link |
and have a lot of body fat,
link |
why they would continue to eat a lot?
link |
Well, past a certain threshold of body fat,
link |
that's when you start getting
link |
into these so-called metabolic disorders
link |
where blood glucose metabolism is disrupted,
link |
leptin signaling is disrupted.
link |
And there are all sorts of changes
link |
on both the brain side and the body end of things
link |
such that they're hungry despite the fact
link |
that the body has plenty of energy on reserve.
link |
That I think is sufficient to explain
link |
that the basics of hunger and satiety
link |
and a kind of a biological mechanism.
link |
And the important thing again to remember
link |
is that they're mechanical and chemical signals
link |
that come from fullness or absence of fullness.
link |
They come from the presence of glucose in the blood
link |
or the absence of glucose in the blood.
link |
When you haven't eaten for a long time,
link |
glucagon levels go up for instance, GLP-1 levels go up
link |
and those will drive you to seek out food and want food.
link |
And then there are these signals that are coming
link |
from body fat and from neurons in the gut.
link |
So there's a lot of convergence signal, lot of pathways.
link |
I don't offer you all those pathways to confuse you.
link |
I offer you those pathways to clarify the extent
link |
to which something as simple as eating
link |
or the decision to not eat is complicated.
link |
We've perhaps heard, or I've certainly heard that,
link |
oh, you know, it takes about 20 minutes
link |
for satiety to set in, you know,
link |
so you should eat slowly that you won't realize
link |
that you're full until about 20 minutes.
link |
That's actually not true.
link |
I don't know where that got started,
link |
but we should probably all chew our food better
link |
and eat more slowly,
link |
be more mindful of what we're eating, et cetera.
link |
So in anticipation of this episode,
link |
I consulted extensively with a colleague of mine
link |
at Stanford, who sadly for us
link |
is going off to University of Pennsylvania.
link |
So our loss is University of Pennsylvania's win.
link |
His name is Dr. Casey Halpern.
link |
He's a MD, medical doctor and neurosurgeon
link |
and a PhD who studies binge eating disorder
link |
and other types of eating disorders
link |
and how they arise in the brain.
link |
And he's developed some really pioneering treatments
link |
We'll talk more about his work
link |
a little bit later in the episode,
link |
but we got to the discussion of why a body
link |
that has sufficient energy levels
link |
would desire to eat more at all.
link |
And this is not just the case for binge eating disorder
link |
or for bulimia, but why that would be the case.
link |
You know, this is primitive biology
link |
that evolved over many tens,
link |
if not hundreds of thousands of years,
link |
you see it in mice, you see it in humans,
link |
very similar types of pathways and effects.
link |
How is it that human beings
link |
who have plenty of fat on reserve
link |
and plenty of glycogen in their liver, et cetera,
link |
in other words, plenty of energy,
link |
why they would be hungry, why they would eat at all?
link |
It seems like that just shouldn't happen.
link |
And he had a very important and I think clear
link |
and intuitive way of framing up all this stuff
link |
around eating and motivated behaviors
link |
and how they can go awry,
link |
not just in eating disorders, but in all of us.
link |
Basically what he said was from an evolutionary standpoint,
link |
it makes sense that we should eat as often as we can,
link |
as much as we can, and as fast as we can.
link |
Well, that sounds crazy.
link |
I was told to eat not too often, not too much,
link |
and to eat slowly and chew my food.
link |
But as Dr. Halperin pointed out,
link |
there are circuits in the brain to reward eating often,
link |
eating fast and cramming as much food into you as possible.
link |
Because from a purely evolutionary standpoint,
link |
food was scarce and seeking food was dangerous,
link |
whether or not it was from animal sources or not.
link |
And it's always been competitive.
link |
For those of you that grew up in families
link |
with a lot of siblings, this may resonate with you.
link |
I had just one sibling.
link |
We were competitive about certain things,
link |
but typically not competitive about food.
link |
But I had friends that had a lot of siblings.
link |
It was really interesting to see how food was served up
link |
and how it was taken in those households.
link |
It was like food would hit the table
link |
and it was just an absolute war for portions.
link |
And who got what and how much
link |
and who got a slightly bigger piece of cake, et cetera,
link |
turned out to be a frequent happening in these meals
link |
and at these birthday parties.
link |
Whereas the only children, perhaps,
link |
were used to having more food presented to them
link |
without having to compete with other members of the species.
link |
Every animal, including humans,
link |
has a hardwired circuit that we were born with
link |
that pays attention to how much food is available,
link |
how much we are getting now
link |
and how much we are likely to get in the future.
link |
And without going down the rabbit hole
link |
of arcuate nucleus biology,
link |
in two sentences, you have a hypothalamic area
link |
called the arcuate nucleus.
link |
It's a fascinating area.
link |
It's actually the area that houses these PMOC neurons
link |
and these other types of neurons
link |
that regulate hunger and satiety.
link |
And these neurons in the arcuate nucleus
link |
start getting active when we see food and think about food.
link |
They drive hunger and they drive hunger
link |
in a way that's responsive to what the food looks like,
link |
what it smells like,
link |
but also our prior history of interactions with that food.
link |
And it takes into account social context,
link |
whether or not we are going to get
link |
the whole pizza to ourselves
link |
or whether or not there are going to be others
link |
that we are going to have to compete with.
link |
So there are a lot of signals that this arcuate nucleus
link |
in your brain are paying attention to.
link |
So Dr. Halperin pointed out
link |
that you actually have an accelerator
link |
that increases your level of awareness and anxiety
link |
and sort of constricts your field of view
link |
and all your senses anytime you interact with food
link |
and is driving a primitive reflex
link |
to ingest as much food as you can, as quickly as you can,
link |
and then move on from there
link |
and presumably to do the same elsewhere.
link |
So that changed the way that I think about eating behavior
link |
and eating disorders.
link |
In fact, we could think about eating disorders
link |
like bulimia as an unmasking of that mechanism
link |
without the so-called top-down control,
link |
without the mechanisms that we use to regulate our behavior.
link |
And indeed bulimia and binge eating disorder
link |
are closely associated with impulsivity
link |
and with impulsive behaviors of other kinds,
link |
something that we also will discuss more.
link |
What's the pathway?
link |
How does this work?
link |
What is Dr. Halperin and his colleagues doing
link |
in order to try and treat things like binge eating disorder?
link |
Well, you can frame all of behavior,
link |
good decision-making and bad decision-making
link |
in a pretty simple box diagram model.
link |
And I realized that many of you are listening to this,
link |
not watching this, and there is no diagram to look at.
link |
I'll just explain it
link |
so that you can conceptualize it in your mind.
link |
We have knowledge of what we should do in one box, okay?
link |
We should eat that.
link |
We shouldn't eat that.
link |
We should wait for dinner.
link |
We shouldn't wait for dinner.
link |
And then we have what we actually do in another box, okay?
link |
Now this is true for all behaviors.
link |
We should say something or we want to say something,
link |
We shouldn't say something, but we do anyway.
link |
That's the knowledge, the kind of looping in your head.
link |
I should do my homework.
link |
I should go for a run.
link |
I shouldn't do this right now.
link |
I shouldn't be on social media.
link |
All those kinds of shoulds and shouldn'ts
link |
that are circulating in your head, that's one box.
link |
Then there's what you actually do, the behavior,
link |
whether or not you suppress the behavior,
link |
you turn off your phone and you go read a book
link |
or you go to sleep or whether or not you stay up all night
link |
or you stay up for another hour, even five minutes.
link |
In between those two boxes are two intervening forces.
link |
And those intervening forces are critically important.
link |
Those intervening forces are homeostatic processes
link |
called by some processes, same thing.
link |
Homeostatic processes that regulate the balance
link |
of different systems in your body, hot and cold,
link |
awake or asleep, dopamine and the desire to pursue things,
link |
serotonin and the desire to just relax and chill.
link |
So homeostatic processes and reward systems.
link |
And as we now move into discussion
link |
about anorexia and bulimia specifically,
link |
what you'll see is that anorexia and bulimia
link |
are not a breaking of the mindset
link |
of what one should do or shouldn't do.
link |
It's a disruption of these homeostatic and reward processes
link |
such that decision-making is completely disrupted
link |
and in many cases is not available
link |
to the anorexic or bulimic.
link |
Now, I don't want to be abstract here.
link |
What I'm saying is that the person who starves themselves
link |
to the point where they might die
link |
and in some cases sadly do die,
link |
they can know perfectly well that their behavior
link |
is leading to bad outcomes and possibly even death.
link |
And yet they are not able to intervene
link |
unless they get particular clinical help
link |
because the homeostatic processes,
link |
the signals from the body and brain that say you need food,
link |
those aren't registering in the same way
link |
that they are for other individuals.
link |
And for the bulimic or the person that suffers
link |
from binge eating disorder,
link |
they don't necessarily want to eat that food.
link |
They simply cannot help it.
link |
It's like a reflex for them
link |
because the homeostatic processes
link |
and the reward processes associated with food
link |
are such that they can't intervene
link |
between the should do X, Y, or Z,
link |
or shouldn't do X, Y, or Z
link |
and what their actual behavior is.
link |
Now, this isn't just a biological mechanistic explanation
link |
for what could have been summarized in two sentences.
link |
What this is is a roadmap
link |
of where interventions can really make a difference.
link |
So as we talk about different drug-based interventions
link |
or behavioral interventions or social interventions,
link |
I'd like you to think about whether or not
link |
those interventions are breaking into
link |
or tapping into this box of the thinking,
link |
the sort of pattern of thinking around food,
link |
whether or not it's the behavior,
link |
the actual ingestion or the restriction of food,
link |
or whether or not it's tapping into the homeostatic process,
link |
the balance of energy systems
link |
and kind of getting enough but not too much,
link |
or it's tapping into the reward system.
link |
And just as a little teaser of where we're headed,
link |
what you'll find based on the data,
link |
clinical data experiments done very carefully
link |
and very well by excellent groups,
link |
what you'll find is that anorexics
link |
have a sort of switch that's been flipped
link |
such that their decision-making
link |
is actually pretty darn good.
link |
It might even be better than yours
link |
in terms of evaluating food nutritional content,
link |
but their habits are disrupted.
link |
So they're not even consciously aware of the fact
link |
that they're making terrible and in some cases,
link |
very dangerous food choices.
link |
It turns out that habits and the way that we build
link |
and break and rebuild new habits
link |
is one of the most effective treatments for anorexia.
link |
So now let's talk about anorexia,
link |
this failure to consume enough energy
link |
such that the individual is at risk of death.
link |
And if not death, then severe metabolic disorders,
link |
lack of bone density, et cetera.
link |
As I mentioned earlier,
link |
anorexia and things that almost certainly were
link |
and are anorexia have been described as early
link |
as the 1600s and maybe even earlier.
link |
There are some records from the saints,
link |
from the 1400s of people that refuse to ingest food.
link |
Another common myth is that anorexia
link |
is only the sort of thing that you see in rich societies.
link |
These are spoiled children with so much food
link |
that they decided they're only going to focus
link |
on how slim they are, how they look in bathing suits,
link |
et cetera, not true.
link |
A careful analysis through medical epidemiology
link |
has shown that you find anorexia even in cultures
link |
and societies where food is scarce.
link |
So that really speaks to biological mechanism.
link |
Now it's hard to unveil in societies where food is scarce
link |
because a lot of people are starving and hungry,
link |
but there are individuals that choose still to avoid food
link |
and seem to have some sort of reward mechanism
link |
that rewards them or makes them feel better
link |
if they don't eat,
link |
despite the fact that their body is severely depleted
link |
So that's very interesting and points again
link |
to some disruption in some biological mechanism.
link |
Now, I want to make sure that I'm emphasizing
link |
that I'm not in favor of people,
link |
in particular young children, adolescents and teenagers,
link |
being bombarded with unrealistic imagery about bodies.
link |
But the idea that that's the cause of,
link |
or is amplifying anorexia,
link |
the data just don't seem to support that.
link |
Anorexia in its classic sense requires
link |
that there be an endocrine, meaning a hormonal disruption,
link |
menstrual abnormalities, lack of sperm production
link |
or low testosterone in males,
link |
in order to meet the classification for anorexia.
link |
But as I mentioned earlier,
link |
there are now nuanced and new classifications of anorexia
link |
that even for individuals that still menstruate
link |
or that maintain sperm production,
link |
that anorexia can still be considered
link |
a clinically diagnosable disorder.
link |
Now, typically anorexia starts in adolescence
link |
right around puberty.
link |
Let's take a look at what puberty is.
link |
Puberty at a very broad level is the most significant
link |
and dramatic developmental step anyone goes through
link |
in their lifespan.
link |
The body changes, the brain changes, perceptions change,
link |
one's own self perception changes.
link |
And most of those changes are driven by changes in circuitry
link |
within the hypothalamus.
link |
So neurons that are controlling the production
link |
of the so-called sex steroid hormones,
link |
things like testosterone, estrogen, and related hormones,
link |
prolactin, et cetera,
link |
those are all changing at very rapid rates.
link |
Anorexia tends to show up around this time
link |
in a subset of individuals who on the face of it
link |
seem to find food aversive.
link |
Now, the purely psychological theory of this
link |
is that they are fighting for autonomy.
link |
They want control.
link |
Puberty is also a time in which children and parents
link |
are in a tug of war over control.
link |
You were once a small child being told when to go to bed,
link |
sent to your room.
link |
Now you're a child that can talk back and say,
link |
I don't want to, or I refuse to.
link |
And that happens a lot in various households
link |
as I'm sure you're familiar with.
link |
Adolescence and puberty is also
link |
when girls start menstruating typically,
link |
or boys develop deeper voice,
link |
they start producing sperm, et cetera.
link |
So there are a lot of bodily changes
link |
that also drive perceptual changes
link |
and perceptual changes that drive bodily changes.
link |
And it is a dramatic shift for a young girl or boy
link |
that doesn't nourish themselves
link |
sufficiently during that period.
link |
There are a number of downstream negative effects.
link |
I'll list out some of them.
link |
These are just a subset of the effects.
link |
Hypogonadism, that's the lack of sperm production
link |
or healthy egg production.
link |
There is amenorrhea, which is the lack of menstrual cycling.
link |
Okay, so a failure to have a menstrual cycle.
link |
Reduced insulin secretion.
link |
Insulin is this hormone that's released
link |
in order to help shuttle glucose
link |
into various tissues for energy utilization.
link |
That's down because energy levels are down so much.
link |
One of the symptoms that's a little more cryptic
link |
and that has actually interesting implications
link |
for sake of the cholesterol hypothesis
link |
is that anorexics who ingest very little food
link |
often have cosmically high levels of cholesterol,
link |
including LDL, low density lipoprotein cholesterol.
link |
You say, well, how could that possibly be it?
link |
We were all told and continue to be told from many sources
link |
that ingestion of dietary cholesterol
link |
is what drives high levels of bodily cholesterol.
link |
Cholesterol is manufactured by the liver
link |
and in anorexics who consume very little food,
link |
they often have cosmically high levels of cholesterol,
link |
which is one of the kind of wrinkles
link |
in the so-called dietary cholesterol hypothesis
link |
that all of our cholesterol that we see on a blood panel
link |
is due to what we eat.
link |
But the explanation for it is that under conditions
link |
where there's not sufficient cholesterol
link |
to synthesize the sex steroid hormones,
link |
things like testosterone and estrogen,
link |
which are required in both males and females,
link |
those are made from cholesterol that the body,
link |
the liver will start generating its own cholesterol
link |
and will often overshoot the mark to a dramatic degree.
link |
So the blood lipid profiles in anorexics
link |
are often very unhealthy,
link |
despite the fact that they're eating very little food.
link |
In addition, they tend to have elevated levels
link |
of things like vasopressin,
link |
which are hormones that regulate body temperature
link |
and salt and blood volume.
link |
They tend to have low blood pressure.
link |
They can pass out.
link |
I mentioned some of the other symptoms earlier.
link |
In other words, there are a huge number
link |
of terrible things happening.
link |
Thyroid levels are down.
link |
Heart rates are down.
link |
If I'm painting a very bleak picture here,
link |
it is indeed a bleak picture.
link |
So we have to ask ourselves what can be done
link |
for the anorexic, right?
link |
Let's say it's a failure of the AGRP neurons
link |
to stimulate appetite and feeding.
link |
Let's say it's too much anxiety around food.
link |
Let's say it's because of the way that food restriction
link |
was used for reward in the household, right?
link |
I'm making this up,
link |
but you can imagine a hypothetical scenario
link |
where let's just say the mother of a particular individual
link |
is very vocal about her avoidance of food.
link |
We've seen this before, right?
link |
You've probably seen somebody who loves to cook
link |
and prepare food, but then sits down
link |
and doesn't seem to eat.
link |
And they always seem to, in air quotes, have eaten earlier.
link |
I ate while I cooked.
link |
I ate while I cooked, right?
link |
These people that you never actually see eating.
link |
We all know people like this.
link |
Are they anorexic?
link |
Possibly, we don't know.
link |
A child observes that kind of behavior.
link |
Maybe that individual is always being told
link |
how beautiful they look or how wonderful or fit they look,
link |
what incredible meals they produce.
link |
And you could imagine a purely psychosocial set of events
link |
that could lead a child to be anorexic.
link |
That doesn't seem to be the case,
link |
at least not in terms of driving classic anorexia,
link |
of really extreme deprivation of oneself from food.
link |
However, there's a strong genetic component for anorexia.
link |
So you could imagine a mild form of anorexia in a parent
link |
that is supported or exacerbated by praise
link |
so that the person feels good
link |
from the praise they're getting,
link |
that they want to be a low body weight for whatever reason,
link |
for aesthetic reasons, or for whatever reasons
link |
that happen to appeal to them.
link |
And the child has a genetic predisposition, right?
link |
We never think about genes in terms of controlling behavior,
link |
genes bias probabilities for behavior, okay?
link |
So you can have a gene for depression or for schizophrenia,
link |
but it's not deterministic in the same way
link |
that there are genes that determine your eye color
link |
or your skin color or your hair color, okay?
link |
So there's a genetic predisposition there.
link |
And that genetic predisposition could exist
link |
such that if one is rewarded enough times
link |
for a particular behavior,
link |
that behavior can start to ratchet in
link |
to our neural circuitry
link |
because behavior drives neural changes,
link |
so-called neuroplasticity.
link |
And you could imagine that that child
link |
could develop a full-blown case of anorexia.
link |
And this is why I raised at the beginning
link |
that no one really knows how to define healthy eating.
link |
And so therefore we have to rely
link |
on just identification of unhealthy behaviors.
link |
But what do we point people to in terms of
link |
what healthy replacement behaviors would be?
link |
So rather than just look at anorexics and say,
link |
they're not eating enough,
link |
and there's this huge array of terrible things
link |
that they're doing to their body and they need to eat more,
link |
we need to rescue them from themselves.
link |
Let's look under the hood.
link |
Let's look at what's known about the neural circuitry
link |
and the sorts of perceptions and behaviors
link |
of the neural circuitry is driving
link |
in order to understand what they are truly suffering from
link |
at the level of cause,
link |
not just symptoms.
link |
It's clear what they're suffering from
link |
at the level of symptoms.
link |
Symptoms are how we diagnose.
link |
I listed off a number of those things,
link |
but let's look under the hood and try and identify
link |
where one could intervene in theory
link |
in order to try and rescue the anorexic
link |
or help the anorexic rescue themselves.
link |
Because it turns out that the answer,
link |
or at least one of the answers of how to do that
link |
is not intuitive at all,
link |
at least to me was very surprising.
link |
I would be remiss if I didn't start with the obvious,
link |
which is, is there a chemical defect?
link |
Meaning, is there some disruption
link |
in one of the major chemical systems in the brain
link |
that makes anorexics anorexic?
link |
And therefore, can we replace that chemical
link |
or can we reduce some chemical
link |
and essentially eliminate anorexia?
link |
And the answer is not really sort of, maybe no.
link |
There are a lot of different chemicals
link |
in the brain and body,
link |
but there are a category of chemicals
link |
that are particularly important
link |
that if you've listened to this podcast before,
link |
even if you haven't,
link |
are going to come up again and again and again.
link |
And that is the category of chemicals
link |
in the brain and body called the neuromodulators.
link |
Neuromodulators are different than neurotransmitters
link |
in the sense that neuromodulators modulate
link |
or change the activity of brain areas and neural circuits.
link |
You can think of them as microphones
link |
that are held between particular sets of connections
link |
in the brain that make those connections in the brain
link |
more likely to be active relative to others, okay?
link |
They make them louder, so to speak.
link |
There are many neuromodulators,
link |
but the ones that are important
link |
for sake of today's discussion are the classic ones,
link |
dopamine, acetylcholine, norepinephrine, and serotonin.
link |
Let's focus on serotonin.
link |
Serotonin is a neuromodulator
link |
that tends to increase the activity
link |
of certain neural circuits,
link |
including within the hypothalamus, but also within the body,
link |
that trigger a sense of satiety of having enough,
link |
enough food, enough warmth, enough social connection,
link |
enough of any motivated goal or drive
link |
or any type of thing or behavior
link |
that one would want more of.
link |
Serotonin tends to make those circuits quiet down.
link |
Now, there are many categories of drugs
link |
that emphasize the serotonergic circuitry,
link |
meaning they cause the release of
link |
or the efficiency of serotonin in the brain and body,
link |
things like Prozac, Zoloft, Paxil, things of that variety.
link |
Those drugs have been used to some degree of success,
link |
although not much, to treat things like anorexia nervosa.
link |
That should make sense
link |
because if these drugs increase serotonin,
link |
if their general effect is to increase serotonin,
link |
it will be to lower anxiety.
link |
That sounds like a great thing.
link |
A lot of anorexics are really anxious around food.
link |
We'll talk about why.
link |
Lowering anxiety you might think
link |
would lead to ingestion of more food,
link |
but that's not often what happens.
link |
Increasing serotonin by way of some drug regimen
link |
will tend to make one less hungry
link |
because with heightened levels of serotonin
link |
in the blood and brain,
link |
there isn't the desire to go seek out the things
link |
that will raise serotonin on their own.
link |
Now, some anorexics do well
link |
or benefit from these serotonergic drugs,
link |
these drugs that increase the activity of these circuits
link |
that lead to satiety.
link |
But if you think about the major goal
link |
of treating an anorexic,
link |
it's to get them to have more hunger, more appetite.
link |
So now I want to focus on some of the work
link |
that's been done around the habits
link |
and behaviors of anorexics.
link |
Because those turned out to be ideal places
link |
The work I'm about to describe
link |
was done by Dr. Joanna Steinglass and colleagues
link |
at Columbia University in New York.
link |
And there are other groups as well.
link |
Of course, they're doing this type of work.
link |
But they did what I think are really
link |
some beautiful experiments
link |
and some beautiful explorations of potential treatments
link |
for anorexics that seem to have a quite high degree
link |
of effectiveness when they are applied correctly.
link |
First of all, there's a challenge in studying anorexia
link |
because in anorexia what you're essentially studying
link |
is the absence of a behavior.
link |
It's very hard to study the absence of a behavior
link |
as opposed to a behavior.
link |
So they did some experiments with anorexics
link |
giving them a gallery of pictures of different foods
link |
and allowing those anorexic patients to arrange those foods
link |
according to preference about what they would select,
link |
about food nutrient content, about caloric content.
link |
They essentially asked these anorexics to evaluate food.
link |
And in doing so, they were able to identify
link |
something that's very unique to anorexics
link |
at the level of their perception of food.
link |
What they found is that anorexics,
link |
rather than being anxious in the presence of food
link |
and that anxiety driving and avoidance of food,
link |
what they found is that anorexics have a hyper acuity,
link |
a hyper awareness of the fat content of foods,
link |
almost to the point of being sort of fat content savants.
link |
Now they don't necessarily know that they're doing this.
link |
They're not looking at an avocado and thinking,
link |
okay, that's X number of grams of fat rather,
link |
or looking at an apple and saying, okay, that has no fat.
link |
They start to do this more or less reflexively.
link |
Now it's a well-known symptom of anorexia,
link |
especially young anorexics that they have
link |
kind of an obsession with food, caloric contents,
link |
macronutrient ratios, meaning fat protein
link |
and carbohydrate ratios.
link |
They know caloric numbers,
link |
but then they sort of pass that information
link |
into a memory system in their brain
link |
that allows their interactions with food
link |
to be very reflexive in a way that they are actively
link |
avoiding high fat content foods, calorie rich foods,
link |
and defaulting towards very low calorie foods
link |
if they have to eat.
link |
Now, this might seem like an almost trivial result
link |
on the face of it.
link |
You think, okay, they don't like to eat.
link |
When they do eat, they eat low calorie, low fat foods, duh.
link |
But it's the way in which they are doing this subconsciously
link |
that they learn this information
link |
and then they pass it off to a reflexive habit.
link |
And that's very important because what that means
link |
is that we need to look at what processes in the brain,
link |
what chemicals drive decision-making and knowledge.
link |
And we also need to look at the areas of the brain
link |
that drive habit formation and habit execution.
link |
Because for any of you that have habits,
link |
and that means all of you,
link |
the hallmark feature of a habit is that it's reflexive.
link |
You have a mosquito bite on your leg, you scratch it.
link |
You didn't necessarily even think,
link |
oh, I'm going to scratch that.
link |
In fact, just to take a little bit of a moment of respite
link |
and talk about habits in general,
link |
there's a beautiful study that was done
link |
out of Caltech University,
link |
looking at the parking lot of where people park
link |
in the morning without designated parking spots
link |
and the trajectories that they use
link |
to walk to their offices in the morning.
link |
So they put cameras up on the roof of Caltech.
link |
This is the kind of thing that the nerdy kids at Caltech do.
link |
I think at Caltech, if you call someone a nerd is,
link |
I think it's a compliment.
link |
So my apologies to the non-nerds at Caltech.
link |
I think there's one or two of you.
link |
And for the nerdy ones of you at Caltech, you're welcome.
link |
They videotaped the behaviors of these faculty
link |
and students and staff.
link |
And what they found is that people follow trajectories
link |
from their car that are remarkably stereotyped.
link |
First of all, they tend to park always in the same spot
link |
They tend to get out of their car, of course,
link |
because they're on the driver's side
link |
or passenger side in the same place.
link |
They turn and pivot their body
link |
at approximately the same rate every day.
link |
They close the door.
link |
They put their bag on their shoulder or across their chest
link |
or however it is that they carry their briefcase
link |
or whatever it is.
link |
And they follow trajectories onto campus
link |
that are so stereotyped that you'd wonder
link |
if you just trace line after line after line,
link |
what you'd find is that every day is almost exactly the same
link |
and you do this too.
link |
You don't realize it because if you're being videotaped
link |
during this kind of behavior,
link |
it's not being released to you,
link |
but your behaviors are so stereotyped to the point
link |
where if you were to see them laid out in front of you
link |
in kind of diagrammatic format of the lines
link |
and the trajectories that you follow throughout the day,
link |
the lifting of your mug and how frequently
link |
you drink each hour, you would be amazed
link |
and probably a little bit scared
link |
by how much of a robot we all are.
link |
Now that robotic aspect of our neural circuitry is vital
link |
because it's what allows us to think about other things
link |
and do other things and drive other behaviors.
link |
But the work of Dr. Steinglass and colleagues showed
link |
that in the case of the anorexic,
link |
those habits are exactly the place
link |
where things start to go awry
link |
and that drive this very dysfunctional
link |
undereating behavior that sadly often leads to death
link |
or certainly bad medical outcomes.
link |
And it turns out that the brain areas associated
link |
with habit formation and execution
link |
are the best point of intervention.
link |
So what Dr. Steinglass and colleagues did
link |
is they took anorexics and they of course
link |
had control groups and they put them in an FMRI scanner,
link |
which are these brain scanners that allow you to evaluate
link |
which brain areas are active during particular tasks.
link |
And because when you're in one of those scanners,
link |
you're actually, I've actually been in one of these things,
link |
you're biting down on a bite bar and you're most of the time
link |
in most all of these scanners, you're immobile.
link |
So you're looking at things on a TV screen.
link |
Sometimes you can press buttons to select choices
link |
and so forth, but you can't really eat within those things.
link |
What they found was that reward-based decision-making,
link |
the drive to pursue a particular food
link |
or the drive to perform a particular task,
link |
which is a lot of what we do throughout our day,
link |
that was controlled by a brain area
link |
called the ventromedial prefrontal cortex.
link |
Let me simplify a little bit of this,
link |
but I'm going to simplify it by giving you a little detail
link |
because it's the Huberman Lab Podcast.
link |
And I believe in mechanism.
link |
Mechanism is the way that you get true understanding
link |
and that you can then be very quick
link |
and give overviews of things, but you need the mechanism.
link |
So you have reflexes and you have neural processes
link |
that include what are called duration path
link |
and outcome type processes.
link |
A duration path outcome type process,
link |
we can shorten with DPO.
link |
DPO is for all types of goal-related behaviors.
link |
if you want to get a particular grade on an exam,
link |
you want to learn something, you want to complete a workout,
link |
you want to go to the grocery store and pick some stuff up
link |
and then head home.
link |
You're going to think duration, how long do I have?
link |
Okay, do I have 45 minutes to get to the store?
link |
How long does it take to get to the store?
link |
Path, which way am I going to drive there?
link |
Which way am I going to navigate through the grocery store?
link |
Outcome, was I able to get in and get the items I need
link |
and get home in time?
link |
Okay, DPO, duration path outcome.
link |
It's a very conscious process.
link |
You tend to take into account different criteria
link |
related to what's in,
link |
what's preventing you from accomplishing what you want to do
link |
and what's helping you or assisting you.
link |
So of course, as you get to the checkout line
link |
in the grocery store,
link |
you're going to select the shortest line, for instance.
link |
So that's all DPO stuff.
link |
It requires decision-making and it's reward-based.
link |
You use these DPO type processes in the short term
link |
to pick up groceries and pick a line at the grocery store
link |
and decide which trajectory to take home.
link |
And you use them for navigating long extended processes
link |
in life, trying to get a degree or raise children
link |
or get through a particularly challenging year, et cetera.
link |
So duration path outcome and that entire process
link |
relies on your forebrain, this prefrontal cortex.
link |
The prefrontal cortex is what allows you
link |
to take information from memory,
link |
combine it with information about what's happening
link |
in the present context, and then to direct your behavior,
link |
your speech, et cetera, toward particular outcomes.
link |
And if all that sounds like a mouthful, it is,
link |
and it's very metabolically demanding.
link |
Decision-making is metabolically demanding.
link |
It takes effort, okay?
link |
Reflexes, on the other hand,
link |
don't involve the prefrontal cortex in the same way.
link |
Habits and reflexes, like once you know how to walk,
link |
you get up and you walk.
link |
You don't have to think about right foot, left foot,
link |
right foot, left foot, you just do it.
link |
That doesn't rely on prefrontal cortex.
link |
It's subconscious as it's sometimes called,
link |
but basically you don't have to use the parts of the brain
link |
that are involved in duration path
link |
and outcome type analysis, okay?
link |
So in this particular study,
link |
they examined brain activity in anorexics
link |
who are selecting different foods.
link |
And as I mentioned earlier,
link |
they have a hyperacuity or awareness
link |
of which foods contain more or less calories
link |
than other foods and what the fat content
link |
of particular foods is in particular, et cetera.
link |
They're doing all this while in a scanner.
link |
And then they look at what sorts of brain areas
link |
are active after that task is done.
link |
And what they found was really interesting.
link |
What they found was that
link |
the dorsolateral prefrontal cortex, not surprisingly,
link |
is involved in the decision-making
link |
and the evaluation of this food,
link |
which foods are going to be best to eat in this context,
link |
which foods are going to be appropriate
link |
for at least that anorexics framework
link |
about what's okay to eat and what's not okay to eat
link |
However, there are areas of the brain
link |
that were active after that decision-making process.
link |
And those are the brain areas
link |
that turn out to drive the habit
link |
of avoiding particular foods and approaching other foods.
link |
it wasn't the dorsolateral prefrontal cortex.
link |
It was an area of the brain called the dorsolateral striatum.
link |
Now, the striatum is a big area in the brain.
link |
It's involved in a lot of different things.
link |
It includes areas like the caudate and putatum.
link |
And I just want to mention, as I throw out all these names,
link |
you do not need to remember the names
link |
of these different structures.
link |
They're just there if you are interested
link |
in that level of detail.
link |
But basically you have a brain area,
link |
and anorexics have a brain area
link |
that's involved in evaluating
link |
and decision-making around food.
link |
And then another brain area
link |
that's involved in the reflexive consumption
link |
of particular foods
link |
and the reflexive avoidance of other foods.
link |
Now, if you remember way back,
link |
the beginning of the episode,
link |
I feel like it was a long time ago now,
link |
when we talked about how you have these sorts
link |
of processes in the brain,
link |
but there are always homeostatic
link |
and reward systems influencing this kind of thing.
link |
Well, in the brain of the anorexic,
link |
it turns out that the reward systems have been attached
link |
to the execution of habits
link |
in a way that is unhealthy for body weight.
link |
But at least from a purely neural circuit perspective,
link |
the reward is now given,
link |
this chemical reward in the brain is given
link |
for avoiding particular foods
link |
and only approaching these very low calorie, low fat foods.
link |
So there really does seem to be a flip in the switch
link |
in the anorexic brain that rewards them internally.
link |
They feel good when they avoid certain foods
link |
and they approach others.
link |
So it's not a deprivation based model
link |
where they are flagellating themselves
link |
or masochistic or actively avoiding food
link |
in order to punish themselves,
link |
which is interesting
link |
because a lot of psychological theories support that idea.
link |
Rather, once this transitions into a set of habits,
link |
they are actually getting a sense of reward.
link |
presumably from the release of a different neuromodulator
link |
called dopamine by approaching foods
link |
that are low fat, low calorie content.
link |
And so their whole brain circuitry is skewed
link |
toward avoiding particular things
link |
and they actually are rewarded for that
link |
and they feel good.
link |
They feel better than if they were eating
link |
in a healthy weight supporting way.
link |
Now, the dorsolateral striatum is a structure
link |
that we should think about in a little bit more depth.
link |
It's part of a set of circuits that are involved
link |
in what are called go, no-go tasks.
link |
And I don't want to go into this
link |
in a lot of detail right now
link |
because it would take us too far down the rabbit hole
link |
of neural circuitry.
link |
But basically in terms of behaviors,
link |
we both have DPO type behaviors.
link |
So decision-making reward-based behaviors
link |
and we have habits that we learn and we acquire
link |
and then we just start to execute reflexively.
link |
Things like walking, things like yawning when we're tired,
link |
things like taking a particular route
link |
through the parking lot, right?
link |
We learned that the first time we go
link |
to a given parking lot and walk into a building.
link |
But after that, we tend to follow the exact same trajectory.
link |
It becomes very automatized.
link |
It's just like we just do it without thinking.
link |
Well, the go, no-go circuitry is another aspect
link |
of our behavior where we both have to select behaviors
link |
to perform and we have to select behaviors to suppress.
link |
And the anorexic brain seems to reward suppression
link |
of one set of behaviors, ingestion of high calorie foods,
link |
and to reward focus or even hyper-focus
link |
and consumption of low fat, low calorie foods.
link |
So this homeostatic process that we learn about
link |
from like high school onward that, oh,
link |
everything in your body is designed
link |
to keep everything in balance.
link |
You stay awake for a certain amount of time,
link |
you want to sleep.
link |
You don't eat for a while,
link |
then you want to eat to maintain weight, right?
link |
You eat too much, then you want to eat less.
link |
Those systems are disrupted.
link |
And so what's so beautiful about this work
link |
from the Columbia group is that what it says is
link |
the place to intervene has to be the habit.
link |
This stuff has already passed through all the learning.
link |
It's passed through all the reward systems.
link |
It's clearly not being overrun
link |
by the homeostatic processes of the body.
link |
There's very little body fat.
link |
There's no leptin.
link |
Whatever neurons in the brain respond to leptin
link |
are starved for leptin.
link |
Periods have shut down,
link |
sperm production and testosterone is lowered.
link |
Bone density is down.
link |
Clearly this is overriding all those homeostatic processes,
link |
all the signals that would say, eat, eat, eat.
link |
Those don't matter in the brain of the anorexic.
link |
The brain of the anorexic is just performing habits
link |
and they're being rewarded for it.
link |
So when you come along and say, look,
link |
you should really eat this whole pie or this whole pizza,
link |
you'll feel better.
link |
That's actually aversive to them.
link |
So since it appears to be a habit,
link |
a reflex that's perpetuating the anorexic phenotype,
link |
as we say in science, it's perpetuating anorexia
link |
in this individual and telling them about
link |
all this terrible stuff that's happening in their body
link |
Taking them away from all the images of thin people online,
link |
et cetera, that's not going to work.
link |
What's going to work?
link |
What's going to work is intervening in the neural circuitry
link |
that's related to the habit itself.
link |
And it turns out that there are ways to do that.
link |
So how do you break a habit?
link |
How do you rewire the brain circuitry
link |
that's literally causing a reflex?
link |
And in this case, causing a reflex
link |
that is killing the individual,
link |
or at least leading to very bad health outcomes.
link |
The way that you do that is through a cognitive mechanism
link |
where you teach the individual
link |
what is leading up to the habit.
link |
This is a little bit similar to the way that
link |
somebody who suffers from addiction
link |
starts to put in different constraint type behaviors.
link |
Constraint type behaviors are the sorts of things like
link |
where the alcoholic will call a hotel ahead of time
link |
and say, listen, I want the mini bar taken out of the room.
link |
I don't want a television in the room, et cetera.
link |
Constraint type behaviors.
link |
Those are really ways of keeping oneself from the temptation
link |
but with these habits,
link |
they work at such a subconscious level
link |
that what seems to work best is a combination
link |
of teaching the individual about their internal state
link |
and how to register their internal state,
link |
what we call interoception,
link |
this ability to perceive your internal state
link |
so that they can start to learn to associate
link |
the interactions with different types of food
link |
with the sorts of cues that are occurring within their body.
link |
Quickening of heart rate, hyperacuity of focus
link |
that we talked about earlier.
link |
Once they start to be able to notice
link |
that those things are happening,
link |
then they can start to intervene.
link |
So let's talk about what those things are
link |
that lead into a habit
link |
because those turn out to be the exact points of entry
link |
for changing and eliminating and rewiring habits
link |
toward more healthy behaviors.
link |
And I should highlight that this isn't just about
link |
rewiring habits for sake of the anorexic.
link |
These are also the same types of mechanisms
link |
that one would want to incorporate
link |
in order to rewire any habit of any kind.
link |
There are two main features of thinking
link |
that go into the sorts of habits that anorexics execute.
link |
The first is something called weak central coherence.
link |
Weak central coherence is essentially an inability
link |
to see the forest through the trees.
link |
It's a hyperacuity and focus on details
link |
within a given environment.
link |
And there's actually an interesting probe test
link |
for anorexia that involves something akin
link |
to kind of a Where's Waldo type puzzle
link |
where an image is put up.
link |
The one that I saw was one in which
link |
there was a big array of coffee beans, actually.
link |
They're all brown coffee beans.
link |
And your job is to identify where in that array
link |
of coffee beans, there's a face.
link |
And indeed there's a face embedded in there.
link |
It looks a little bit like a coffee bean,
link |
but once you see it, you realize it's a face,
link |
not a coffee bean.
link |
And it becomes very hard to not notice the face after that.
link |
Anorexics are very good at identifying the face.
link |
They find it much faster than do non-anorexics,
link |
which is really interesting, right?
link |
They somehow are able to hone in on details
link |
and find those details and fixate on those details.
link |
Now, eventually most, if not all people find the face.
link |
But once you do, what you will find
link |
and what everyone finds is that you can't unfind the face.
link |
It just jumps out.
link |
So what essentially you've lost is the ability
link |
to see the whole picture because there's some detail
link |
within that picture that you're obsessed by.
link |
So this has kind of elements
link |
of obsessive compulsive disorder,
link |
but it's not really obsessive compulsive disorder per se.
link |
So we call that weak central coherence.
link |
It's a hyperacuity on one particular feature.
link |
You miss the big picture.
link |
The other is a challenge in set shifting
link |
that once you identify something
link |
that's of particular interest
link |
and that's driving some sort of reward for the anorexic,
link |
that would be identifying the high fat foods
link |
or identifying the one food on the table
link |
that one could eat without anyone hopefully noticing
link |
that they're eating just the green beans
link |
and not touching any of the other food.
link |
If you ever had a meal with an anorexic,
link |
you might be familiar with this.
link |
It's kind of uncomfortable to be around actually.
link |
They go through a lot of elaborate procedures
link |
to kind of hide food, to,
link |
they'll sometimes even chew food, hold it in their mouth
link |
and then go to the bathroom and discard it.
link |
Things very elaborate, very troubling types of things
link |
to hear about and to be around.
link |
But you'll notice that they push food
link |
around their plate a lot.
link |
They become masterful actually
link |
at trying to keep people's awareness
link |
away from what they're doing,
link |
which is to home in on these low fat, low calorie foods.
link |
And they can't seem to set shift.
link |
They can't just relax and enjoy the meal
link |
because the meal for them is essentially
link |
like this where's Waldo
link |
or find the face in the coffee bean task.
link |
They're constantly monitoring
link |
how much people are observing them
link |
and trying to navigate this
link |
what would otherwise be a really pleasant circumstance
link |
They're trying to navigate through this
link |
because remember for them,
link |
the reward is in the avoidance of certain things
link |
and the acquiring of only the foods
link |
that their brain rewards them for
link |
because those are the foods
link |
that have been pre-selected in our now habit.
link |
What's amazing and frankly also important
link |
are these findings that once you teach anorexics,
link |
what's happening to them,
link |
that they're doing this,
link |
they are able to intervene.
link |
Now they need support, right?
link |
And another form of therapy
link |
that seems to work well for anorexics
link |
that ideally is combined with this habit rewiring
link |
is a family-based model.
link |
Family-based models are starting to surface a lot now
link |
in various therapy settings.
link |
Therapy-based models in short
link |
are basically where the entire family
link |
is made aware of the individual's challenges
link |
with a particular eating disorder or other disorder.
link |
And in understanding some of the biology
link |
and psychology around it,
link |
they stop condemning the individual.
link |
They start to support that individual
link |
through queuing them towards their own habits
link |
that they observe.
link |
They give them some autonomy.
link |
They realize that none of this changes overnight
link |
but they're taught about things like neuroplasticity
link |
and the ability to change one's brain
link |
in response to experience.
link |
And so there's a whole internal support network.
link |
Now for people that live alone,
link |
this isn't available to them.
link |
This isn't the kind of thing
link |
that you share with your coworkers.
link |
You might involve a close friend or a spouse
link |
but it's not the sort of thing
link |
that people that don't live in a family context
link |
can really benefit from.
link |
All of these things fall under
link |
the umbrella of cognitive behavioral therapy.
link |
And I should mention that cognitive behavioral therapies
link |
are often done in conjunction with pharmacologic therapies.
link |
I think that there's this idea out there
link |
that it's either or when often it's both.
link |
So cognitive behavioral therapies are often combined
link |
with this habit recognition and rewiring approach
link |
which is starting to become more and more common.
link |
And I think the data on it look really good
link |
that especially when individuals
link |
are taught this early in adolescence,
link |
that there are positive outcomes over time.
link |
The relapse rate of anorexia is quite high.
link |
It's about 50% of individuals will relapse at some point
link |
often triggered by a stressful life circumstance.
link |
But the combination of cognitive behavioral therapy
link |
that includes this family model
link |
or at least habit reformation seems to be fairly effective.
link |
And at present might be the most effective treatment.
link |
Now there are additional treatments starting to surface
link |
and that takes us into the realm of chemical treatments
link |
for anorexia and I just want to mention
link |
that there are clinical trials,
link |
meaning legal clinical trials being done
link |
at Johns Hopkins School of Medicine
link |
by Matthew Johnson and others,
link |
exploring how drugs like MDMA,
link |
which increases dopamine and serotonin to very high levels
link |
or psilocybin, so-called magic mushrooms,
link |
which increases serotonin and other compounds
link |
to very high levels within the confines
link |
of a professionally supported therapeutic environment
link |
can help people rewire their brain
link |
such that they can get relief from major depression
link |
and various forms of trauma.
link |
And now eating disorders are also being explored
link |
in the context of MDMA and psilocybin clinical trials.
link |
I do want to emphasize that those are clinical trials,
link |
that those compounds are not yet legal.
link |
And in many cases, most cases, they are still illegal.
link |
I do not think that they should be explored
link |
without a properly trained medical doctor
link |
that the clinical trials are essential to complete
link |
before one explores those compounds in particular,
link |
because lately I get a lot of emails about these compounds,
link |
people telling me that they've had amazing experiences
link |
and relief from various things, not just eating disorders,
link |
but depression, et cetera.
link |
However, I get an equal number of emails from people saying
link |
that they worked with some self-appointed guide.
link |
This would be outside the clinical trials
link |
I was referring to,
link |
and they are now experiencing chronic visual snow.
link |
They're getting genuine visual field deficits.
link |
They are having ticks that they never had before.
link |
They have chronic insomnia.
link |
So I'm not passing judgment on any of these compounds
link |
or the people that are doing this sort of thing.
link |
I just want to see the clinical data.
link |
And I do believe that we should wait
link |
until these clinical trials are done
link |
before people start approaching this stuff.
link |
And that's because they are serious compounds.
link |
They can open plasticity,
link |
but whether or not they work, quote unquote,
link |
for different types of eating disorders
link |
or depression and trauma, the data are looking promising,
link |
but that the clinical trials are still not done.
link |
And I know a number of people are going out of the US
link |
and into other countries where this stuff
link |
is being done more regularly.
link |
And there too, I've gotten reports back
link |
of people doing so-called ibogaine treatments.
link |
Some of you who are familiar with eating disorders
link |
will immediately be asking, well, what about ibogaine?
link |
Does it work? Does it work?
link |
Well, the clinical trials in this country are not complete.
link |
I've heard evidence direct.
link |
I've heard directly from people who have benefited
link |
from the sorts of things for treatment of eating disorders.
link |
But I've also heard of people
link |
that have developed chronic seizure disorders
link |
from pursuing things like ibogaine
link |
for the treatment of eating disorders.
link |
So again, I'm not passing judgment.
link |
I would just like to see more data.
link |
And it's very important that the safety,
link |
aspects of safety be in place.
link |
So this is definitely not something to get renegade about.
link |
So it appears that once anorexia is established,
link |
that habit breaking through self-awareness
link |
of what the habits are is going to be a primary entry point.
link |
That might seem kind of trivial.
link |
You might say, well,
link |
couldn't you have just told us that in one sentence?
link |
But I want to return us to this model
link |
about homeostatic processes, reward processes, et cetera.
link |
That leads us to a place where the short answer is no.
link |
You can't simply say break the habit.
link |
An individual needs to be informed
link |
about where that habit comes from.
link |
And the fact that what currently seems like a rewarded habit
link |
should actually be a punished habit.
link |
Now, I don't mean by actual punishment,
link |
but what I mean is within the brain,
link |
there's been a switch and the anorexic
link |
needs to learn that there's been a switch
link |
such that what should be rewarding is now punished
link |
and what should be punished, starvation is now rewarded.
link |
The beauty of being a human being
link |
is that knowledge of knowledge
link |
can allow you to make better decisions.
link |
I'll say that again.
link |
The beauty of being a human being
link |
is that knowledge of knowledge
link |
can allow you to make better decisions.
link |
Now, of course, when we are anxious, when we are tired,
link |
when we are intoxicated, we have less access
link |
to that ability to use knowledge of knowledge to intervene.
link |
The anorexic will often do things
link |
that are in keeping with their habits,
link |
such as over exercising.
link |
This is a area that anyone who's treated anorexics
link |
or interacted with anorexics is well aware of
link |
that they are constantly moving.
link |
They're constantly on the treadmill.
link |
They're constantly running.
link |
They always want to be moving and burning calories
link |
so that they can feel okay about interacting with food
link |
or because they have the distorted body image.
link |
Well, does breaking a habit mean
link |
that they should stop moving around and exercising?
link |
No, not necessarily.
link |
There's some really interesting studies
link |
that show that shifting anorexics towards activities
link |
that, for instance, build muscle resistance training
link |
and allow them to eat a bit more food
link |
without necessarily losing weight,
link |
but rather to put more muscle on their body
link |
can actually be beneficial.
link |
Now, I'm not talking about anorexics becoming bodybuilders.
link |
There's a whole body dysmorphia associated
link |
with bodybuilding,
link |
but certain forms of exercise are just catabolic,
link |
meaning they break down the amount of muscle.
link |
They reduce body weight overall.
link |
Other types of exercises like resistance training
link |
They allow muscle to be put on.
link |
And there are some interesting studies,
link |
not a lot, but some interesting studies
link |
trying to encourage anorexics not to stop exercising,
link |
but rather to stop exercising in this neurotic catabolic way
link |
of breaking oneself down,
link |
but rather getting them shifted toward breaking habits
link |
of only approaching low calorie, low fat foods,
link |
while also encouraging them to embark
link |
on resistance training
link |
and to start to learn and reward the relationship
link |
between exercise for sake of making one's body strong,
link |
including the bones, not just the muscles, but the bones,
link |
which is important, especially in anorexics,
link |
and then to see food as a way to nourish that process,
link |
to building a body that could be of the stable weight,
link |
hopefully once the anorexic is of a healthy weight
link |
that they're maintaining that weight,
link |
but that they don't have to constantly be on this treadmill,
link |
of balancing whatever food intake they have with activity.
link |
And along the lines of that,
link |
during the episode on fat loss and metabolism as well,
link |
I talked about this NEAT
link |
and non-exercise induced thermogenesis,
link |
where people who tend to be thin,
link |
tend to bounce around a lot, they're kind of fidgety,
link |
and that burns thousands of calories a day,
link |
anywhere from 800 to 2000 calories a day.
link |
Now that can be beneficial for the folks
link |
that are overweight and have a healthy mindset about food,
link |
but are trying to lose weight.
link |
And it turns out that by literally fidgeting
link |
and bouncing around like,
link |
this is why I'm doing this, it looks ridiculous,
link |
you actually burn a lot of body fat and calories that way,
link |
provided you're in a caloric deficit,
link |
you burn body fat,
link |
because body fat is not just a passive tissue,
link |
it actually receives input from neurons
link |
that release noradrenaline and adrenaline.
link |
And this NEAT has been described for several decades now,
link |
and it actually is a pretty terrific way
link |
to burn off more calories.
link |
So with the anorexic,
link |
you actually want to encourage them
link |
to not constantly be trying to burn off calories,
link |
that can be very challenging.
link |
So shifting them toward activities
link |
like weight-bearing activities or resistance training
link |
that promote this more anabolic type of relationship
link |
to activity as opposed to catabolic can be beneficial.
link |
Before we move on to talking about bulimia
link |
and some related disorders,
link |
I want to talk about an aspect of anorexia
link |
that's very interesting, quite troubling in fact,
link |
but that has received a lot of attention,
link |
and that's the distorted self image.
link |
Now, in the episode on depression,
link |
we talked about a very powerful aspect of major depression,
link |
which is this anti-self-confabulation
link |
that people who are depressed seem to genuinely believe
link |
and even confabulate about the fact
link |
that they are performing poorly in life
link |
and that they are no good or worthless, et cetera.
link |
It's literally a lie that they believe
link |
and their statements and their feelings
link |
and their behaviors start to reflect that lie.
link |
They're not conscious of it.
link |
That's why we call it a confabulation.
link |
Anorexics often will see themselves as overweight
link |
or imperfect in ways that are of an obsession for them.
link |
They'll think, oh, you know,
link |
their arms are a little bit fat, you know,
link |
or, you know, the contour of their face makes,
link |
they don't like the pictures of themselves or they,
link |
what I'm describing here is actually pretty typical behavior
link |
of a lot of people.
link |
I mean, how many people do you know
link |
that after you take a picture of them,
link |
they say, can I see the picture?
link |
And then they tell you that you have to throw it away.
link |
That doesn't necessarily mean they're anorexic
link |
or they're suffering from some sort of disorder.
link |
That just means that they're a human being
link |
that cares about how they appear in the world.
link |
We're not here to judge that.
link |
In the case of the anorexic,
link |
the problem seems to be that they have a genuine distortion
link |
of their self-image so much so
link |
that they don't actually see themselves accurately.
link |
Their visual perceptions are off.
link |
And the reason we know this
link |
or it's because of some really important
link |
and beautiful studies that were done
link |
in my colleague Jeremy Bailenson's lab at Stanford.
link |
He's in the department of communications.
link |
He's actually collaborated with a Dr. Halpern
link |
that I mentioned earlier.
link |
What's really interesting about these studies
link |
is they give us a window into the perceptual defect
link |
that anorexics have.
link |
I've actually done one of these experiments.
link |
I'm fortunate to not be anorexic,
link |
but I've done some work with the VR lab over there.
link |
And what you get to do is you get to adjust
link |
this avatar of yourself to the point
link |
where you think it's as accurate as it could possibly be.
link |
And anorexics really distort this avatar.
link |
In other words, they create this serious mismatch
link |
between their perception of themselves and the reality.
link |
So indeed it does seem to be the case.
link |
Now what's relieving, or I should say what's encouraging
link |
about some of the therapies that we talked about before,
link |
the family-based model, the cognitive behavioral treatments,
link |
yes, and the drug treatments as well,
link |
but this habit intervention model
link |
is that as one starts to shift those things,
link |
it does appear that the perception of self seems to follow,
link |
that the perception of self seems to shift
link |
along with the change in habits.
link |
And that's a relief, at least I find that reassuring
link |
because changing one's perception is actually very hard.
link |
As somebody who's worked almost his entire career
link |
on visual perception and related things,
link |
the perceptual apparatus of the brain
link |
are not very amenable to neuroplasticity.
link |
Mainly they don't change that easily.
link |
Whereas it appears that the circuitry
link |
that's related to habit formation and decision-making
link |
and the reward circuitry, that stuff can be rewired.
link |
as they progress out of their anorexic state
link |
into one which they are intervening in their reflexes,
link |
gaining better habits around food,
link |
eating more accurately, assessing foods and environments
link |
that they're in related to food,
link |
as they change their behavior
link |
and they start to put on healthy weight,
link |
maybe they're also doing the sorts of exercises
link |
that allow them to put on healthy weight
link |
and avoiding kind of extreme exercises of catabolism
link |
and breaking themselves down.
link |
They also manage to somehow,
link |
just as a consequence of all that,
link |
rewire their perception of self.
link |
So it doesn't seem that trying to tell someone,
link |
oh my gosh, you're so thin, you really need to eat,
link |
that doesn't seem to work.
link |
They just don't see themselves the same way
link |
that you see them.
link |
And so I offer that as a point of consideration
link |
if you know someone that's anorexic
link |
or if you look at an anorexic and you think,
link |
how is it that they are still critical of the small,
link |
even non-existent amount of body fat
link |
on their triceps or something, how is that?
link |
Well, it's literally that their brain,
link |
as it relates to perceptions,
link |
visual perceptions in particular,
link |
that they're completely off.
link |
And fortunately, by changing habits,
link |
you rewire those circuits as well.
link |
Okay, so let's talk about bulimia,
link |
which is overeating and then purging,
link |
typically by self-induced vomiting
link |
or by ingestion of laxatives,
link |
sometimes also in concert with people taking stimulants
link |
and fat burners and over-ingestion of stimulants
link |
to try and burn off more energy.
link |
And then we'll also talk about binge eating disorder,
link |
which has a lot of the same features as bulimia,
link |
but typically no purging.
link |
I'm not going to list off all the clinical criteria
link |
that would allow someone to be diagnosed
link |
as bulimic or binge eating disorder.
link |
But the general features are that they ingest
link |
far more calories than they need,
link |
anywhere from 10 to 30 times their daily caloric intake,
link |
oftentimes within a two-hour period,
link |
which is just a staggering amount of food and nutrients
link |
in a short period of time.
link |
Oftentimes they're overriding those mechanical signals
link |
from the body that they're full.
link |
It's a really troubling thing to think about,
link |
but people are literally gorging themselves with food.
link |
This looks a lot like a laboratory animal
link |
that has these AGRP neurons stimulated,
link |
these neurons that will eat until they almost burst
link |
So you wonder, is it these AGRP neurons that are active?
link |
Almost certainly, yes, that they're involved.
link |
Although I don't think that that's going to be
link |
the major point of intervention,
link |
that we're going to talk about other types of interventions.
link |
There are a number of clinical criteria.
link |
For instance, if somebody has one of these binges
link |
once a year, does that make them bulimic?
link |
Technically, no, but I certainly don't recommend
link |
If you are one of these people
link |
who has so-called cheat days, right?
link |
Some of you may be familiar with cheat days.
link |
I think they're a little less common now,
link |
but the idea is you eat clean for six days
link |
or five days a week or two weeks,
link |
and then you have a so-called cheat day
link |
where you just kind of go wild and eat whatever you want
link |
and whatever volumes.
link |
Is that bulimia? It has some of the contour of bulimia.
link |
If you're vomiting afterwards or binge eating disorder,
link |
if you're not, does it constitute full blown bulimia
link |
or binge eating disorder?
link |
It's pretty hard to say.
link |
The criteria that were described to me
link |
is that if somebody is doing this at least once a month
link |
over a period of anywhere from two to three months,
link |
then it likely would qualify.
link |
And I certainly know people who do these cheat days
link |
and by those criteria,
link |
they have something like binge eating disorder.
link |
But in general, one of the hallmark features
link |
of bulimia and binge eating disorder
link |
is that people are unable to control their eating.
link |
They're just simply,
link |
they're not making the decision to have a cheat day.
link |
They're not making the decision to overeat.
link |
They are simply driven from the inside
link |
without question by way of neural circuitry.
link |
They are driven from the inside
link |
to ingest far more food than they need.
link |
And in some cases, then they would want to eat.
link |
So it's a lot like the habit
link |
that we described for anorexia.
link |
It's almost like it's turned into a reflex
link |
once they get going.
link |
All the homeostatic signals are being overridden.
link |
All the signals from the body, the leptin,
link |
the insulin, the glucose,
link |
all that stuff is cosmically sky high.
link |
And yet they're just what the nerds call hyperphagic.
link |
They're just eating like crazy.
link |
So what's going on there?
link |
Well, there've been a lot of ideas, you know,
link |
about why this arises.
link |
There's the so-called thyroid hormone hypothesis.
link |
That one's a tricky one.
link |
It turns out that cortisol
link |
and thyroid hormone concentrations vary
link |
according to when the binge purge happened.
link |
So there were some studies
link |
that looked at thyroid hormone levels
link |
and they found elevated thyroid hormone levels.
link |
Thyroid hormone is involved in metabolism
link |
and not just the burning of energy,
link |
but the use of energy in converting it
link |
to different tissues of the body,
link |
cartilage, bone, fat, and muscle, et cetera.
link |
Did a whole episode on thyroid and growth hormone,
link |
by the way, if you're interested
link |
in learning more about thyroid hormone.
link |
But thyroid hormone can also be depleted
link |
at other phases of the binge purge cycle.
link |
Now, without listing off all the terrible things
link |
that happen with this binge purge cycle,
link |
there are a number of things
link |
that are really worth pointing out.
link |
One is that the vomiting itself, the use of laxatives,
link |
that can cause severe disruption to the mucosal lining,
link |
the mucus lining of the digestive tract,
link |
can severely disrupt the gut microbiome.
link |
It can cause all sorts of even ulceration of the esophagus
link |
and just really terrible stuff.
link |
There's a lot of shame associated with bulimia,
link |
oftentimes because people are vomiting
link |
and it's hard to hide that vomiting behavior.
link |
People are aware of it.
link |
There's some social isolation.
link |
So you recall from the beginning,
link |
it does not appear that sexual trauma
link |
is a prerequisite for bulimia,
link |
although sometimes it can occur.
link |
The hallmark feature of bulimia
link |
that distinguishes it from anorexia,
link |
aside from the fact that it's overeating
link |
as opposed to undereating,
link |
is a lack of what they call inhibitory control.
link |
And that might come as no surprise.
link |
But first of all, the bulimic, unlike the anorexic,
link |
is hyper impulsive
link |
and oftentimes has other types of impulse behaviors.
link |
They might have a little bit of alcohol
link |
and then start to eat like crazy,
link |
whereas normally they're very restrictive.
link |
That's a common feature of bulimia.
link |
Sometimes they over ingest alcohol during these binges.
link |
Sometimes they are sexually promiscuous, not always,
link |
but it's a general issue with satiety
link |
once they start eating
link |
and with impulse control generally.
link |
And for that reason,
link |
many of the treatments that you see for bulimia
link |
and binge eating disorder
link |
are the sorts of treatments that don't seem to work so well,
link |
or at least most of the time for anorexia.
link |
So the drugs that increase the neuromodulator serotonin,
link |
for instance, fluoxetine,
link |
also called Prozac, Paxil, et cetera,
link |
those things oftentimes can be effective in bulimia.
link |
Some of the drugs that are used to treat
link |
attention deficit hyperactivity disorder and ADD,
link |
a topic that we're going to talk about in depth
link |
here on the podcast soon,
link |
some of those same drugs like Adderall,
link |
Vyvanse and things of that sort
link |
can also be used to treat bulimia and binge eating disorder.
link |
Why would that work?
link |
Well, now you are familiar with the prefrontal cortex.
link |
You probably know more about prefrontal cortex
link |
than you ever wanted to.
link |
Just from this episode,
link |
prefrontal cortex is involved in this analysis
link |
of duration, path and outcome.
link |
Duration, path and outcome is how we avoid impulsivity.
link |
It's how we think, okay, if this, then that,
link |
if that, then this,
link |
you can imagine how for the obsessive compulsive
link |
or for the anorexic,
link |
these are circuits that are overactive.
link |
this is the circuit that's going to essentially
link |
be underactive and is under conditions where they think,
link |
oh, you know, I shouldn't eat anything.
link |
I shouldn't eat anything.
link |
And then they just tear the refrigerator open
link |
and plow through that.
link |
And then at that point they're plowing through the cupboards
link |
and then they're ordering food
link |
and then they're feeling horrible about themselves.
link |
There do tend to be these cycles of binge and purge
link |
followed by feelings of real shame
link |
because they just can't control their behavior.
link |
And what is more embarrassing
link |
than not being able to control one's behavior as an adult
link |
or as a young adult.
link |
So really the polar opposite of what you see
link |
So this lack of impulsivity
link |
implies a lack of prefrontal control,
link |
what we call top-down control.
link |
Why do we call it top-down?
link |
Because the prefrontal cortex is suppressing the activity
link |
of deeper limbic and hypothalamic circuitry
link |
and things of that sort.
link |
Anytime you feel like you want to say something
link |
really offensive and you don't,
link |
that's top-down control.
link |
That's your prefrontal cortex.
link |
Anytime someone says something and you like,
link |
like grit your teeth,
link |
cause you know you shouldn't say anything,
link |
gritting your teeth is top-down control.
link |
When you explode or burst or say the wrong thing
link |
or say the thing that you shouldn't say
link |
or do the thing you shouldn't do,
link |
that's lack of prefrontal control.
link |
And indeed people who have frontotemporal dementia
link |
due to aging or head injuries see this a lot
link |
and people play sports that get a lot of frontal damage,
link |
they become more impulsive.
link |
So bulimics have an issue with impulsivity
link |
and therefore drugs that can increase serotonin
link |
and sometimes these drugs that increase dopamine
link |
and adrenaline also called epinephrine
link |
will increase the tone as we call it,
link |
the dopaminergic tone or the norepinephrine,
link |
it's called adrenergic,
link |
but norepinephrine levels in the brain
link |
allow for more top-down control.
link |
And that's also why they're used to treat ADHD
link |
and attention deficit disorder.
link |
They tend to create a hyper-focus.
link |
They tend to push the brain into,
link |
these drugs tend to create a hyper-focus
link |
and tend to push the brain and general mode of processing
link |
into one in which you think, if this, then that,
link |
if this, then that.
link |
So anticipating outcomes.
link |
And for that reason, drugs like Wellbutrin, Bupriarone,
link |
which is an antidepressant,
link |
which mainly increases the amount of dopamine
link |
and norepinephrine and less so serotonin,
link |
that can also be effective
link |
for certain types of binge eating disorder
link |
and is actually used to treat smoking
link |
for promoting smoking cessation and for depression,
link |
but also for certain forms of obesity
link |
related to binge eating disorder.
link |
And the data are pretty good
link |
and there are timed release forms of this
link |
and non-timed release forms.
link |
And I think you have to consult with a psychiatrist
link |
in order to get these prescribed
link |
because they are prescription drugs,
link |
but it's a very different constellation of neurochemicals
link |
and brain areas and approaches for bulimia.
link |
The treatment of binge eating disorder
link |
has been explored from a new standpoint recently,
link |
and that's the work of this now, sadly,
link |
former colleague of mine, Dr. Casey Halpern,
link |
who's at University of Pennsylvania
link |
that I mentioned earlier.
link |
They are using deep brain stimulation
link |
in order to treat binge eating disorder.
link |
Now, why deep brain stimulation?
link |
Well, work from Dr. Halpern and others while at Stanford
link |
showed that there are particular patterns of brain activity
link |
in both the prefrontal cortex,
link |
but also in an area of the brain
link |
called the nucleus accumbens,
link |
very important and very relevant area of the brain
link |
And in any discussion about motivated behaviors of any kind,
link |
feeding, sex, drug related behavior,
link |
people exercise compulsively,
link |
the nucleus accumbens is in a ongoing dialogue
link |
with the prefrontal cortex.
link |
And the nucleus accumbens has no mind of its own,
link |
but it's associated with dopamine release.
link |
It's part of this so-called reward pathway.
link |
And what Dr. Halpern and colleagues discovered
link |
is that there are particular patterns of activity
link |
that ripple through the brain
link |
through these prefrontal networks
link |
and through this nucleus accumbens area,
link |
those areas are connected.
link |
It's called delta oscillations,
link |
delta just being a particular frequency
link |
of electrical activity for you,
link |
aficionados is one to four Hertz activity.
link |
But in any case, those delta oscillations
link |
in the nucleus accumbens are associated with food reward
link |
in both mice and humans.
link |
Somehow this reverberatory activity
link |
creates a perception in the individual
link |
that food is hyper rewarding.
link |
That's interesting and has allowed them to use
link |
a targeted deep brain stimulation approach
link |
to treat binge eating disorder.
link |
And this deep brain stimulation
link |
is appearing to be an effective treatment.
link |
There's still more studies that need to be done.
link |
Actually, if you think you have binge eating disorder,
link |
you can find the criteria for that
link |
and you could contact Dr. Halpern.
link |
As I mentioned, he's moving to University of Pennsylvania.
link |
They are recruiting patients for these studies all the time.
link |
The studies are fairly invasive.
link |
They involve a FDA approved approach
link |
of literally placing a wire down into an area of the brain
link |
that then allows the individual
link |
to stimulate a particular brain area
link |
to offset some of these activity patterns
link |
that lead to a elevated sense of reward
link |
from food and binge eating.
link |
And the data look really promising.
link |
Now I realize that's a very invasive approach.
link |
Not everybody is going to be willing
link |
to have this wire inserted into the brain,
link |
but for people that suffer from binge eating disorder,
link |
this is a great and very exciting potential treatment
link |
because what I didn't tell you
link |
is that many people have binge eating disorder are obese
link |
to the point where their health is greatly at risk.
link |
Now, obesity causes all sorts of shifts
link |
in the dialogue between the brain and body,
link |
some of which you'll recognize
link |
from earlier in the discussion.
link |
For instance, leptin signaling is disrupted.
link |
So the fat, there's lots of body fat,
link |
but even though that body fat
link |
is secreting this hormone leptin
link |
and that signal should shut down the desire to eat,
link |
the receptors to leptin in the brain are totally screwed up.
link |
And so the signal to eat is there,
link |
but the signal to stop eating is not there.
link |
So again, you have an accelerator and a brake
link |
and it's like the accelerator is always pushed down.
link |
Some of these brain stimulation approaches
link |
seem to be able to bypass some of that.
link |
And of course, there are all the metabolic syndromes
link |
and the problems with having excess levels of body fat,
link |
things like insulin resistance, type two diabetes.
link |
I mean, as disturbing as is to hear,
link |
there are many individuals, actually,
link |
I know some who are so obese
link |
that they start getting bodily sores.
link |
They're not just bed sores,
link |
but they have skin sores that are very disruptive to them.
link |
They don't like having these sores.
link |
And in addition to that,
link |
they can get peripheral neuropathies
link |
because of some of these metabolic issues,
link |
they're not getting enough utilization of the nutrients
link |
in the tissue because the way that insulin is disrupted,
link |
insulin signaling, and they actually have to have
link |
certain portions of their limbs amputated
link |
and yet they continue to overeat.
link |
So this is not an issue of self-control
link |
that can easily be dealt with
link |
simply by telling the person, look,
link |
you have to stop eating or you're going to die
link |
or you're going to have your legs amputated.
link |
Like with anorexia,
link |
there's a distortion in the relationship to food,
link |
but the homeostatic and the reward aspects are disrupted.
link |
So unlike anorexia,
link |
where it seems to be a habit-based mechanism,
link |
with bulimia and binge eating disorder,
link |
something deep within the neural circuitry
link |
is causing food to be hyper attractive
link |
and the break is off.
link |
So if you want to develop some empathy
link |
for what these people are dealing with, consider this.
link |
It's like driving a car.
link |
You get onto a grade, maybe a 10 or 15 degree grade,
link |
and you're heading down and you figure,
link |
well, you'll just pump the brakes a little bit,
link |
but there is no break, right?
link |
So you start going faster and faster and faster,
link |
and your only choice is to use the accelerator
link |
or just to coast through it.
link |
That's essentially what's happening to these neural circuits.
link |
So the work of Dr. Halpern and others,
link |
I think is really exciting.
link |
And even though it's highly invasive,
link |
I think it's going to lead to
link |
not just some relief for the patients
link |
that do get that deep brain stimulation,
link |
but also the identification of what sorts of receptors
link |
are present in those brain areas
link |
What that means is that once we understand
link |
which brain areas are involved in the disorder,
link |
and we understand what receptors those brain areas express,
link |
then there can start to be additional interventions
link |
by way of non-invasive treatments,
link |
things like drug treatments.
link |
Do behavioral interventions work for bulimia?
link |
In some cases, yes,
link |
provided that those interventions are done early enough.
link |
Regardless, behavioral interventions
link |
coupled with drug-based interventions
link |
are always more effective than either one alone.
link |
Fortunately, there is a decent size kit of drugs
link |
that can help with bulimia.
link |
I mentioned some of them before,
link |
things like buprenorphine, wellbutrin,
link |
some of the serotonergic drugs,
link |
and some of the drugs used to treat impulsivity.
link |
So we have on the one hand anorexia,
link |
which seems to be a disruption in habit
link |
and a coupling of unhealthy habits,
link |
in this case, food restriction,
link |
to the reward pathway.
link |
And on the flip side,
link |
we have binge eating disorder and bulimia,
link |
where a very unhealthy habit of gorging oneself with food,
link |
sometimes followed by purging,
link |
is not necessarily coupled to reward.
link |
They feel terrible when they do that, right?
link |
The anorexic feels great about restricting their food intake.
link |
They feel like they're winning some sort of game.
link |
The circuitry is flipped somehow that way.
link |
With bulimia, they feel horrible about the fact
link |
that they're binging.
link |
There's immense shame.
link |
They can't control themselves.
link |
The reward is set up before the behavior.
link |
The reward is set up in drawing them to food
link |
and in making food look like something
link |
that's incredibly appetizing,
link |
and there's no impulse break.
link |
There's no way for them to stop that kind of behavior.
link |
So a really kind of troubling thing to think about,
link |
in either case, I think for those of us that know anorexics
link |
or have observed anorexia,
link |
it's so hard to see somebody starve themselves
link |
to near death or to death.
link |
What more could be disturbing?
link |
Well, equally disturbing is somebody who has an abundance
link |
of food and is gorging themselves
link |
and then feels terrible about it.
link |
So these are heavy topics.
link |
These are topics that frankly,
link |
no one really wants to talk about
link |
unless they know someone who's suffering from them
link |
or they themselves suffer from them.
link |
What I've tried to do today is try and give you a window
link |
into what really underlies these things
link |
that we call eating disorders.
link |
I hope I've done that at the level of biology,
link |
neurocircuitry, mechanism, endocrinology,
link |
and some of the psychology.
link |
As with any episode of this podcast,
link |
but especially in this month
link |
where we're talking about mental health issues
link |
and mental health disorders, behavioral disorders,
link |
there's no way that I can exhaustively cover
link |
all the different forms of treatment.
link |
You have the model approach.
link |
You've got all these different approaches
link |
to depression and to anorexia, et cetera.
link |
What I've tried to do is give you a framework.
link |
And in doing that,
link |
I've tried to give you a framework of understanding
link |
that also applies to this question
link |
that's I think equally important
link |
and goes alongside the treatment of eating disorders
link |
is what in the world is healthy eating?
link |
What in the world is a healthy relationship to food?
link |
I like to think that I have a healthy relationship to food.
link |
I know the foods I like, I enjoy them.
link |
There are 10 or 15 foods in particular
link |
that I like very much.
link |
I've mentioned a few of them on the podcast before
link |
and was sort of amused, surprised, and perplexed
link |
as to why, for instance, I do enjoy eating butter,
link |
not in huge amounts, but I do like butter.
link |
So that seemed to be pretty triggering
link |
for folks out there.
link |
A small selection of people decided
link |
that the ingestion of butter was a health concern.
link |
Look, to me, ingesting butter in small quantities
link |
is something that I'm comfortable with
link |
and my blood lipid profiles feel good.
link |
They look good to me.
link |
For other people, that might not be the case.
link |
For some people, the idea of eating an animal-based food
link |
is probably so repulsive
link |
that it actually can make them feel physically sick.
link |
And I think that we should be aware
link |
that that kind of mental phenotype exists.
link |
I'm not calling it a pathology.
link |
For other people like myself,
link |
things like butter and meat feel healthy.
link |
Now, what quantities?
link |
Well, I enjoy eating very much.
link |
I'm not shy about this.
link |
I've talked about it in the podcast before.
link |
Some people have a very complicated relationship to food.
link |
They don't think of it as nourishment.
link |
They don't enjoy it socially.
link |
It's a stressful thing for them
link |
based on their personal history
link |
or maybe just general anxiety around food.
link |
And I hope that in sharing this information
link |
about the fact that anytime we approach food,
link |
these neurons in the arcuate area of our hypothalamus
link |
actually increase our levels of anxiety.
link |
This is related to that point that Dr. Halpern made,
link |
which was that from an evolutionary standpoint,
link |
it is advantageous to ingest as much food
link |
as often as possible, as quickly as possible.
link |
We now know that to not be healthy in this age of abundance
link |
where calories are essentially everywhere.
link |
And yet a lot of people feel anxious
link |
in anticipation of a meal.
link |
What could be useful to them?
link |
Well, whether or not they have an eating disorder or not,
link |
it's very clear that developing methods to calm oneself
link |
in the presence of any anxiety or fear inducing stimulus
link |
can be beneficial.
link |
I've talked about some of these
link |
in episodes related to stress,
link |
things like the physiological side,
link |
two inhales through the nose and a long exhale.
link |
Things like mindfulness meditation certainly can help.
link |
There are data, a lot of studies out there
link |
showing that meditation practice can help people deal with
link |
eating related anxiety and disorders.
link |
I think as a general rule,
link |
trying to avoid approaching a meal or sitting down to eat
link |
in an anxious state is probably a good idea,
link |
but let's be realistic.
link |
How often can we do that?
link |
I think most of us are going to have circumstances
link |
where we're rushing around trying to just eat
link |
before we head out or get to a meal.
link |
And then we sit down and we find ourselves eating.
link |
This is one of the first times in human evolution
link |
where we mostly eat out of a desire to consume food,
link |
not out of a need for food.
link |
Most everybody could go a fairly long period of time
link |
just ingesting water and electrolytes
link |
and not that I'm suggesting people do that,
link |
but let's face it.
link |
We largely eat nowadays because of a desire to eat,
link |
not a need to eat.
link |
And yet we need to eat on a fairly regular basis.
link |
And so no topic is more complicated and nuanced
link |
than food and nutrition.
link |
And in particular, as it relates to eating disorder.
link |
So the major takeaways today are,
link |
we should all be asking the question,
link |
what is healthy eating for us?
link |
How do we develop a relationship to food
link |
that we can enjoy food,
link |
hopefully both socially and on our own,
link |
but that we are not neurotic and compulsive about it.
link |
For those of you that intermittent fast,
link |
this also applies, right?
link |
What, you know, God forbid,
link |
if you eat 30 minutes before your eating window starts,
link |
what does that mean?
link |
If it means something catastrophic,
link |
do you have an eating disorder?
link |
I don't know, maybe you have an anxiety disorder.
link |
That's for you to explore.
link |
If you don't manage to eat five meals a day
link |
and that's your obsession,
link |
well then, you know, the same thing applies.
link |
These are questions that we can all ask ourselves.
link |
Today, we focus on the extremes of food-related behaviors
link |
that really qualify as genuine disorders.
link |
They are in the psychiatric manuals and they are diagnosable
link |
and they are serious health concerns.
link |
They're not just mentally troubling and concerning
link |
for the people suffering from them
link |
and the people around them,
link |
but they are genuine health concerns.
link |
Just want to reiterate that anorexia nervosa
link |
is the most deadly psychiatric disorder by a huge margin.
link |
And if you look statistically at the number of people
link |
with eating disorders and that die of eating disorders,
link |
it's not far off from the number of people
link |
that die from automobile accidents.
link |
I know that that sounds like a ridiculous number,
link |
but you can look this up.
link |
This is particularly true in certain countries.
link |
Why that is, we don't know.
link |
But again, this is not a new phenomenon.
link |
This is not just related to body image issues
link |
that are created through social media and media.
link |
And as a final point on that, many of you
link |
are probably asking, what about plastic surgery?
link |
What about all the steps that people are going to through,
link |
excuse me, to preen themselves and change themselves?
link |
Are people addicted to plastic surgery?
link |
Is that a form of body dysmorphia?
link |
And so we will do an episode on exercise-related
link |
and plastic surgery-related body dysmorphia.
link |
I think there is very little question
link |
that those types of disorders are clearly related
link |
to what we're observing in social media and in media,
link |
that this shift of, for instance, action heroes,
link |
if you look at action heroes in the 80s,
link |
there were very few men that were very large.
link |
You had your Stallone's and your Schwarzenegger's
link |
and a few others, but the men in movies tended to be,
link |
if they were muscular, they were far more svelte
link |
than they are now.
link |
There's this kind of, there's literally a hypertrophy
link |
And likewise, there's been hypertrophy
link |
of the female body shape as it's portrayed in the media.
link |
There are body dysmorpheas that are related
link |
to those types of things and that relate to things
link |
like plastic surgery, steroid abuse, diet drug abuse,
link |
Definitely important to think about and consider
link |
and definitely deserving of its own episode.
link |
You've learned a lot of neuroscience today.
link |
I hope that was useful in thinking
link |
about these disorders and in thinking about other aspects
link |
of feeding and motivated behaviors.
link |
I would love for you to take away this model
link |
that was handed off to me that I think is so powerful
link |
for thinking about all sorts of things, not just eating,
link |
but all kinds of behaviors and perceptions
link |
that you have one box for what you think,
link |
one box for what you do,
link |
and what is intervening between those?
link |
Why is it that you can know better and not do better?
link |
Well, it's because you also have to cope
link |
with the subconscious homeostatic processes
link |
and reward processes.
link |
And those oftentimes can be disrupted in ways
link |
that we find ourselves doing things that are not good
link |
for us or not good for other people.
link |
But fortunately there is this great gift,
link |
which is that knowledge of knowledge can allow you
link |
to do better without question.
link |
And that knowledge of knowledge allowing you
link |
to do better over time leads
link |
to this incredible phenomenon called neuroplasticity,
link |
which essentially is translated
link |
into doing better over time, even if difficult,
link |
eventually makes doing better reflexive.
link |
If you're enjoying this podcast and learning from it,
link |
please subscribe to our YouTube channel.
link |
That's Huberman Lab on YouTube.
link |
And there you can also leave us comments and feedback
link |
and suggestions for future topics and future guests
link |
for the Huberman Lab podcast.
link |
As well, we hope that you will subscribe
link |
on both Apple and Spotify.
link |
And on Apple, you have the opportunity to leave us
link |
up to a five-star review
link |
and to give us feedback there as well.
link |
Please also check out the sponsors mentioned
link |
at the beginning of the podcast.
link |
That's a terrific way to support the podcast.
link |
And if you'd like to support research on stress,
link |
human performance, sleep, and so forth,
link |
you can go to Hubermanlab.stanford.edu.
link |
And there there's a tab that you can click
link |
if you'd like to make a tax deductible donation
link |
to the laboratory to explore the sorts of things
link |
that relate to neural circuits, stress,
link |
sleep, and human performance.
link |
Not today, but oftentimes on this podcast,
link |
we discuss various compounds and supplements
link |
that people could possibly take in order to help deal
link |
with anxiety, improve gut microbiome,
link |
improve their sleep, et cetera.
link |
We didn't discuss those today,
link |
but for those of you interested in those compounds,
link |
if you want to see the ones that I take,
link |
you can go to Thorne, that's T-H-O-R-N-E.com
link |
slash the letter U slash Huberman.
link |
So it's Thorne.com slash U slash Huberman.
link |
See all the supplements that I take,
link |
you get 20% off any of those supplements.
link |
And if you enter the Thorne site through that portal,
link |
you can get 20% off any of the supplements that Thorne makes.
link |
We partnered with Thorne
link |
because they have the highest levels of stringency
link |
with respect to the quality of ingredients,
link |
the precision of the amounts of those ingredients.
link |
And while supplements are certainly not required
link |
or necessary for anything really,
link |
you can always use behavioral tools.
link |
Many people benefit from taking supplements of various kinds
link |
and we do believe that getting supplements
link |
of the very highest quality is going to be important
link |
if that's the decision for you.
link |
And last but not least,
link |
I want to thank you for your time and attention
link |
and thank you for your interest in science.
link |
Thank you for your time and attention and thank you for your time and attention.