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welcome to the huberman Lab podcast where we discuss science and science-based tools for everyday life
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I'm <PRESIDIO_ANONYMIZED_PERSON> and I'm a professor of neurobiology and Ophthalmology at Stanford school of medicine today my
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guest is Dr Sachin Panda Dr Sachin panda is a professor and director of the regulatory biology laboratory at the
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Salk Institute of biological studies his laboratory has made numerous important contributions that impact
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mental health physical health and human performance for instance his laboratory discovered the neurons in the eye and
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neurons within the brain that regulate our so-called circadian rhythm circadian rhythms are 24-hour rhythms and
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everything from gene expression to the overall functioning of tissues our levels of mood and alertness our ability
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to sleep appetite and much much more in addition over the last decade Dr Panda's
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laboratory has made critical discoveries in terms of how our patterns of eating over time impact our biology and our
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health in particular his laboratory Pioneer discoveries related to so-called intermittent fasting also sometimes
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referred to as time restricted feeding today Dr Panda and I discuss how our circadian behaviors everything from when
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we wake up to when we view light to when we avoid viewing light to when we eat and what we eat and when we socialize
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and how we socialize impacts our biology and our psychology energy and how all of
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that has a strong impact on our health during today's discussion you will learn how restricting your feeding to specific
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periods within each 24 hour cycle or perhaps even exploring longer patterns
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of fasting and eating Cycles can impact everything from the health of your liver to your gut to your brain and how all of
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that impacts things like mood and your ability to perform cognitive work indeed
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today's discussion goes deep into all aspects of intermittent fasting AKA time restricted feeding we talk about the
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basic science as well as the recent clinical trials that have explored time-restricted feeding in a diverse
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range of people including men women children people with diabetes people who
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are otherwise healthy and much much more I'm quite aware that intermittent fasting is a topic of much debate these
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days we go deep into that debate and by the end of today's discussion you can be certain that you will have learned all
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the latest and all the details all all made very clear to you thanks to the incredible expertise Discovery and clear
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communication of Dr Panda as some of you may already know Dr Panda has authored several important books on the topic of
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intermittent fasting and how it can benefit various aspects of Health those books include the Circadian code and a
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more recent book the Circadian diabetes code both of which we've provided links to in the show note captions in addition
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if any of you are interested in learning more about Dr Panda's work including seeing his Publications and reading
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those Publications we're supporting his laboratory you can do that by going to his laboratory website which we have
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also linked in the show note captions before we begin I'd like to emphasize that this podcast is separate from my
Sponsors: HVMN, Eight Sleep, Thesis, Momentous
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teaching and research roles at Stanford it is however part of my desire and effort to bring zero cost to Consumer
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information about science and science related tools to the general public in keeping with that theme I'd like to
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thank the sponsors of today's podcast our first sponsor is hvmn Ketone IQ hvmn
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Ketone IQ is a supplement that increases blood ketones I want to be clear that I
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am not following a ketogenic diet most people fall into this category they are not following a ketogenic diet they are
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omnivores and they do eat carbohydrates so their standard fuel source for the brain and body is not ketones however I
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found that by taking Ketone IQ which we know increases blood ketones I can achieve much better focus for longer
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going into that exercise fasted and find myself a little bit hungry when I start that exercise this is no surprise we
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in other words I and many other people are now starting to leverage endogenous ketones as a fuel source for the brain
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just mention that the library of those supplements is constantly expanding again that's livemomentous.com huberman
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and now for my discussion with Dr Sachin Panda Sachin Dr Panda so good to see you
Time-Restricted Eating (TRE), Calorie Restriction (CR) & Health
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again yeah good to see you we are colleagues still but we used to be right across the street from one another yeah
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yeah you remember those days yeah yeah so I'm delighted that you're here um I think we're going to talk about a
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number of things mainly intermittent fasting time restricted feeding and health but also the many
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other things that you're doing just before we started recording we were discussing your recent paper in nature
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uh that involved recordings from post-mortem Human retina so maybe if there's time at the end we can get back
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to uh your lab has shown that you can essentially maintain or resurrect
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neurons from uh dead people in order to potentially
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and eventually provide transplants to rescue Vision in the blind so that's extremely exciting but of course not the
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main focus of today's discussion so we'll have to uh split it up um the first question I have is how am I
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supposed to Define fasting and time restricted feeding in meaning when I go to sleep every night
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I'm not eating so in some sense everybody is doing time restricted feeding to some
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degree or another yeah at what point can we start thinking about a pattern of eating as time restricted feeding
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so-called intermittent fasting does it have to do with how regular one is about the start and stop times how do
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you think about defining intermittent fasting time restrictive feeding and
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maybe just to simplify the conversation is one term more correct than the other in terms of describing this incredible
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pattern of feeding well you know that intermittent fasting covers many types of fasting
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um so actually it started long time ago and it's embedded into the history of
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caloric restriction um almost 100 years ago people showed
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that if you reduce calorie intake in a rat then that rat can live for a long time
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and in those experiments the calories were reduced every single day and that led to the idea that if we cut
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down our calories by 20 percent say then we can potentially live longer by doing
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two things one is preventing is related disease or even if we follow fall sick
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maybe we can accelerate cure and keep the repair mechanism going so
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that we can live longer but it was very difficult to
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count calories every day and reduce maintain that um
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I must say that it's not that calorie restriction is impossible or we are not doing it in fact
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a lot of us we do um count calories in our subconscious mind means every time you took out it
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you took out we take out a soda bottle or something I'm looking at it okay or in 60 kilocalo or 30 kilocal or zero
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kilocal we are doing that so the point is it's it's we are doing subconsciously some kind of calorie
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counting but reducing calorie by Twenty thirty percent every single day is not
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possible for many people so then the idea came in mouse and rat experiment
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whether they can eat every other day um and in fact this every other day
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feeding um also led to very similar almost equivalent Health Improvement as
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continuous calorie restriction um so then the idea was well every other
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day is a little bit hard for humans but just imagine I would just get to eat only one day and then another day
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then the idea came well for humans can they eat less for one or two days in a
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week so that led to this pipe two diet where people can eat for five days and then
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two days they have to reduce calories so that's also intermittently people are fasting
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um then as you know Walter longer also came with this idea that periodic fasting maybe four or five days in every
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month or two months three months you can fast or reduce calorie and he also found many benefits of
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calorie restriction was there were those studies on humans many of the studies
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started it in mice but alternate day fasting five two and
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um Walters periodic fasting all of them have now been done in humans not for longevity of course because
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cannot do this for a long time but for weight maintenance for reducing some
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signs of aging or reversing those things have been done so all of them have been done in humans mostly healthy humans and
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in some cases people with pre-diabetes or some aspects of metabolic disease so
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that led to the idea that that all these forms of fasting in which
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the total caloric intake on any given day is reduced for one or more days in a
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week a month that became that umbrella term became intermittent fasting
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so if you look up the scientific literature most intermittent fasting involves
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intentionally reducing calories for at least one or two days in a week
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or um few days in a month so when we publish time restricted
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feeding um the initial Mouse experiments and even now most of the mouse experiments
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we want to test what is the impact of time restriction versus calorie restriction
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so in these experiments we don't reduce calorie on any day of mouse life so the
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mice is the same number of calories as the adlibitum FED mice but still they say health benefit so
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that's why we call it time restricted feeding but since it involves
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living without food for several hours for some people which is it can be very
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difficult the initial experiments was done they were done for eight hours of
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feeding and 16 hours of fasting that kind of became popular and so that
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that's why people use the same term as intermittent fasting and now if you say intermittent fasting and popular
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literature or popular media then people usually refer to time restricted eating so now coming back to
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how do you define time restricted fitting um so the way we have been trying to
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Define experimentally and also in literature is um
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trying to confine all your energy intake from
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solid and liquid food combined within a consistent window of 8 to 12 hours
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because that's something that doable of course people have done time restrictive trading with four hours six hours and
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some people even try to eat everything within two hours one meal a day um but the point is those are not
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feasible to maintain for very long time for a lot of people one question about the six hour versus
Mealtimes & Circadian Clock
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eight hour versus 12 hour feeding window is it important that the feeding window
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begin and end at the same time more or less yeah and if so how much flexibility
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is there so for instance I'm somebody that I am not terribly hungry in the morning
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I like to drink water usually some caffeine and electrolytes yeah in the
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period before my first meal and my first meal always lands sometime between 11 and 11 A.M and 12 noon there are
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exceptions yeah occasionally I'll have a breakfast a proper breakfast as it's called Uh I guess it would be improper
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if you're intermittent fasting for me um but typically 11 A.M or noon is when
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I first eat my last bite of food is typically around I don't know 39 PM
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that's what works for me yeah is that consistency affording me any benefit separate and let's just leave
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aside total caloric number macronutrients plant-based meat Etc but is there any benefit to shortening that
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feeding window that we are aware of or extending that feeding window or being
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even more rigid about the start and end of that feeding window yeah so the start of the fitting window
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um that's interesting because the concept of time history feeding when I
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describe animal studies it's feeding for humans it's eating so the concept actually came from the science of
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