Live Like a Girl with Dr. Mindy Pelz - Time & Light: Missing Pieces of a Healthy Lifestyle with Satchin Panda PhD

Episode Date: May 20, 2024

Satchidananda (Satchin) Panda, PhD discusses the impact of food timing on health, advocating for personalized eating windows and gradual changes to fasting routines. Dr. Panda and Dr. Mindy explore the relationship between fasting, metabolic health, and gut microbes, emphasizing the importance of lifestyle factors like sleep, exercise, and diverse gut microbiota for overall well-being. Dr. Panda shares tips on adjusting to different time zones to support metabolic health during travel, highlighting the holistic approach to health through healthy daily routines. To view full show notes, more information on our guests, resources mentioned in the episode, discount codes, transcripts, and more, visit https://drmindypelz.com/ep236 Satchidananda (Satchin) Panda, PhD is a Professor at the Salk Institute in California, where his research focuses on the circadian regulation of behavior, physiology, and metabolism in model organisms and in humans. Dr. Panda discovered a blue-light sensing cell type in the retina entrains our master circadian clock, affects mood, and regulates the production of the sleep hormone melatonin. Recently, he discovered that maintaining a daily feeding-fasting cycle – popularly known as time-restricted feeding (TRF) – can prevent and reverse metabolic diseases. Based on a feasibility study in humans, his lab is currently carrying out a smartphone-based study to assess the extent of circadian disruption among adults. Dr. Panda has received the Julie Martin Mid-Career Award in Aging Research, the Dana Foundation Award in Brain and Immune System Imaging, and was a Pew Scholar in the Biomedical Sciences   Check out our fasting membership at resetacademy.drmindypelz.com. Please note our medical disclaimer.

On this episode of the Resetter podcast, I bring you such an panda. If you are not familiar with him, he is the circadian rhythm expert and has been doing a tremendous amount of research on time restricted eating, aka intermittent fasting. And so this is a conversation, wow, that I have been wanting to bring to you all for a very a long time. If you're not familiar with Dr. Panda's work, I can tell you that not only is he a professor at the Salk Institute in California, but he has done multiple research studies on circadian rhythm and particularly how it relates to the time of food, the time of light, and the time of movement, which we talk a ton about in this conversation. He has written two books, both all around

the circadian rhythm. My favorite one personally is the circadian code. And he has a really interesting app you all can use and might find helpful called On Time Out, which is all of his research put together in one area. Now, let me tell you what you're going to hear in this conversation. So a lot of you have asked me over the years, when is the best timing of food? Like where should I put my eating window. And he's going to answer that for you. It's really cool. The way he explains it is profound. And right now, just so you know, there's a lot of discussion about like, shouldn't I eat when I first get up in the morning, especially we're hearing this a lot when it comes to protein that we're supposed to get up and eat protein right away. He's going to tell you, well, I'll give you a little

clue. He's going to tell you why eating immediately upon waking is not a great idea. So you're going hear that in this episode. I also wanted to bring him into the jet lag conversation because a lot of people are trying to overcome jet lag and figure out how to shorten jet lag. And so I wanted to know if you could manipulate the time of your food to the new time zone you were going to. Could it possibly minimize the amount of jet lag you have? And he answers that. Really cool. And then of course, course, we had to go into this study. So if many of you are still wrestling with the media blitz that happened about a month ago talking about 91% increase in cardiovascular health when you intermittent fast, this was an exact opposition of some of the research he's done on 168 fasting.

So I wanted his opinion on what appeared to be the complete opposite of what he's seen in his lab. And then we ended up on the weight loss drugs. And what does he think about the weight loss drugs and how that fits into circadian rhythm? And what do we need to know about the up and downside of the weight loss drugs? Really good in-depth conversation on all things circadian rhythm. So Dr. Suchin Panda, enjoy. I hope so many of your questions get answered in this as it did for me. And I just really deeply appreciated the way he brings the information forward.

So please enjoy, and I hope you get a ton out of this. Welcome to the Resetter podcast. This podcast is all about empowering you to believe in yourself again. If you have a passion for learning, if you're looking to be in control of your health and take your power back, this is the podcast for you. Let me start by welcoming you to the Resetter podcast. and, you know, there's a lot of reasons people can be a fan of yours, and I really have to say, I've been following your research, I've read your book, I've been listening to your circadian

thoughts on timing of food, and it's amazing to me how much there is to discuss when you just bring up what to eat and when to eat. It's like there's years of discussion there. And so here's where I'm going to start this is by asking you, what's more important, when to eat or what to eat, especially when we're looking at chronic disease and inflammation and weight loss. I think it's a tough question because it's almost asking you to choose between one out of your two kids. So I guess both are important. But at the same time, imagine that the good quality food is your best friend. and if that best friend shows up on time

when you are free, then that's good. But if the best friend shows up, knocks on your door every night at 1 o'clock in the morning, then that person may not be that person may not be your best friend. So the point is, timing can make good food junk.

So that's why... Wait, wait, say that again. Timing can make good food junk. Can it do the opposite? Can it make junk food good? So I won't say that it can make the junk food good, but what I can say is it can lessen the bad effect of junk food. It can lessen the bad effect of junk food because the timing, depending on what time you're eating relative to fasting, timing can turn on many defense mechanism in our body, including genes that detoxify bad things. bad things in junk food.

So that's why I said that timing can lessen the bad effect of junk food. Right, which doesn't give us a free pass for junk food. I just want to point that out. But it is an interesting, you know, a lot of the research that you've done I have poured myself into. And one of the conclusions I've come out of your research and really thought deeply about is if we have such poor quality food and the food industry is profiting from this poor quality food. There's no incentive for the food industry to change. So therefore, the best tool we can give people for, again, for weight loss and inflammation and metabolic health is, okay, just take that toxic food

and let's compress it into one eating window so that you have a longer period for your body to rest so that, like you said, the genes can turn on, but it can also heal from the toxicity of food. Am I thinking that through right? Yeah, that's true. I mean, one caveat, I must say from the beginning is most of the stuff that I'll be talking about, about genes, biochemistry, proteins, or detoxification, all of these are done in laboratory mouse models, because that's where we can actually go look deeply into all these factors. We can also give the mice healthy food or junk food at different time of the day.

And very systematically, methodically, we can look at every single gene in the mouse genome. And in fact, we share almost 99% of the genes with mouse. So that's why a lot of this can be translated to humans. In fact, every single medication, supplements, everything that we eat that we take to manage, prevent, or cure any disease were tested at some point in mice or many laboratory animals. So with that caveat, most of the biochemical stuff or genetic stuff that I'll talk about mostly comes from laboratory. You actually bring up a really valid point because in the world of science, I feel like a lot of times people will dismiss a good study because it was a mouse study. And they go say, well, this is a better study because it was a human study. And then

we have this new emerging question, which is, but the human studies aren't necessarily being done on the same demographic. Like, women aren't separated out. And like, I've read some intermittent fasting studies where they had a cohort that had 17-year-old men all the way up to 55-year-old women. and I'm like, you should never look at a metabolic system of a 17-year-old man and compare it to a 55-year-old woman. So just for the people listening, do you feel like we need more human studies? Or do you feel like the mouse studies really are giving us enough information of how to look at some of this behavior for ourselves? Well, the mouse studies give us some clue that it might work in humans. but we have to do these studies in humans

because ultimately we are doing all these research not to make mice healthier, they're already healthy, but to make humans healthier and live a long, productive life. So we do have to go back to humans and do these studies. By the same time, for example,

when I talk about time retreating or fasting or anything that we do in the lab and we say, what happens in the liver? And in that case, We're actually going and looking at liver biopsy samples in mice, which will be almost impossible to do in humans, particularly if you're not having fatty liver disease and if your liver is not a threat, nobody is going to give a, I won't give a piece of my liver for simple biopsy.

Yes, I wouldn't either. So that's why we have to keep that in context. Like when we're talking about what is the impact of certain things, medication or supplementary, or lifestyle on internal organs that are very difficult or are most impossible to sample. For example, we can also look at impact of time registry feeding or intermittent fasting on brain health. By looking at different parts of the brain,

there is no way we can do that study on humans. But these studies actually tell us, okay, is there enough changes that we see in laboratory studies to begin to ask this question in humans? because usually the rule of thumb is if it doesn't help a mouse, it's less likely that it will help a human. You know the way I always say it is animal studies get us in the ballpark, then we've got to decide what seat we're going to sit at. And so I'm a big fan event of one, figuring out how to take these studies like the ones you're doing and how do we make them applicable to our own life, which leads to. me to my next major question for you is there's a lot of different lengths of time restricted eating

or fasting that has been researched. Do you have a sense for metabolic health, again, for cleaning up our metabolic system, which is a huge problem right now, what length fast do you feel like does that the best? That's a very loaded question because. Yeah, I know. It's the one I get all the time. Let's put it this same way as you would take a medication. So, for example, if someone has diabetes or prediabetes and is prescribed a medication commonly prescribes a metformin. There is no single dose of metformin that should be applicable to everybody. Because if somebody is newly diagnosed pre-diabetic, maybe somebody should take 500 milligram of metformin.

and if someone already has diabetes, maybe higher dose. And if somebody has really severe diabetes, then maybe two or three medications. So we have to put that into context. So similarly, for someone who has metabolic disease, and what we think metabolic disease, you know, it's a very fuzzy term, but we can break it down to individual components. So typically, the three things that affect us, that we, really are concerned about blood glucose, blood cholesterol, lot pressure. And blood cholesterol, we can say blood lipids, cholesterol and total triglycerate. Then we can add, say, abdominal obesity,

because that predisposes us to many different diseases. So now let's think about obesity and high blood pressure, high blood cholesterol, high blood sugar. So depending on who has what, and how severe it is, then one can begin with certain amount of fasting. The other thing is, when we are predisposed or we develop certain metabolic disease, it develops because of our interaction between genes and our lifestyle. And many of us do have bad genes, and that's inescapable. But then in terms of lifestyle, we have developed our habit of eating certain things. We have preference for certain type of food, amount of food.

Yes. It's not that easy to just start fasting right away. So that's why when we do our studies in humans, the first thing we want to see is, well, does timing actually, is timing contributing, mistiming of food contributing your disease? or is it something else? Like somebody may be already eating religiously, regularly within 10 hours window,

but that person may already have metabolic disease or metabolic syndrome. So then there is not much room for improvement in that case, but paying attention to food quality and quantity might matter. Whereas if someone who is already eating at a window of, say, 14 hours,

I'm not saying that every day this person eats within 14 hours. Just imagine in the last two weeks, one is the earliest time you ate. And one is the last time, latest, how late did you eat? And that is six o'clock in the morning. Some I woke up and had a cup of coffee with cream and sugar and something else to munch. And then the last time I ate over the last two weeks was going out for dinner and having a very late dinner, say, at least a couple of times in the last two weeks, say, at 10 o'clock or 11 o'clock. So that gives me already 15, 16 hours of window within which my body was expecting food. So in that case, reducing that eating time to a narrow interval might benefit.

Because it's a change? Is that because you're switching it from what you're regularly doing? Yeah, because we habitually or randomly over the last two weeks, if I have it in two or three times before 8 a.m. in the morning, two or three times, after 8 p.m. in the evening. So that means my body is already used to expecting food between 7 a.m. to 9 p.m. Body has already gotten this signal that, okay, so this person is likely to eat within such a long winter of time. Yes. The body remembers it. So in that case, reducing that timing to a sort of time can be beneficial.

So then the question is, well, can I just go to six hours or two hours or three hours, which will be a huge shock and people may not be able to stick to it. So that's why we always suggest, well, if it is too difficult, try one week within sticking to a 12-hour window that works for you, depending on what time you wake up, what time you go to bed and what you do in the morning or evening. try to find a 12 hours that works for you. It's not saying that you should start skipping breakfast eating from noon to 8 o'clock, but select your own window.

And then if you get used to it for a week or two, then you can reduce it to 10 hours. Because both mouse studies and human studies that we do, we are seeing that when people who have a habitual or usual eating window 14 hours or longer. So that means over the last two weeks, you have eaten at least two or three meals within that 14 hours windows.

Suppose say 6am to 8 p.m. So that will give you 14 hours. Or 8 a.m. to 10 p.m. That will give you 14 hours or longer. Then reducing that to 10 hours seems to give many benefits. And so that's the starting point. You start with 12 hours

and then if you can reduce it 10 hours, then that's a good thing. And some people try to reduce even to eight hours or six hours. I must say that when we look at really objective data, because we have done this study on many hundreds of people now, and some people say that they can do eight hours, and they start. And after five or six weeks,

we see them drifting towards 10 hours. And then kind of stabilize. around 10 hours. So that's why we feel like 10 hours is a magic spot where you can have long-term compliance, long-term adherence. But if you can do eight hours, that's also good enough.

I think when people reduce it too much, and this is what we have seen in few cases, particularly with women, because women, I should not say this, but many women want to have it all. So they will start intermittent fasting or time-rish eating. They want to eat within, say, six to eight hours. They want to improve the quality of food.

So they end up eating only salad and they reduce their nutrient intake. And then they go on, they go for four miles, five miles run four times, five times a week. And then what happens is your body is actually into a shock because the body is not getting enough nutrient and of energy to sustain very basal metabolic processes that your body needs. And this usually happens mostly with normal wet people or slightly overweight people. We're trying to have it all.

And if women are still menstruating, then they would see irregular menstrual cycle or some of them can even become a menoric. And that's a good sign that you are getting into an energy deficit that's not supporting basal function in your body. That's why we

rarely ask people to reduce the eating window to less than eight hours because there is some risk unless you're paying attention to your quality and quantity of nutrition and physical activity along with it. That can be a respect.

So, sorry, that was a very long answer. Yeah, no, that was really well said and actually backs up a lot of my work. And what I've done with women specifically is make sure that we don't get at certain times of the menstrual cycle too much in this calorie deficit place. And specifically around the hormone progesterone doesn't do well when we're in too much of a glucose restricted state. And the thyroid doesn't do well with consistent calorie restriction. So I like for women to have a more cycling according to where their hormonal profile is and what's going on, whether they're menopausal or menstruating. And it leads me to this question for you is, do you feel like, so let's say I take, I go to 12 hours of an eating window, I get comfortable there.

Now I go to 10 hours. I'm like, hey, 10 hours is good. I think I'll just stay here. Do you find that the fasting benefits stop? If you are just super comfortable with 10 hours and you just do 10 hours over and over and over again, will you eventually plateau with results? Does the healing stop? What do we know about that?

Yeah, so there are very few long-term studies up to a year or more, so it's very difficult to say what are the benefits. But what we see is you've got to define what are the benefits. people experience. So when we ask people why they continue to do it, what is driving them to do it, then their usual response is actually not metabolic health to be as the immediate benefit. What they say is some of them, they say that they sleep better, particularly those who stop their eating window at least three hours before the habitual bedtime. So suppose if you're going to bed at 10 o'clock, if your kitchen closes at 6.30 or 7, then they tend to sleep better.

And then they experience that if they eat later at night, then that night they have bad sleep or they wake up in the middle of the night. So they tend to do it because they sleep better. The second benefit that we always hear is, I think that's linked to sleeping better, is they feel more energetic throughout the day. And, you know, if you're eating late and sleeping bad, then of course you'll feel lethargic the next day. So this is another benefit. And then the third one is a lot of people who have acid reflux or heartburn.

Either the severity of acid reflux or heartburn goes down or some of them who have mild form, it may disappear altogether. And these are the things. that actually tried people to stick with it. Then the question is, yes, the question is, well, suppose somebody was pre-diabetic, where the blood sugar level was,

fasting blood sugar level was between 100 to 145. They started doing intermittent fasting or time-resist eating, so within 10 hours, and they became normal glycemic. And then the question is, if they continue to do this, will they again become pre-diabetic?

Because that's when you'll say that, well, the benefits kind of disappear. And this is, I mean, personally, I haven't seen any case where people, and as I said, there are not too many studies where the studies have continued beyond one year. There is no theory study beyond one year. But what I hear anecdotally from people and also in my own family, one or two people who are pre-diverted, they became normal glycemic. The benefits continue for five, six, seven years now. And then the weird thing is once they start eating outside that window late into the night,

then yes, the hemoglobinase go off slightly. The fasting blood ducas go up and then they see that and then they come back reatt off to this 10 hours window, or eight hours window. Yes. And then they stay within the rinse. But the point is, as we get older, risk for many of the disease also goes up. So it'll be interesting to see after five, six, seven years or ten years, will you again become pre-diabetic or will your blood pressure

go off slightly? Because if there is a genetic condition, then the lifestyle eventually will show up. At the same time, you know, yeah, interesting. The point is, particularly the age between 35 and 60. That's when, of course, I don't want to say that 35 is middle-less, but it's pre-middle-less. Oh my gosh. You just made a few people turn off from the podcast.

No, no, I'm not saying turning off. But this period is very crucial for all of our lives because we want to be at our optimum physical, emotional, and intellectual health. Right? The physical health, we have to be metabolically healthy. We should be free of any disease for which we have to take a medication every single day. Let's make it very clear because this is the time when we have other things to do.

This is the time when people start a family or those who started a family earlier. This is the window in which the kids will get out of the house, they will go to college. And when you're talking about 50 to 60, maybe if you had kids earlier, you may even become a grandparent. This is also the time when there are a lot of life changes are happening. You may be changing jobs. You may be going for the personal life also. Some people may get out of a marriage, get into another relationship. This is also the time.

when people get into double or triple caregiving, the parents are aging, we have to give them care. The kids are not fully grown up yet. You have to care for them. And then if your spouse or your loved one has some other condition, you have to care for them. You have a lot of responsibilities at home, at work. You may be having some community engagement,

other stuff outside your friend, family relationship. Then your friends, say, full, so a lot of things go on during this age from 35 to 60. So that's why it's very critical to maintain optimum physical, emotional, and intellectual health. In those years. And once you maintain, once you glide to, say, fly to the age of 60 with great health, emotional, intellectual, and physical health, then the rest of the life, the next 30 years of 40 years will be much better. So that's why. Oh, amazing. I only have four more years to go. So you want to hit 60 in the best metabolic health possible. Is that what you're saying?

Yeah. Amazing. I always say that have a personal goal that, depending on how you look at it, if you have a children, then have a personal goal that you should be metabolically healthy without any chronic medication when your kids finish high school. kids finish college or when your kids are getting married so that you can actually dance, real dance, not this slow-moving dance for your kids. You sound like you're a dancer. Like I was asking somebody, why do you want to be healthy? And the person said that I want to really dance in my daughter's wedding.

Yeah. Oh, it's a good reason. That's a really good reason. That's what matters. So that's why coming back to the security. I like that. Then what happens is when you think about lifestyle, lifestyle breaks down to nine components. That is the quality, quantity, and timing of food, exercise, and sling.

And once we take care of this, at least if we take care of the timing component, then everything else falls into its right place. Because to be very clear, it's very difficult to remember. even keep track of how many kilo calories we eat in a day. I don't know about you. Nobody can sustain it. No, even I cannot guesstimate how many kilo-cales I have consumed. No.

So, yes. And the quality also, I cannot say how much carbohydrate, protein, or fat I consume on any given day. So the only thing I remember is the timing. So that's why timing becomes a very tangible, very, personal aspect of our life. And just imagine everything that we do in a day, even this conversation that we have between you and I, we set a time and we did it. And once we are on time, then everything flows perfectly fine. Just imagine if I was half an hour late to this podcast, you'd be so upset and mad, right? And throw everything off. It's a good analogy. It's a

really good analogy. Similarly, our body has the circadian timing. So that means it has a timetable that tells us that has already prescribed us, ideally when we should go to bed, how long we should be in bed, when we should wake up, when we should start eating, when we should stop eating, when is better for us to go outdoor and do some exercise and want to wind down. And if we are on that time. If we're on time with our body's circadian schedule, then everything will fall into its right bless. Amazing. So well said. So when we're looking at the timing of food, this has been a question my community has asked over and over again. When's the best time for me to eat? Is it, I always say, eat in the daylight. We have some new research that's coming out saying

you should have protein within a half an hour of waking up in the morning. We have other people say, you know, wait a couple of hours after you wake up. And yet I think a lot of fasters skip breakfast and have their eating window and like nine or ten o'clock at night. So can we, do we know from research where this eating window should go to maximize our metabolic health? Yeah. So this is a question that's always...

Oh, you've answered this a thousand times. No, no, no, it means it's a very personal, it all depends on your personal life. Because there are two things. One big thing is in the pursuit of perfection, we should not give up what is good for you. We always think about, okay, so there is, it has to be the super optimized perfect plan, but then it doesn't fit my schedule, so maybe I should give up everything. No, that's not true. So let's break it down to what time of the day, what happens in our performance?

already at different time of the day so that you can actually figure out when is the ideal time for you. So let's start with waking up. So when we wake up, that's the time when we have the maximum stress hormone, cortisol. So you may be saying that, okay, in the daytime, you are too stressed in the evening,

you're trying to juggle many things. You're stressed. We are doing wet lifting or strength training, whatever you're doing when it's stressed, but actually the maximum cortisol happens within 45 minutes after waking up.

Then the question is, well, we know that having food with cortisol is not a good idea because it doesn't... I was just going to say that's not a great comment. And then the other half of the story

is melatonin, which is the night hormone that rises throughout night reaches its peak maybe two to three hours before we wake up. and then it gradually goes down. And when we wake up, we still have nearly 30% of our peak melatonin level.

It has to go down completely for us to feel. And that's why some people, when they wake up a little bit earlier than when they're supposed to wake up, they feel like groggy, sleepy. And if you take a large dose of melatonin try to fall asleep next morning, you're feeling still sleepy because your body still has a lot of melancholy. Yes. Yes. So melatonin, in a reason to making your brain to sleep, it also makes your pancreas to sleep.

So that means when you eat your breakfast, most breakfast have some carbohydrate. That needs to be broken down to glucose and that needs to be absorbed by a body. So insulin plays a big role in that. But when melatonin is around, insulin products on pancreas are slowed down. It's not completely stark, but it's just slow stuff. So in that way, in the morning, as the stress hormone is high, and balatonin is high for at least an hour or two, it's not the right time to eat.

I think I started saying that one should wait for an hour or two after waking up and this has now amplified. Everybody's followed. But it makes sense because what you're saying is that when cortisol and melatonin are high, what you need to be metabolically healthy is not quite there. So it would make sense to wait for these two hormones to go down and then eat so that you're putting yourself in a little bit, a better metabolic advantage. But here is another caveat. That is there is no human study yet showing this effect. And the reason is, the reason is,

The reason is it's really, for that study, you have to actually bring people to the clinic. They should sleep there. And then immediately after waking up, you can start measuring melatonin and cortisol and also give them a bolus of food and measure their blood glucose for the next one and half hour. Which is a very difficult experiment. Got it. The converse has been done where people are given food because melatonin also rises two to three hours before. before we go to bed. So then the question is,

if you give a bonus of four very close to bedtime, measure melatonin and measure blood glucose, then there is a nice match between how high our melatonin is and how bad our body is. Our sleep, I've seen it on my

aura ring. I see it all the time if I eat too late. So that thing has been done. But the more, One, experimental, it has not been done. It's just based on the idea that this might have. But at least few in many of our studies, we have seen people who just delay their breakfast.

I'm not saying that they're delaying their breakfast to noon or 10 o'clock. They're delaying a couple of hours in the morning, but they're not actually advancing their dinner time that much because the delay itself is giving them 10 hours. they also improve their blood glucose level. So, you know, it's not too many people. We don't have enough power there to say conclusively, as I said,

there is no very specific human study in this subject and this topic that there should be a good morning fast of one to two hours. Right. The hormonal profiles make sense, and then there are some studies, few individuals who deliver fasts, they have benefit from their glucose profiles. so those things are like.

So then eating in the light would make sense. Like try to eat when it's light out. Daytime. So unless somebody wakes up at 2 o'clock in the morning and have virtually. Yeah, but that's not there. That's shift working, which I want to get to in a moment. Or, you know, even what happens when you change, like you go into another time zone.

One question I have in, I've, I've, I've done a. bunch of research on this is our microbes. How much are our microbes involved in this process of helping regulate blood sugar? And do the microbes have a circadian rhythm that we need to be following? We're talking about hormone patterns. What about those microbes? Do they have a circadian rhythm? As the microbes actually change throughout day and night. So, for example, we go to bed with his, set up microbes in our gut. and we wake up with a different set. So the composition of our microbiome

actually changes throughout 24 hours. The reason is very simple. When we fast, as we fast, our intestine has less food than the environment for those microbes changes. So this fasting environment from more certain microbes and suppress other microbes.

And then, as we eat and we have food in our system, that changes the environment. So again, they switch flips and certain type of microbes of florence and other microbes will die down or will reduce enough. So there started showing, yes,

the microbial composition changes throughout 24 hours. And we are, at least there is one thing that is universally now accepted from microbiome research researchers is we should have as many different types of microbes in our body as particularly beneficial microbes in our gut as possible because they do different things. They can break down food into different bioactive molecules and norrisus.

So then the question is, do you want all the actors on the stage at the same time or do you want the actors to come do their part a different chapter of the play? So by having a strong feeding fasting cycle, you essentially have a nice orchestra or nice play going on inside your gut so that at different times you have different microbes coming in doing their part when they can flourish and then they are disappearing, making room for the other set of microbes to come in and do their part. So I'm wondering then if we have different microbes at night compared to the day, then what would signal that could be the change of light, which then do those microbes maybe don't, you know, you've got the, I love the way you phrase that when melatonin goes up to put us asleep, the pancreas goes to sleep. But do we also have another effect of the microbes dramatically shifting? And those are not going to be as good at regulating blood sugar or absorbing nutrients. because they're meant to be a different set of microbes for nighttime? Yeah, so those things have not been investigated that well, at least in humans. In mice, we know that there are different sets of microbes. They come up at different time.

And again, there is not much research on what happens to that microbial composition if we shine light on the mice at different time of the night. But for the circadian system, as far as we know, so far, the light has to go through the eyes or the retina to reset the master clock in the brain, and then that brain clock has to send signal to the rest of the body to influence the kiddo them. So there is not direct effect of light on the microbes, independent of the brain. It has to go through the brain. So there is not much research on that.

And most of the microbiome microbiome changes largely connected to the quality quantity. and timing of food we eat. I said, again, largely connected. And since the quality, quantity of food also changes a different time because what we eat for breakfast is very different from what we eat for dinner, they are also nourishing different types of microbes at different time. So the microbes respond to the quality of food and when you eat, and now that you're going to get the rhythm of these microbes,

depending on your lifestyle behavior around those things. Yeah. Now, what happens if you change time zones? So this is something that I've been thinking about with jet lag in general. Can we use timing of food to either improve jet lag, you know, response to jet lag? And what happens when I go to a completely different time zone? How long does it take my microbes to really reboot themselves and get on to that new time zone? Yeah, so the studies showing initially we thought that all the resetting of our circadian rhythm to new time zone occurs primarily through light, which is still true to large extent, because light affects our sleep wake cycle and a timing of food affects directly affects our metabolic rhythm, which in turn influences sleep wake cycle.

So then the question is, how can we combine the effect of light and food? How do we optimize that when we travel to new time zone? Or, for example, when you're doing shift work, how do you adjust in different shifts? So this is, again, an active area of research, and at the same time, it's a very difficult area of research because, you know, you have to abruptly change light and darkness, either in laboratory, condition for mice or in humans and clinical studies, because it'll be even more expensive to fly people from here to Europe for your studies. Yeah, that's...

That would be tough. But still, the bottom line is, yes, by adjusting the foot timing, at least in animal models and rats, they do reset to the new time journey much better and much faster. So the rule of thumb is, we need at least one thing. to adjust to a one hour change in time zone. And some people may take even more than that. Just imagine when the daylight saving time and standard time, those things change.

Some people can take up to a week to readjust to the new timing, which is only an hour. Right. Just imagine that your body can take one week, after one week to adjust to one up. So in animal experiment, in rats, people have shown that when you, change foot timing in sync with light dark cycle,

than these rats reset their clock to the new time zone or light dark cycle much faster than the rats that just changed the light dark cycle and there was no chance to foot timing. They could eat one of the one. So that brings up this important question, like when you own, particularly when we start travel, on the travel day,

many of us we try to wake up very early in the morning because again, I just imagine the real life if you are traveling with somebody else

and you have to wake them off you have to take care of a few things in the morning. So you may be waking up one or two hours and sometimes even three hours before you're habitual wake of time to get to the airport

or start driving. And so that's a circadian rhythm disrupts on to begin with because you have reduced your sleep time. And then when you reach the new time, John, if you're reaching late at night, our reflexive behavior is, well, you should not go to bed, empty stomach, so you should eat something, and you're actually eating very late at night at the new place. So, and then in between, if you're flying across a continent, if we're going from here to Europe or vice versa, sometimes we entertain. ourselves with a lot of airline food in flight.

Oh, on the flight, right. And watch movies and stay awake. That again is a lot of disruption. So the bottom line is if we pay attention to what time you are eating, what time is your flight or when you are reaching. And if you try adjusting your time, timing of eating to the new time journal on the day of your travel. So for example, at least the day of your travel.

Because, you know, some people say that you should try adjusting two or three days before, and it's very difficult because you're trying, you're preparing to do stuff. And then if you're there only for two or three days and coming back, then that's not much time to adjust. If you cannot do two or three days before, then at least that day. So, for example, if I, when I fly from, say, west coast to east coast, I also go through the same thing. I have to wake up an hour or two earlier to get to the airport. and at 6 a.m. in the morning when I walk through the airport, it just screens when I see people lining up to get that morning breakfast, morning bagel. Oh, me too. Me too. And the line is long and the food is toxic. I have the same problem

when I look at that. It's like, come on, I'm not going to work. You can sit in there. A aeroplane, you're not running, you're not going for a 10K. Your body doesn't need that food. You can just go, take out your neck pillow, an eye mask, and try to catch up on that sleep that you lost. And that's what everybody who travels should try to do. And then in flight, and after you have rest,

it means from west coast to east coast is sometimes can be three to four, five hours flights, then you can take out whatever you have brought with you to eat or eat a little bit on flight and then when you reach, ideally you're reaching before nine or ten in the night so you can reach and have some food. So then the next day morning, and this is something that's very important, that next day morning, if you can go out for a morning walk, slow jog, or be outdoor after waking up, that actually helps tremendously to reset to the new time journey.

In fact, many successful people, I have met many successful businessmen and other professionals who travel a lot and have been healthy. I ask them, so what's your secret? They'll say, we tell you one thing. Never eat in flight. Yes, that's my secret.

I don't eat on the flights. And then when you get to the new place, if it is still daylight, go for a run. Or next day morning, go for a run. Next day morning, go for a walk if you cannot run. Because another thing about enjoying a new place is to go early morning, go for a walk. Typically within an hour after sunrise, because that's the time when the cities are completely empty. you feel like you own this place. You're the king or the queen.

Yes. You can take nice pictures without all the tourists there. Yeah. So then let me just recap what you just said because I think jet lag is really an interesting conversation because more people are traveling and it's just becoming like we used to drive cars. Now we hop on planes. So are you saying if I could a couple of days before going to a big time?

zone shift, if I could start to eat in accordance to what that time zone would be like, then that could help. It's one factor that could help with the transition into that jet lag. But it's not always ideal because, for example, if you're flying from West Coast to Europe, then that's a nine-hour time shifts. That means I have to wake up in the middle of the night. That's right. I'm doing that next week.

This is why I'm asking you. I'm doing that on this Friday. And I already, so I've already downloaded the app that tells me like how I should be going to bed a little different. And then I'm thinking, okay, well, now in light of this, I'm like, how do I maybe put the timing of food and look at what my eating will look like when I'm there and start eating in that pattern a couple of days before I go? I mean, if you're flying to Europe, then I usually don't eat and fly it because most of the flights are less than 10 hours. means from West Coast sometimes it's 11 hours, but then you take out one hour after take off and one hour before take off when you cannot sleep. So that leaves only 8, 7, 8, maximum 7 to 8 hours. And that's what you should be sleeping because you should get to catch up with your sleep.

And then to be fair, I mean, the breakfast in Europe is way much better than the food, the serve and flight. So we love some appetite, go have a good breakfast in Europe. Yes. Yes. Yeah, don't deprive yourself just to reset your circadian rhythm is what I heard in that one. So, yeah. So that's beautiful. Okay. So the next question I have to ask you, and I'm sure people have been asking you this recently, is, you know, so much of the research I've seen you talk about and you produce and bring out into the world has been about the metabolic benefits of intermittent fasting, not just from a hemoglobin A1C, but when we're looking at cholesterol and blood pressure and several metabolic markers. And then we have this headline is what I'm going to call it that came out like a month ago that said, if you intermittent fast, 91% increase in cardiovascular event. Can you talk a little bit about that? Because we were flooded with questions on that.

And when I looked at it, I thought this is an exact opposition of the research I've seen you produce. So it didn't really make sense to me. Can you address that so people understand what that headline was and was it accurate? And how does it tie into the research you've done? Yeah. So let's try to explain what was that research. So what happens in the U.S. almost every couple of years, there is this survey that goes out to thousands of people that randomly picked in a way that they represent all ethnicity or agents, etc. and one of the questions there is what did you eat yesterday and how much you ate?

Not typically when you eat it because, you know, the questionnaire is not actually optimized to accurately say when this person ate. But anyway, so they collect this information and then they also collect other information whether the person is smoker, non-smoker, all the other information, which is called Enhanceless, the sort form is done in every two years. And that helps people to kind of look at the broad picture of what is going on with respect to health, what percentage of these people who are interviewed were obese, what percentage are healthy, what problems they have, and all that stuff. That gives us a very good idea of what is the state of the health and the country. but it doesn't give us a good picture of what people eat

because more than 60% of people in those surveys they underreport what they eat because it's very difficult means if you ask me what I ate yesterday and all the person's size becomes very difficult to describe on top of that when I ate people who say yeah I had breakfast or 8 o'clock or maybe they forgot

and then people are not objectively asked when it was your fast calorie when was your breakfast So the survey is, there are a lot of studies saying that the survey is not the best way to collect nutrition information. And in fact, there is a Mayo Clinic article saying how more than 50% of people report metabolically implausible amount of food they eat. For example, a 100-klo person or report that you see had only 400-kilocal. That's impossible. So there is a lot of problem with that data.

So that's why that nutrition data has never been used to set policies about what and how much people should eat. To be very clear, that nutrition data is rarely used to do certain policy. Second, that nutrition data is also never used to say that whether you should eat this way to reduce the risk for other diseases. So essentially this is a garbage in, garbage out kind of analysis because the nutrition data collector is a very poor world. So now, in this study, what they reported was,

they asked people who were eating less than eight hours. This is very important that they asked, did they eat whatever the reported, was it less than eight hours? They didn't actually say whether they were eating only one meal. Some people say that we had only one meal. because maybe that day they ate one man or whether they or how much they ate there was no explicit in that abstract

there is nothing saying that how must they eat what they ate is just one thing that's they ate within less than eight hours and then they try to match what kind of people are dying every year then they try to match them to this survey which is very indirect way of connecting who are the people who are dying in the next five or six years

and then this is called the National Death Index and then connecting with it's not that those specific people were dying because those specific people are not longitudinally served. So it was a little bit difficult to make this connection. You have to do some statistical foot plus to make that connection. And another thing was this was not meant

for public consumption, this abstract, When we go to scientific meetings, we usually put a small study and then see what people think, people give us feedback. And then we come back to a lab and take, oh, maybe this is not a good idea. Maybe I have to do more. So that's the purpose of scientific conferences where we submit a very small article, less than 500 words, saying this is what we find. And then sometimes we do put a poster. So that means it's like two or three figures. Think of your high school science fair project,

how people put a poster is almost like that to get some feedback. And unfortunately, American Heart Association decided to put it for public consumption instead of scientific discretion. In addition to scientific discussion. And then when it came out, although it's not peer-reviewed by other scientists, to the same rigor as end. any journal article is peer review.

And there is no scientific discussion going on. And when it went out, people got really scared. People freaked out. We got calls from office and saying that, hey, I want to withdraw from this study because I might die. And we got, you know, there are regulators. They would actually say, well, now in light of this study, this finding, do you think that you should continue this study? and wow

there are many scientists who got these kind of questions from the patients and the medic physicians who got a lot of questions from the patients so that's why we had to come together and put a statement

and that statement is now circulating in social media we put it back to American Heart Association and then we decided that we'll put the statement out there because if you back and ask the same thing, since a lot of people are underreporting their calorie,

including the obese people, they actually underreport their calorie. So does it mean, if you take it along that line, that that would sound like if you eat less, you may likely become obese, which is also not true. It's not caused, yeah. So that's why, yeah. And then if you look at what, how many people, the headline is 20,000 people study says this or something. like that. Right. Yep. I looked at this size.

Less than 500 people actually reported that they were eating within eight hours or less than eight hours. And if you look at them, that disproportionately more likely to be smokers. And we know that smoking has a huge impact on heart disease and under many other compounds. And as they said, they never reported how many calories were they eating. And why were they eating for less than eight hours? no one, it means this study

actually collected data from many years ago at that time intermittent fasting or fasting was not a thing. So the question is why were they eating? So that also

brings up another issue that we have seen with respect to sleep. People say that once would sleep between six and half to seven and half hours. The reason is

there are many studies all over the world on millions of people now if we combine all the numbers showing that those people who habitually eat between six and a half to seven and a half hours have significantly reduced risk for many metabolic disease and morbidities. So then the question is, well, people who sleep less, of course, we always advise them to sleep a little bit more. Those who sleep four hours or five hours, we can tell them sleep more.

But then the question is who are habitually sleeping for eight hours, nine hours, because they feel like they have to rest that long. Professional athletes, for example, they need more than eight hours of seeing. So are we going to tell them, hey, your chance of dying is much higher because you are sleeping more? No, because the lifestyle, the body demands that long period of sleeping, so they should sleep. love. We should not ask them to reduce their slave. Ah, well said. Well said. Yes, that's a great analogy. What are your thoughts on the new weight loss drugs? Because one of the things that I keep hearing from a lot of people is that

they're just not hungry. So in some sense, they're fasting. And so, but then the dark side of that is sometimes they're not hungry at all and they're bringing in very little calories. Do you have, Do you have any opinion on where we're going to be heading with these weight loss drugs? And the purpose of them is to improve metabolic health. But we also know intermittent fasting improves metabolic health. So where do you see it fit into this conversation? I think the drugs are extremely useful because the reason why we need drug is what our lifestyle is recommended. some of us fail to follow that lifestyle.

So, for example, for many of us, as I said, through many, many years of eating habit, we essentially change our brain in a way that our brain just wants those food. It's very difficult for us to have control over our craving so we cannot stop. Or even if we know that this is not healthy, we just go and have that big portion size

because our brain doesn't get the signal that your stomach is full. So for them, it becomes very difficult to control the hours to heat. And in that way, in those cases, those who are BMI, say, 35 plus, and they have tried everything, and they're not losing weight,

they're still having comorbidities, then it's okay. to have this weight loss drug or type 2 diabetes drug because these drugs were essentially initially designed for managing type 2 diabetes. And they have been very effective. They can reduce hemoglobin A1C substantially. That is very difficult to achieve with metformin

or the first line of drugs. So then the question is, well, we know that there are many side effects, loss in appetite, so that also leads to loss in total energy and take loss in macronutrients and micronutrients. And that's spawning another industry of supplements and a very specific macronutrients, a protein impact. And I guess we'll see this going on for a while.

And I think the long-term studies or the long-term effect when it becomes more and more apparent than maybe people will think twice. example, there are studies showing that chronic use of this wet-lust drugs, I won't say wet-lust drugs, because they may be taking for something else for type 2 diabetes, the GLP-1 receptor agonist, it does reduce our peristysis motion and our gut. So gut doesn't move forward as much as it used to. Some people develop gastropyracis where you can say your gut goes through paralysis or something in extreme cases. So there is indigestion, vomiting, and all that stuff that can be chronic even after you stop the talk. Although the risk is still

pretty low, it's not negligible. So if there is a risk of developing this gastropyracies or this gastrogy effect, even one percent of people who have taken the drug for one year, and if you compound it over 10 years than maybe 10% or so, then you have to think twice to see, okay, so can you manage it slightly differently? So, for example, when I talk to many physicians, they say that they try to put somebody on the lowest possible dose for a while to see how they're reacting, and then they continue maybe escalate this depending on the target. So most of it is actually prescribed for type 2 diabetes.

They see the person is responding well and is stabilized. The appetite is coming back slowly than they continue. And now the second thought is, well, if they don't want to, if the patient doesn't want to stay on this drop, then can they begin with very low dose and intermittent fasting or time is eating, and will that help them to sustain the benefit of the drug without too much of the adverse side effect?

I must say that this is just a thought. Interesting. This is a hypothesis. I haven't seen any actual human study that has begun, but I hope somebody will start those kind of studies where the lowest possible doses, along with some form of intermittent fasting, timeless eating,

along with healthy nutrition advice, because we have to think about the macro and micronutrient balance. And I guess that will be, that kind of study will give us some idea. Okay, so is it good to combine these or there is no benefit? Yeah, what to stack it with. Yeah, yeah, beautiful, beautiful. Well, again, thank you for letting me pick

your brain. I'm a big fan of the research that you've been doing and the message you bring, I mean, you've changed a culture in not just time restricted eating, but also in all things light. And I love this idea of movement, like this timing has been, I feel like a part of the health equation that has not been talked about enough. And you've just been such a champion of it. So thank you for that. I have to, I have to finish up on my favorite. question to ask everybody, which is, what is health for you? Like, if you could define health, how would you define it? Because we're all chasing health, but often we're chasing something we don't know how to define. Yeah, so I always say that the best biomarker of good health is to have a good

circadian drug. So in the sense. Right, there you go. And how do you measure that? Yeah, so it's what you see every day. So, for example, when you wake up within, say, the few hours of waking up, you should have a good bowel moment because having a regular bowel movement is the best thing for your gut health. And I'm surprised to hear that so many young adults, particularly young women,

actually don't have regular bowel moment. And then the same thing with many older adults too. And then the second thing is, yes, after waking up and going outdoor, you should feel fully energetic, because the first half of the day is when we are really a lot. Our brain is a lot.

We can do more complex tasks. We can take an executive decision. So that's another feeling that you should have. I'm not saying that you have to wake up at 6 o'clock or 7 o'clock. Whatever your habitual wake-off time is, from wake-of-time plus 6 to 8 hours is your most productive hours of the day.

that in the late afternoon, you should not have too much muscle pain, joint pain, aches, and other stuff, because those actually limit our movement or musculoskeletal health, which is very important. And in the late afternoon, you should feel energetic to go out there, to have physical activity. And then you should also have healthy hunger in the morning, in the evening as you are winding down, you should naturally feel sleepy to go to bed. You should not be taking a sleep ed or sleeping pill to fall asleep. And to have this body's ability to sleep without any sleeping head and to be in bed to get some restorative continuous sleep for at least six hours.

I say at least six hours because as we get older, some of us have difficulty falling staying asleep for mortons continuously for six hours. So then this is my definition of health because once I was circadian rhythms I love that. They're going, then we know that everything else falls into it like this. Yeah. Amazing. Amazing.

Well, I love all your explanations and metaphors and analogies. And I just appreciate the work you're doing. So where can people find your book and, and you have an app? How do people find some of the really cool stuff that is available to them to interact with your work? Yeah, so I have two books now,

one of the circadian core that was published a few years ago, and now it has been translated in 19 or 20 different languages. That's quite satisfying, gratifying to see. And then the second book was mostly on diabetes because I realized that nearly half of the adults in the U.S. are pre-diivis.

or diabetic and once you get diabetes is a very nasty disease because once you get diabetes then it affects almost rest of our body and brain. So how you can prevent managed diabetes

type 2 diabetes, particularly with circadian optimization. That's the topic of the second book is circadian diabetes code. And then of course we do a lot of research which can be very

complicated for people to participate in. So that's why we synthesized all of that research around timing of food, sleep, light exposure, and exercise into a simple app

called on-time health. And it essentially tells people to be on-time with their own circadian clock. And that way they can... Amazing. And they don't have to do too many

counting calories or counting person size. I guess what I see is once we have a good control of our time, whether it is in your personal schedule or with your help, then you have a great sense of agency that you are in control.

And once you control the timing of food, then what we see, a lot of people, they feel that they are in control of the quality and quantity of their food. Similarly, Amazing. Once you set a time to go to the gym, you just have to go to gym.

You don't have to think about what you'll do. You just go to gym, and then you'll find things to do, and that will improve your cardiovascular health and strength training. So similarly, just keeping track of time is the first thing. I feel like the general theme of this podcast could be like time,

the missing piece to a healthy lifestyle. Like, it's so interesting to me, like how we talk about everything you're supposed to do, and we have left out of the equation the timing of all of that. So thank you for highlighting that. I think everybody's going to get a lot out of this. So appreciate you. And yeah, keep doing all the amazing work that you're doing.

Thank you so much. And have a perfect circadian day. I will. I definitely will. Thank you. Thank you so much for joining me in today's episode. I love bringing thoughtful discussions about all things health to you. If you enjoyed it, we'd love to know about it.

So please leave us a review, share it with your friends, and let me know what your biggest takeaway is.