Feel Better, Live More with Dr Rangan Chatterjee - #81 Why When We Eat May Be More Important Than What We Eat with Professor Satchin Panda

Episode Date: October 30, 2019

RE-RELEASE - This episode originally aired as a 2-part episode almost 18 months ago and has been one of the most popular episodes to date. After releasing Episode 77, I have had many requests for more information on the impact of circadian clocks on our health. I have therefore decided to re-release this conversation with world-leading expert in circadian biology, whose research in this area is truly ground-breaking. So, here it is! We know that snacking late at night isn’t a good idea, but until recently, there was little research into what health benefits we could gain from avoiding it. This week, I talk to world leading expert in circadian biology, Professor Satchin Panda, whose research has shown that mice who were restricted to eating within an 8-10 hour window were completely protected from obesity, type-2 diabetes, fatty liver disease, high cholesterol and cardiovascular disease! Professor Panda discusses the findings of his ground-breaking research and explains that when we eat really may be more important than what we eat. We delve into sleep, how research in this area may influence the timing that pharmaceutical drugs are given in the future, why we should wait an hour after waking before eating or drinking anything and much more. Professor Panda’s wealth of knowledge in this area is amazing and this is a really fascinating conversation. CAUTION: If you have diabetes or are on any blood sugar lowering medications, talk to a healthcare professional before you go for prolonged periods without eating. Show notes available at drchatterjee.com/81 Follow me on instagram.com/drchatterjee/ Follow me on facebook.com/DrChatterjee/ Follow me on twitter.com/drchatterjeeuk DISCLAIMER: The content in the podcast and on this webpage is not intended to constitute or be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or other qualified health care provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have heard on the podcast or on my website. Hosted on Acast. See acast.com/privacy for more information.

There are nearly 110 different disease conditions which may arise from circadian disruption. Or conversely, there are nearly more than 100 diseases where just taking care of your daily rhythms by paying attention to when people eat, when people sleep, how much they sleep, will substantially, significantly reduce the disease risk. too complicated. With this podcast, I aim to simplify it. I'm going to be having conversations with some of the most interesting and exciting people both within as well as outside the health space to hopefully inspire you as well as empower you with simple tips that you can put into practice immediately to transform the way that you feel. I believe that when we are healthier, we are happier because when we feel better, we live more.

Hello and welcome back to episode 81 of my Feel Better, Live More podcast. My name is Rangan Chastji and I am your host. Now, today's episode is all about our circadian rhythms and why when we eat may be more important than what we eat. Now this is actually a re-release of a previous two-part conversation way back on episodes 20 and 21 of this show which first came out almost 18 months ago. Many of you at that time significantly changed your behavior on the back of what you heard and I've decided to re-release this as one complete conversation for a number of reasons. Firstly, since episode 77 with Linda Geddes just a few weeks back on the importance of light for our health, many of you

have asked me for more information on our circadian rhythms. Now, given how much this podcast has grown over the past 12 months, most of you listening to it these days will not have heard this conversation previously. Secondly, many of you have actually asked me to re-release these previous two episodes as one complete conversation rather than having it split up into two. Even if you have heard this conversation before over one year ago now, I strongly suspect it will be worth revisiting as the information in it is simply incredible. Today's guest is the one and only Professor Sachin Panda. He's a scientist at the Salk Institute in California and is conducting research that is literally transforming the way people all over the world live.

His research is behind why many of our phones and screens dim down to an orange shade at night. He's also shown how different genes have a daily rhythm in the way that they function, but he's probably best known for his research in an area called time-restricted eating. The idea that when we eat may be as important as what we eat. There is so much amazing information in this episode. I really think you're going to enjoy it. And I think it is highly likely to make you think carefully and potentially question when exactly you are putting food inside your mouth. Now, before we get started, as always, I do need to give a quick shout out to some of the sponsors of today's show who are essential in order for me to continue

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shoes by going to vivobarefoot.com forward slash live more. Now, on to today's conversation. Sachin, thanks for joining me. Hi, Rangan. Very happy to be on your podcast. Sachin, thanks for joining me. Hi, I'm very happy to be on your podcast. Sachin, I think you are doing some of the most important work in terms of, you know, really hardcore research that is getting translated into real life clinical practice. I've, you know, I first came across your research probably about four years ago or so,

and I've been pretty obsessed with following it ever since, actually. So I was delighted that we got the opportunity to lecture together last September in Iceland. But, you know, I think there's so much we could talk about. But, you know, as I said in the introduction, you know, you are doing a lot of the research that is helping us understand what a circadian rhythm is and how important our body's daily rhythms are. I wonder if you could maybe explain to the people listening what exactly is a circadian rhythm. Yeah, circadian rhythms are daily cycles in sleep, work, eating, fasting, and even our ability to do exercise, physical activity, all of these rhythms that we experience on a daily basis. So the term circadian comes from a Latin word that means nearly 24 hours.

And the reason why we have these rhythms is these are controlled by circadian clocks are controlled by circadian clocks that are present in almost in every organ, in every cell, and in every brain parts of us. So having said that, if you lock me inside a room with sufficient access to food and a bed, but no clue about timing, then circadian clocks inside my body will produce these rhythms so that I will go to bed around nine o'clock every night, I'll wake up around the same time, say six or seven in the morning, and this will continue even though I have no access to timing cue. So that's the beauty of these circadian rhythms, that our body is pre-programmed to go through these daily cycles of sleeping and waking up. Our gut hormones in the morning and the digestive juice rise up in anticipation of food. In the middle of the day, our brain is at its peak performance so we can do

more complex tasks. In the afternoon, our muscles are more pre-programmed to do much better athletic performance. And almost every brain chemicals, every neurotransmitters, every hormone goes through these daily rhythms. So the most obvious circadian rhythm that we all experience is the daily sleep-wake cycle. But that's just the tip of the iceberg. And there are many other rhythms that go on inside our body. Yeah, wow. It's incredible that we've got these natural rhythms. And, you know, for me as a practicing clinician, seeing patients and looking at the research, it's interesting that a lot of the time, you know, we look at what's the best diet to eat, or we look at, you know, all kinds of things, you know, in terms of calorie consumption and all sorts of different things.

But for many years, we've never factored in time, you know, when are we eating these things? We've just factored what we're eating, not when we're eating. And I think that's what drew me to your research initially. And I think that's what drew me to your research initially. It was certainly some mice studies that I saw that you showed beautifully how when you restrict the eating window, a lot of different changes happen. I wonder if you could tell me how you even started to think about that and actually start to research this area. Yeah, so it started almost 20 years ago when the new technology to look at genes when they turn on and off became available. I became curious about what time of the day or night different genes in our liver, in

our brain turn on and off. And what we began to see was a very simple observation that many genes that are involved in absorbing nutrients, breaking them down, metabolizing them, and supplying nourishment to our body, they go through daily circadian rhythm. So that means at a certain time of the day or night, our body may be much better in handling a big meal or breaking down toxins than at the time of the day. But that was just an idea that came from looking at genes, but trying to test that in real life took another five to ten years. So the next thing we wanted to test is a very simple idea. If our liver liver if our gut is better primed to digest and use these nutrients

at certain time is it better if we align eating time to that time so to do that experiment we went back to a very simple experiment that has done almost 11 000 times in other labs. And that is, if you give mice some high-fat diet or high-fructose diet or high-sucrose diet, any diet that actually they like, they will eat it, and then within a few weeks, nine to ten weeks, these mice become obese, diabetic, they have cardiovascular disease, they have fatty liver disease,

and of course obesity. And a simple observation that we made and other people have also noticed is when we give mice this kind of diet, just like when we have yummy food, then we tend to eat, even though we are not hungry, and we might eat in the middle of the night. Similarly, mice also wake up from the middle of their sleep and they would eat that. And we know that when we sleep, our gut is not functioning well. It's not primed for digestion. A liver is not primed for digestion. So we did a simple experiment where we divided the mice to two groups, identical set of mice from the identical, from the same moms born in the same room, with the same microbiome. One group got to eat this high-fat, high-sucrose diet whenever they want, and the other group got the same unhealthy diet, but that was aligned to their circadian rhythm so they ate all that food within eight hours in the first experiment and then later in 10 to 11 hours and every week we measure the

food intake so these two groups of mice were eating the same number of calories from the same food but to our surprise the mice that ate within 8 to 10 hours were completely protected from all these diseases, obesity, type 2 diabetes, fatty liver disease, high cholesterol, and cardiovascular disease. Sachin, that's just incredible. Just to highlight that, you're saying that the mice had the same diet, the same amount of calories, simply the time that they had them was restricted. Yeah, exactly the same number of calories simply the time that they had them was restricted yeah exactly the same number of calories means we didn't even reduce the number of calories and we didn't even change the diet and we repeated this experiment three four times before i could really believe it because

this goes right against what we know in nutrition research for the last 150 years, that the amount of calories and the quality of calories matter. And for the first time, we realized that if you align your eating time with your circadian rhythm, when your liver, when your gut is primed to digest that food, it has this huge health benefit. prime to digest that food has this huge health benefit. And that was really surprising. And then the next step that we did was we said, well, we can prevent the disease. What if the mice already have the disease? So in the second set of experiments, we take mice which are already obese, diabetic, have disease have high cholesterol high fasting blood glucose and the only thing that we do is we don't change their diet

we restrict their diet to 10 hours sometimes even up to 12 hours works and this might surprisingly within few weeks they lose nearly 20% of their body weight, and the disease slowly disappears. This is, again, another huge surprise because there is no medication out there that works in mice that will take care of all this disease simultaneously within such a short period of time without any adverse side effect. So that's another question that came to us. What if these mice are eating within a short time and are fasting for such a long time? Are they physically fit? Can they actually do some of the complex tasks? So we put them on exercise treadmill.

So we put them on exercise treadmill. And again, the next surprise came. That is, these mice that were eating high-fat diet only for eight to nine hours, maximum 10 hours, they could outrun mice that were eating healthy diet but at random time of the day or night. So here is another example where the timing of food intake can optimize performance on an endurance test and now these mice just by controlling time they can outperform mice that are on healthy diet which is incredible then the third thing that we did was you know as we get older our neuromuscular junctions we, and then we don't have much motor coordination, and we are prone to falls. So we put these older mice that have gone through time-restricted eating, we call it time-restricted eating, and we put them on an accelerating rotor rod.

This is essentially balancing on a rotating drum. It's a very simple test for mice. And to our surprise, again, these mice actually stayed on the rotating drum for a very long time. And nowadays, almost any, we have gone back, repeated the experiment in many different strains of mice to make sure that this is not a strain effect. Both genders of mice, and we always find the same outcome. That is, if mice eat all their food within 8 to 10 hours, then they're completely prevented from all of this disease,

and it actually improves their physical performance, it improves their mental health, etc. It's just absolutely incredible you're right it absolutely flips what we have always known and what we've always been taught it just turns it on its on its head um i just want to clarify that when you say high fat diets because i know a lot of people listening will be thinking you know you know there's this you know lots of lots of things in the media about you know fat and carbs and all these kind of things when you say high fat is that the the chow that mice get high fat high sugar is that the diet you're talking about yeah so the high fat diet that we use in the lab

this diet is very similar to the western diet what people actually eat in western countries so that is on an average around 45 percent of fat calories from fat 20 percent calories come from sucrose or simple sugar and then 10 to 15 percent calories come from protein so that's the composition of this diet and sometimes we can even go up to 65% calories from fat. This is very different from what people consider ketogenic diet, not what scientists consider ketogenic diet. Because in mice, a ketogenic diet means the number of calories coming from fat should be 90% or higher. And that's a very difficult diet to even produce and maintain from ice

because 90% fat is almost liquid or pretty semi-solid, so it's very hard to handle. So there is a difference between this. When I say high-fat diet, it's usually somewhere between 45 to 65 percent of calories coming from fat and usually this diet also has 20 calories coming from sucrose okay so there's pretty reasonable amount of sugar there and is this refined and processed fats the reason i'm asking that is so i don't want people listening to get confused if they're having things like olive oil and avocados and olives.

We're not talking about that kind of fat, are we? No, this is very unhealthy. Unhealthy fats, unhealthy sugars. Yeah. Yeah. So, Sanjana, it's incredible. The benefits you've shown in mice is just phenomenal. That if you do nothing else and just change when you eat um you know you can

you can improve blood sugar you can improve your weight your fitness all kinds of things that people up and down the country in the uk but across the us and all over the world are looking to do everyone's looking for that simple solution but your research could have some quite profound public health implications. Yeah. I mean, when I looked at epidemiology of chronic disease and how it changed over the last century, if nutrition quality has a huge impact, then we would have seen that certain countries or certain cultures that eat more, say, carbohydrate diet, certain cultures that eat a high-fat diet, then they would have had a high proportion of this chronic metabolic disease, which is not true.

It means if you go back to, say, 100, 150 years ago, then epidemiology of chronic disease metabolic disease was not confined to certain culture and it was also rare even in many different cultures so the common denominator of all these cultures that are eating say high carb diet or high fat diet or any other different types of diet, was people had access to very little access to food at night because staying up at night under light was very expensive. Even in the middle of 19th century, it would take almost half a month of salary of an average income family in the UK to buy enough fuel to light up the home

for three to four hours in the evening. So people lose to it largely during daytime and very little food was consumed after evening. So that's why what we think is the one of the contributor, I won't say this is the only one, one of the contributors to rising epidemiology of obesity, diabetes, and chronic disease is our ability to have access to food 24-7. more than nutrition, it becomes a way we socialize, it's the way we even cope with stress, then eating at the wrong time can lead to disruption of the circadian rhythm, and that can lead to disease. I guess if we think about this on an evolutionary level, it would make sense, wouldn't it, that when it gets dark at night,

you know, thousands of years ago we wouldn't really have that ability to actually eat at that time you know it would be dark we'd be probably settling down to actually wind down for bed right yeah so uh so that's why even our circadian rhythm has programmed itself and our different organs to be in that rhythm. For example, starting from digestion, start from even chewing of food. As we chew our food in our mouth, we have saliva that begins the digestion process. And we now know that the saliva production itself has a circadian rhythm. So it slows down at night. So very fast type of saliva production slows down.

The second step is as the food hits the stomach, then the stomach produces various digestive juice, including stomach acid, and those things also begin to slow down at night. It's a little bit complicated because what happens in the evening, the stomach produces excessive acid. That might be an evolutionary program because since we are not likely to eat anything in the evening, if something goes into the stomach, it's likely to be pathogenic bacteria or something. And since our body would be sleeping, maybe this is a defensive mechanism to produce an excessive acid in the evening. likely to be pathogenic bacteria or something. And since our body would be sleeping, maybe this is a defensive mechanism to produce an excessive acid in the evening.

And then just like our brain sleeps, our intestine actually slows down. So intestine doesn't pump the food down the digestive tract at night. So the digestion process itself slows down the reason being throughout the day digestion and moving the food through our digestive tract causes a lot of damage to the lining stomach lining or intestinal lining and that has to be repaired almost one-tenth of our stomach lining is repaired and replaced every night. And just like you cannot repair a highway when the cars and trucks are moving, we cannot repair our gut if we eat at night. So that's the whole reason why the circadian clock in gut slows down food passes so that it can repair the gut lining.

So now you can see, starting from the process of chewing the food to getting the food inside our stomach to pumping it through the digestive tract, has a strong circadian rhythm, and that's why eating at nighttime also causes various gut problem gut inflammation and that might ultimately lead to developing allergies to some of the foods that we eat yeah i mean this is just so incredible to it really sort of resonates with someone who like myself who's been seeing patients so many years now that a lot of the problems you talk about, even, you know, digestive problems at night, heartburn, difficulty digesting food when they eat late, it all starts to make sense when you look at it through the lens of your research in the Sagadian clock, because, you know, the stomach acid going up in the evening, that's incredible.

And yes, I love that evolutionary explanation that actually we wouldn't be eating then. So if something's coming through our mouth, then it's probably not good for us. And we need to have a defence against it. And I'm finding the more, you know, as I get more and more experience as a clinician, I think about evolution a lot more and I think about, well, what purpose would this have served? Why is this displaying now and it never displayed itself in the past? How would that have helped us in the past? When we think about our stress response, that's a classic example of how a stress response worked very well for us when we were being attacked by a tiger. But if we're being attacked by emails and

to-do lists and workloads, it has very different response so so yeah it's it's super interesting sachin you know when we think about the skating clock you know what are the factors in our lifestyle that have the most influence on it yeah so the biggest factor is light. And if you think about it, almost all life forms on our planet have evolved and have adapted to this planet under a very predictable light-dark cycle. You might think, well, the weather is very different on different days. Sometimes it's sunny, sometimes it's rainy, sometimes it might snow. But almost every day there is one thing that is absolutely going to happen. The sun will rise up, even if it's cloudy, there will be enough light outside. And sun will go down in the evening and there will be darkness. So that's why almost in every living organism on this planet,

the circadian clock predicts and also responds to light. So that means that in different seasons, as the sunrise time changes, the circadian clock also has to adjust to this changing sunrise time. But in modern society, after the invention of electric lighting and with light available throughout 24 hours, a brain clock gets confused. So that's the first thing that happens. After evening, of course, the brain clock will anticipate maybe one or two hours of twilight time. But then beyond when it sees light then it gets confused it thinks night hasn't happened and so there is sleep disruption so we reduce our sleep and as we know

now from sleep research a sleep deprived brain cannot make right right decision. And when we think about decisions, we always think about making a decision about say, jobs or whether going out, whether to buy this, buy that. But we make hundreds of decisions throughout our day about what to eat, how

much to eat, and when to eat, what combination of food to eat. So the sleep-deprived brain again makes two to eat and when to eat what combination of food to eat so this sleep deprived brain again makes two errors in deciding about food one is when our brain is sleep deprived evolutionarily at night time we are supposed to get sleep and when we woke up when we got up from our sleep it was mostly in response to a danger so a sleep deprived brain always thinks that there is a danger and to cope with the danger it tells our appetite brain tend to eat more when we have less sleep, when we go to bed late at night. Second thing that happens is we also make bad decision about food. We don't reach

out for healthy food, healthy snacks at night. A brain actually needs energy-dense diet, snacks, and those kind of stuff. So then it kind of goes into a spiral because once we eat late at night, then the clock in our gut and liver, they get confused. They think whether it's breakfast time or lunch time, so they have to drop the repair and rejuvenation process that has to happen every night. Instead of doing that, they go back to digesting food and trying to push this food down the digestive tract so as you can see um so light is the primary disruptor of circadian rhythm and then it confuses the brain then we tend to eat late at night which is under our control this is where we where we can stop the disruption going into a spiral.

And then that triggers our peripheral clocks in liver and gut to think that this is not night yet, and it stops the repair process. Yeah. I mean, it's just so incredible. You see one bad decision, or maybe not bad. Well, we're in the context of health. We'd have to say one bad decision leads to another bad decision, leads to another one. And then you're in this vicious cycle where people struggle to make behavior change. And it's fascinating. I sort of listened to the podcast. No, I wrote a book

called The Four Pillar Plan, where I talk about these four core components of health that we've got the most control over. So food, sleep, stress, exercise, but I did sort of caveat that in the book where I sort of spoke about your research and how much of a factor that time is, and when we do these things is very important as well. But it's just interesting to me that those four pillars that I talk about are all affected when we are out of sync with our body clock. So, you know, eating late, for example, that will affect your sleep. You sleep worse. You don't crave fruit and vegetables the morning after you've slept. You crave sugary food. You feel tired. You don't want to exercise, but also your stress hormones are up the night after you haven't slept so in fact i'd go as far as saying and i wonder what you think about

this not living in harmony with your circadian rhythm in some ways would be a stress right yeah there's a big stress and that's what we also see. The stress response means hormonally, all the stress hormones do go up when circadian rhythm is not in sync. So I think the bigger question is this, that we are going to live in this society where we'll have access to light and food throughout 24 hours. And having some awareness about circadian rhythm will actually help us to make some simple decisions about say when to turn down our light when to prepare ourselves to go to bed and when to close the kitchen so that we can bring these rhythms back into our life

so i really love your four pillar plan because that helps us to that that's a nice framework to connect basic science research to translation yeah it's i'm you know i'm familiar with your research i'm always blown away when i read it but just talking to you it's just incredible hearing all these various factors in terms of how you know we've got all these multiple clocks it's not just that you know the sleep weight cycle is that our guts got the same body clock our eyes uh you know our liver you know i thought there was a study a couple of years ago which came out suggesting that um the time that we give our drugs to our patients the pharmaceutical drugs may have to change depending on what

organ they're planning to target. Are you familiar with that? Yeah, so that's a very emerging area in circadian rhythm research. Recently, we just completed a study where we find that nearly 80% of our genes rise up and then fall down or have a circadian rhythm in different parts of the organ. So when you think of 80% of genes are circadian, that also implies that nearly 80% of the drugs that target different genes should have a peak time for performance and also a peak time for adverse effect. And this is an idea that has been floating around for a very long time,

starting from actually late 70s, because people noticed that what time of the day cancer patients got the cancer drug or the chemotherapy had a huge impact on their prognosis, whether they get cured quickly or they took long time. And starting from then, there has been a lot of research in cancer field particularly because now we know that almost every organ, circadian clock, does one thing in common, that is to repair DNA damage and to reduce redox stress. So almost every cell, as it functions, it produces a little bit of what we call reactive oxygen species or internal toxin of the cell. It's almost like the garbage of any house that needs to be taken out. And during this process, DNA also gets damaged, and that has to be repaired. And most of the cancer drugs are directed against damaged DNA

or affect some aspects of this toxin production or DNA damage. So that was the earliest clue. some aspects of this toxin production or DNA damage. So that was the earliest clue. But as we learn more and more about circadian rhythm, we now know that almost every process involved in inflammation, nutrient metabolism, various hormone functions are also circadian. So now we know, for example, arthritis pain that affects a very large proportion of older individuals. The pain is more severe in the morning. We have more joint pains in the morning. The joints have swollen up. But what is surprising is taking the medication in the morning

doesn't help that much. In fact, taking the medication in the night before, just before going to bed, seems to have much better effect to reduce morning pain. To take it one step further, we realize that, and most doctors know, that our cortisol levels begin to rise at nighttime and reaches its peak level in the morning. And cortisol levels, high cortisol level, helps us to fight some of the pain. So the second generation of these drugs are slow-release formulations that a patient can take at bedtime, but the drug will begin to get into the bloodstream around midnight or later. And those drugs have even much better efficacy than taking the drug that start to get into the bloodstream in the evening. So these are some of the very early examples that timing the drug has a huge impact in reducing

adverse side effect and improving efficacy. And I suspect from what you were saying, Sachin, we'll probably in maybe 10, certainly 20 years, I imagine we'll look back and think, we said patients could take the drugs at any time. I imagine we'll have a time where we think, no, of course, if you're taking this drug, you take it at this time. You're taking this drug, you take it at that time.

Yeah. So that's where medicine might go in future and we think uh some of the chronic diseases that are going to that are affecting more than 10 percent of the patient population 10 percent of the adult population where we'll see huge impact for example blood pressure medication we know our blood pressure has a natural circadian rhythm. It should go down when we sleep. So blood pressure lowering drugs taken at bedtime will do two benefits. One is it will help to reduce blood pressure, but at the same time, it will also help to bring back the natural rhythm in blood pressure and that should happen so this is these are some of the very simple examples and as we learn more and more about how medications work for example the next generation of diabetes medications that are

coming to market at this sglt2 inhibitors and what is interesting is there are some small studies done to see the efficacy of this sglt2 inhibitors taken in the morning or the evening and at low dose it seems to be more effective in the evening than in the morning so these are some of the low hanging fruits and what i'm really excited about is the technology that's also coming on board. So just like we have insulin pumps for type 1 diabetics that are in a closed-loop system, they measure the blood glucose level and infuse insulin. Just imagine if we have the same kind of drug pumps that will infuse the right drug in the right dose at the right time even in the middle of our sleep then we don't have to depend on patients memory of when they should take the drug yeah just incredible so actually we could we could go down lots of deep rabbit holes here i'm sure

um one thing i do want to cover and probably we'll bring this bring it back to here for the for the remainder of the interview if i can, is you mentioned some of your time-restricted feeding studies in mice, so in animal studies. How are you getting on with actually translating this to humans? Yeah, so initially when we published those studies, there were many people who were skeptical for a couple of reasons. There are many people who were skeptical for a couple of reasons. Some people think that most humans eat all of our food within 10 to 12 hours in three or four meals.

So it may not have significance to human population. So to address that question, we started asking this in a different way. We asked, when do people actually eat? And what is the definition of food? Surprisingly, we don't know what is, we haven't defined what is a meal. So is, say, eating a banana considered a meal? Or having half a can of fruit juice? Or a cup of coffee or tea with milk and sugar is that food. So to address this, we came up with a very simple solution. We developed an app called MyCickadianClock that anyone anywhere in the world can actually go to this website,

mysickadianclock.org, and fill out a few questions to comply with ethics committee and the way we do medical research and then can download the app and snap a picture of what they're eating or drinking and we do the rest and from this research what we're finding is nearly 50 percent of adults in western countries eat for 15 hours or longer so that means if the first cup of tea with milk and sugar happens at six o'clock in the morning then the last sip of wine or last sip of milk might happen at nine o'clock at night or later and why this is important for us is when we put mice on a 15-hour diet, they eat everything within 15 hours,

we see that they slowly become more prone to metabolic disease. They'll slowly become obese and diabetic. So through this app now, we have more granular insight into when people eat. And it's not only a problem in the Western countries. We also find a similar trend in countries like India, China, Singapore, et cetera, where we find people actually spread their calories over a very long period of time throughout the day, sometimes 15, 16, even 18 hours. The second thing that we did is we asked, is it a modifiable behavior? And that's extremely important

because, for example, if we come up and say, eating only fruits is good for you, can people change all their diet to fruits? May not be possible. So we wanted to see if we ask people, try to eat everything within 10 hours window. Can they do it? And if they do it, then what happens?

So through the app, again, we provide them educational material and health tips so that they know why they are doing certain things, why they are trying to change, why changing their eating pattern and eating everything within 10 hours is good for them. And when we did that, what we find is people, of course, the first set of experiments is always done on not extremely unhealthy people, but moderately unhealthy people who have maybe slight increase in weight, overweight people, not extreme obesity. What we found surprisingly was, yes, it's a modifiable behavior people found it

relatively easier to adapt because they were not going to buy new diet they didn't have to carry a pen and paper or an app to count how many calories they are eating they just had to remember what time was their first meal and then count 10 hours and try to eat everything within that 10 hours. And they try to eat the same, maintain the same 10 hours window every day. And after 16 weeks, what we found is these people lost a good amount of weight, four to 5% of body weight. And then in the next year or so, when we didn't have any contact with these people, we wanted to see whether they can maintain that habit. And surprisingly, they did maintain that habit. They maintained their weight loss. At the same time, the third surprise came

when we asked them, why did you stick to this diet pattern? Was it weight loss? And the reason was no, it was not weight loss. The reason was no it was not weight loss the reason was they felt more energetic throughout the day they slept much better and they didn't have much acid reflux or heartburn and then we realized on a daily basis what actually affects us what bothers us is a good night of sleep feeling more energetic throughout the day, and not having that heartburn, having that stomach pain, stomach being uncomfortable with your gut at night. So we have taken it now one step further. Now we have a large study where we have thousands of people, tens of thousands of people from

all over the world. They're sharing their data, and we are learning a lot about what kind of other diseases this time-restricted eating of 10 hours will help. And we find some people can even go down to 8 hours, and some over around 11 to 12 hours. But any interval from 8 to 12 hours is good enough if people can stick to it. And we're finding benefits from metabolic disease to even in some cases, some inflammatory disease. Wow. I mean, Sachin, that's, you know, if I can just sort of relay what I find in practice, and I've probably been utilizing time-restricted feeding with my patients,

I'm going to say for at least three years now, I think. I think since I read, I think one of your 2014 papers, I think it made a lot of sense to me. And I also felt that intuitively it sort of makes sense that we're not designed to eat from 6am to 10.30pm. That makes sense. And I also felt that I can't really see any downside to this intervention. So I felt very comfortable recommending it. And I've seen some incredible results. The first thing I find is that compliance is really good. I mean, for patients who are really struggling with a lot of different problems, I often start with just 12 hours. I say, guys, can you just restrict, just keep eating what you're eating? Yes, I do try and

change their diet, of course. But I say, guys, just focus not so much on what you're eating, but when you're eating. And I think 12 hours, for example, which would be, let's say, breakfast at seven, finishing dinner by seven o'clock or eight till eight, I find most of my patients can do it. And even when I restrict it down to 10 hours, I think most of them actually can do it. But it's really interesting. You'll see that the compliance is there, which is just incredible. But also, I've also seen this when people do that, they come back and say, you know what, I'm sleeping better. You know, I've got more energy. And one thing I've learned in many years as a doctor is that, you know, patients aren't going to do what you ask them to do just because you tell them to do it for more than a few weeks,

you know, maybe a month, right? They're only going to continue by and large, you know, making a very broad statement when they start to feel better. And they go, yeah, I'm going to continue by and large you know making a very broad statement when they start to feel better and they go yeah i'm going to keep going with that and i'm probably the same as a human being you know so that's why i think this is such a powerful intervention because people generally feel better pretty quickly yeah absolutely and then also it's very intuitive and it is in alignment with many of the recommendations that doctors already make. For example, most physicians and most researchers agree that one should set aside eight hours in bed. If you are in bed for eight hours, at least you will sleep well for seven, seven and a half hours.

So, of course, those eight hours you're not going to eat. It's also a common sense not to eat within two hours before going to bed, at least. Because many people know that if they have a big meal, they go to bed, they cannot sleep well. So now you add that eight plus two or three hours before going to bed, you're already 11 hours, used to not be eating. And then as soon as we wake up, of course, give yourself one hour to do your usual stuff and then prepare some good healthy breakfast. So in that way, it's very easy to achieve a 12 hours eating

or 12 hours fasting window. And then the reason why we ask people to try to target 10 hours is if they try 10 hours, then maybe they will end up in 11 or 12. The doctors, the Christian secrets of how to actually engage your patients to do what you'd actually ideally like them to do. what you'd actually ideally like them to do. Kees, actually, I'm sure people will be listening there and saying, you know, I've got listeners all over the world, but a huge part of the listenership is in the UK.

Can they also access this app and put their data in to help you collect your research? Yes. Actually, now our ethics committee has approved us to capture data from anywhere in the world, as long as they have a smartphone that runs on Apple iOS or Android device and has a camera option, so then they can share their data. And I must emphasize that there are a lot of diet apps out there, but a lot of them capture the data, of course, for commercial purpose.

But here, all the data that we capture is de-identified, anonymized, and is put in HIPAA-compliant server with the latest privacy rules. And we don't share the data with any outside entity. I'm just going to highlight that for people who don't know the Salk Institute, it's where Sachin does his research. It is one of the most prestigious and well-known research

institutes arguably in the world, very, very reputable. arguably in the world very very reputable just taking a quick break in today's conversation to give a shout out to the sponsors of today's show athletic greens continue their support of my podcast to be really clear i absolutely prefer that people get all of their nutrition from foods but for some of us this is not always Athletic Greens is one of the most nutrient-dense whole food supplements that I've come across and contains vitamins, minerals, prebiotics and digestive enzymes. So if you are looking to take something each morning

as an insurance policy to make sure that you are meeting your nutritional needs, I can highly recommend it. For listeners of this podcast, if you go to athleticgreens.com forward slash live more you will be able to access a special offer where you get a free travel pack box containing 20 servings of athletic greens which is worth around 70 pounds with your first order you can check it out at athleticgreens.com forward slash live more no i mean this is the way where the modern clinical studies should go, because what we realized is another thing, that most of the clinical control clinical studies are done in maybe 20 or 30 or maybe 50 very reputable clinical centers throughout the world.

And all these studies are done on people who live within 20 to 30 or maybe maximum 50 kilometers from the clinical center so then what you practice as physician or what we usually tell people is based on a very small number of people who live within very small very close distance from these clinical centers and if you think about if you think about it we know certainly in the uk you know we know that socioeconomic groups change depending on where you are, for example. So in some cities, for example, it's right in the center of the city, it's lower socioeconomic groups. And as people go out to the suburbs, it's more affluent socioeconomic, more affluent areas. And so that will obviously skew which population you're pulling in that's yeah

that's super interesting yeah so that's one reason we thought in this way we can actually get very representative samples and we will know what kind of challenges people have in their work so for example nearly nearly all clinical studies exclude people who do shift work. Whereas now we can collect data from people who do day and night shift, 24-hour shift, emergency workers, and we can see what kind of challenges they have in adapting, say, 10 hours time restricted eating or 12 hours and what they can do. The second thing why I'm very excited about this way of doing research is when I go to do a research, do a study in my mouse room, I cannot ask the mouse, how is he feeling?

Whereas humans, they give us feedback. For example, this idea that time-restricted eating improves sleep. feedback. For example, this idea that time-restricted eating improves sleep. We have done maybe dozens of mice. We have put dozens of mice in time-restricted eating, but they never told us that they were sleeping better. It's only the humans who came back and told us. And then now we are going back and asking, why is that happening? Similarly, acid reflux, we never thought because mice also don't tell us. So this is another reason why when somebody downloads the app and then finds some benefits after time-restricted eating, and in the app there is a feedback feature, they can just write a sentence saying, well, I have this condition and this is helping me.

Then we take that information and come back, go back and see what is the scientific basis. And this gives us new ideas, new hypotheses to go back and do basic science research. That is incredible. So you're learning from the feedback and that feedback, you're now going back into the lab to try and figure out why that might have happened, which actually, if you think about it, that's what any good clinician or researcher should really do as well if you think about it you know i've i remember as a maybe five ten years ago as a as a doctor hearing stories from patients that oh when i do this i get better and i think well that's

interesting i've not really learned about that and you keep hearing the story you go that's interesting i want to find out why that intervention is working for those patients rather than saying oh it's oh that's rubbish you shouldn't be doing that it's like well you're telling me that's working i now need to figure out why is that working so i can see why the app would be so beneficial now that's the most fascinating part of uh doing this uh research this way we are learning a lot of stuff. So actually, that prompted me to go back and ask, because we found people with various conditions. For example, people who had depression, bipolar disorders, or anxiety, even night eating syndrome, arrhythmia, cardiac arrhythmia,

they all came back. And we would hear one or two stories like this, and then this is kind of the background noise level. And then when we hear the same thing happening in half a dozen or a dozen different people, then we go back. And the first thing we do is we read the literature. Is it reported that people who do chronic shift work, are they predisposed to this kind of disease?

Or is there an animal model where if you put the animals in disturbed condition, does it happen? Or animals or humans who have a mutation in circadian rhythm gene, does it happen? So when you put this together, what we're finding is there are nearly 110 different disease conditions which may arise from circadian disruption. disease conditions which may arise from circadian disruption or conversely there are nearly more than 100 diseases where just taking care of your daily rhythms by paying attention to when people eat or when people sleep how much they sleep will substantially significantly reduce the disease risk and disease burden. Let's sort of dive into that if we can. You're basically saying that many of the diseases that are now afflicting people,

the complaints, are in some way reflected to their circadian rhythm, or whether they're living in harmony with that or not. So what are some of those things? Are people listening going to go, yeah, that's okay, great. What can I do? So you're saying a time which sits at a window do we know if it's better to eat early and finish early or um you know eat breakfast late and finish late i mean i certainly know what i think on that but i just wonder

do you do we know yet uh which is better yeah so it's it all goes back to people's lifestyle so for example some people they go to bed very late because of the work or because of the family issues they have. And then they also wake up very late in the morning, say 8 or 9 o'clock in the morning. And for them, we cannot come back with a simple universal rule that one should eat breakfast at 6 a.m. or 7 a.m. So what I feel is maybe after you wake up, give yourself at least an hour before you have your first cup of tea or coffee or breakfast. That is also another reason why that is important is as we wake up, sometimes we wake up to an alarm clock.

So although our body, our brain wakes up, many of our hormones that keep us asleep, they haven't gone back to the state where we should be awake. Very simple example is melatonin. Melatonin levels rise throughout the night and that helps us to stay in sleep. and when we wake up in response to an alarm clock we wake up but then the melatonin hormone doesn't listen to that alarm clock it is still high and it takes another hour or so to come back to baseline to low level and when we eat that first bite when the melatonin level is pretty high, then just like melatonin makes our brain to sleep, it also makes our pancreas to sleep.

So that means in response to that breakfast, our body may not produce enough insulin to take care of it, to process that food. So wait an hour before having anything is one sort of take-home tip for people. Wait at least an hour. And some people, they don't feel hungry. They might have had a big meal last night. So at least one hour is a good rule. And then you can start counting your 10-hour window. So if somebody is waking up at 8 o'clock and having breakfast at 9 o'clock, then 10 hours will bring him or her to 7pm

at night in the evening for last bite and the reason why we say 10 hours is a good target is sometimes things happen it may be delayed it may be stuck in traffic or you may have to come home and prepare food so even if you go to 11 hours you are not booted off this island of time-restricted feeding but you but i think you said earlier on that really anywhere between 8 and 12 hours we know you're going to get a lot of the benefits yeah so uh there is there are some differences that we find in mice of course we haven't done the experiments um as rigorously in humans so what we find is when mice eat between eight to 10 hours, within that eight to 10 hours window, then they have a tremendous benefit on their endurance. So the muscle function

is much better. They can outrun mice that eat healthy diet anytime they will stay on a treadmill for more than two hours but if they eat somewhere between 11 to 12 hours then all the other health benefits are there but they it slightly reduces their endurance benefit and we don't know we don't understand why so now they will stay on the treadmill maybe an hour, hour and a half. And why this is important is as we get older, our muscle performance weakens, but at the same time, our heart is also full of muscle. So our cardiac arrhythmia slightly goes up as we age. So what we found in mice and also in Drosophila fruit flies is when they have a shorter time interval, then that cardiac arrhythmia is reduced and they can have high endurance.

So some people who want to improve their cardiac performance or endurance, then they may shoot for 10 hours or something and then self-experiment a little bit to see whether that suits them and they may stay between 8 to 10 hours and for people for other people who find it much easier to stick to 10 to 12 then 10 to 12 is better for them do we know how low you can go i mean i know many people listen will be wondering well you know because i i know when i lecture about your research people always say yeah but what happens if i do six hours or what happens if i eat for four hours do we do we know anything about that well unfortunately we cannot do this kind of research in in mice for a long period of time because when you reduce

our time interval then mice also eat less so we get the double benefit of caloric restriction and time restriction right and from scientific studies point of view and academics we need to differentiate that we also don't know the very long-term effect of this caloric restriction on circadian rhythm but at least the mouse experiments on the other hand have given us the clue somewhat indirectly and let me kind of take a couple of minutes to explain this there are a lot of caloric restriction studies in literature very well done from many different labs from all over the world where mice are given 70 percent of calories of what they usually need in a day. And this food is given at a certain time of the day,

maybe at 10 o'clock in the morning or sometimes at 5 in the evening. And we know that the caloric-restricted mice live longer than mice that eat their normal diet ad libitum. So that has led to this idea that caloric restriction increases longevity, improves health from many, many numerous studies. One simple thing that many caloric restriction studies did not pay attention to is when do these mice eat their food? And now what is becoming very clear is all the CR studies, caloric restriction studies, also involve time restriction. That means these mice eat all their food within four to six hours. So that means this four hours time restriction or six hours time

restriction kind of studies have already been done in mice. And those studies have shown that the mice eat slightly less, and they live longer, and they have many other health benefits. But having said that, I cannot just go and tell people they should eat between four and six hours. The reason being, I see time-restricted feeding or time-restricted eating as a public health or a solution to many of the disease or as a family solution to being in sync. So when I say 10 hours or 12 hours time-restricted eating, I feel that everyone from a 5 to 8-year-old to 80-year year old living in the same house can follow the practice and when the eating time is synchronized it also brings back family time together and this is kind of a way of life that's way beyond trying to improve your personal health it's a family

health it's a community i love that i love that i mean that is it's such a it's a it's a simple it's one thing that you change and it has so many knock-on benefits doesn't it for the whole family as you say you know sitting around a table eating together um and and again that we know that has many benefits not only for physical health in terms of how and how much you eat but also in terms of social health and emotional health and actually on the on the very first bbc uh documentary that i i ever was involved with um a program called doctor in the house which first this first episode aired in in 2015 and um i think you can still see it on youtube actually on my youtube channel it's still there but it's we use time restricted feeding i think it was either 10 or 11 hours but it was interesting they would all they put up the times on their fridge yeah and they would sit around and they'd end up eating all their dinners together because it was a family

thing we were all doing it together you know it's not that i'm doing my time restricted feeding and you're doing yours the family the the mom the dad the daughter they all did it together and that's obviously when you were talking about public health changes it's very hard to make behavior change in isolation it's much easier when it's everyone around you is doing the same thing as well right yeah so that's why i think we are always thinking about a simple behavior change that will have multiple effects domino effect and i think this time-restricted eating is one that simple behavior change that will have multiple effects, domino effect. And I think this time-restricted eating is one that simple behavior change that will have both benefits for social health, family, bringing the family together, bringing family health to forefront, all of this together. And the way I compare time-restricted eating of 10 hours to 12 hours to other practices that we do on a daily basis,

it's almost like brushing your teeth to take care of your teeth, dental health. And we do it every day. We don't even think about whether there is a cheat day. Can I cheat on brushing my teeth? Well, you can cheat, but it's not a pleasant experience. But at the same time, once in a while, we go to the dentist because we need a deep cleansing deep cleaning so similarly maybe once in a while somebody can go back to say six hours or eight hours time restricting for a few weeks a couple of weeks or four six weeks but then we'll come

back to say eight ten to twelve hours time restricting for the rest of the time in the year you know what i find incredible about this you're at a cutting-edge research institute you are to 12 hours time restricting for the rest of the time in the year. You know what I find incredible about this? You're at a cutting edge research institute. You are one of the world's most cutting edge scientists at the moment in terms of what work you're doing. Thank you. Yet some of these concepts of being part of human culture for donkey's ears, right? You know, traditional Chinese medicine have always spoken about that different organs have different times, and we need to optimize our lifestyle to suit what our organs are doing. Traditional Indian medicine, Ayurvedic medicine has also talked about these things. And I find it incredible now how we're getting modern cutting edge science to almost

echo what I think a lot of humans may well have known for a long period of time yeah so i think if you think about it humans are a very creative bunch and we have lived on this planet for more than 100 000 years so we have made those observations on a daily basis we have figured out that when we it does have a huge impact we have figured out that when we eat, it does have a huge impact. We have figured out that our daily rhythms, daily organ, our organs have daily rhythms. So I'm not surprised that there is a lot of traditional wisdom behind it. And what modern science is helping us is to put the foundation to have a deeper understanding into it so that we cannot we can not only combine it with say lifestyle we can also combine it with medication surgery or what time we should be taking our flu vaccine all of this can be now integrated to that framework

yeah and you mentioned you know once in a while like we never really forget to brush our teeth and once once in a while, we'll go to the dentist. You know, I remember, I think my mum, when I was growing up, you know, once a week, or I think it was once a week, she would fast, you know, almost, you know, again, I'm not saying that people need to do this. I just find it interesting how a lot of these concepts have been there culturally in certain, you know, certain places around the world. Sachin, I find this so fascinating, this area, I can't even tell you. A few things I just want to quickly fire through if we can. Caffeine, you mentioned wait an hour. This is a big question for everyone because everyone likes their morning cup of coffee or certainly in the UK, a cup of tea. What's the deal there? When you say

time-restricted eating window, do you mean fluids as well? And do you mean caffeine? coffee or certainly the uk cup of tea um what's the deal there when you say time restricted eating window do you mean fluids as well and do you mean caffeine yeah so time restricting window includes all food and i always tell people to to limit their coffee to that window for most regular people coffee and tea so there are two reasons one is as soon as you wake up if you need coffee to really get out of your bed that's a warning sign that you are not getting enough sleep so if you really need that coffee to open your eyes then maybe you have to try to go to bed little early to reduce that urge second is if you really have to have that coffee then a coffee or tea then you can try um without milk and sugar because at least that will reduce the

chance of your pancreas waking up because that's when your insulin response is pretty low because your melatonin may be still high so a black tea or a black coffee is okay outside the eating window for some people but it's when you add sugar and milk and cream and that sort of thing particularly in the morning and then what i say is usually our body clears half of the caffeine within six to seven hours so that means even if we had coffee at noon, then half of that caffeine is still in our system by 6 or 7 p.m. So that's the reason why some people cannot go to sleep if they have coffee or tea in the afternoon. And just to emphasize a point, if half of that coffee is in your system at 6 p.m., a quarter could still be in your system at midnight. Yeah.

Which is, you know, no one would have a quarter well some people do but you know we we know that that's possibly not a good idea that's incredible so that's even at midday yeah so that's why uh what i say is the rule of thumb is you should not have tea or coffee after lunch uh if you want to have a good night's sleep so now you can see that this is all all there is a domino effect somebody having late afternoon coffee will likely go to sleep relatively late or will not have deep sleep at night and then in the morning of course this person is waking up with insufficient sleep and will need another cup of coffee just to wake up. So this cycle will continue unless somebody really makes an effort. So what I tend to say is try this in the weekend because in the weekend, if you cut down on one cup of coffee or tea,

it's likely that your brain will react and will give you a mild headache. And in the weekend, brain will react and will give you a mild headache and in the weekend you have time to deal with that headache and then in the week they try to continue that and you'll see that you may go to sleep much better and then you can win yourself from excessive coffee yeah okay that is a absolutely fantastic tip and uh it's amazing how many of these recommendations we're talking about actually were separate chapters in my book. It's just incredible. One of them is called Enjoy Your Caffeine Before Noon. So I'm like saying, guys, if you love it, enjoy it, fine. But for me, I think, because I've seen it so many times past noon,

I've seen problems. And people are so attached to coffee and caffeine that so many people say, oh, you know, it doesn't affect me. It doesn't affect me. And when they start reducing it, they suddenly see how much things start to improve. I don't know if you've seen that at all. Oh yeah, I do that once a year. I actually completely stop caffeine for two to three months. And that's when, that's the golden time because that's when i get very deep sleep and very restorative sleep and also my general anxiety not anxiety i would say my focus

level goes up pretty high so i can really stay focused on what i'm writing or what i'm researching on so i see all that benefit and and once in a while it's good to have that self-experimentation to try and do something it means getting off of coffee will give me maximum couple of days of headache i'm not going to die no it's a stimulant right it's a stimulant that it's a drug actually that many of us are taking every day multiple times and yeah you know you it's interesting you You get better sleep. You're more productive. All these things that actually, you know, people think that coffee makes them alert

and makes their acuity, you know, their sort of sharpness go up. But I think it was a great study from 2011 from Bristol University that suggested that all it does is bring you back up to the same level as if you never drunk it in the first place. And I found that study, although I didn't like it like it i thought i think this is probably true actually well coffee has a very different history i mean if you go back to the history of coffee this was the key for bringing coffee houses in the middle east for example and there's a nice article about how coffee houses started in istanbul and the evening social activity was around coffee and uh then for some people particularly for

people who had to wake up early and do the shift work early morning shift for them coffee was a great medicine they would actually wake up and they wake up their life in the morning yeah incredible so actually could i just you know what there's a there's a there's a tale out there if an old wives tale if you will that one hour of sleep before midnight is worth two hours oh actually is it is it the other way around basically i can't remember the phrase i think it's one hour before midnight is worth two hours afterwards in the sense that you know there's a lot of talk about growth hormone release and actually if we're sleeping before midnight we get more off that is there any truth in that at all and you or you're not familiar with that sort of research well there

is a growth hormone almost every hormone in our body has a circadian rhythm and growth hormone is one of them that goes up in the first half of our sleep. It also goes up when we have an empty stomach before sleep. If you combine those two, then going to bed early has a huge benefit on growth hormone release. Another indirect, it's kind of a social constraint that we have. Irrespective of what time we go to bed, because of our job, because of our children go to school or something else, we all have to wake up before, say, 7 or 7.30. So in that way, indirectly, if you go past midnight to go to your bed, then you are reducing the number of hours you sleep. And that has been shown in multiple studies, epidemiological studies, that people who go to

bed later actually get less sleep. So when they get less sleep, they also get less growth hormone. And when you have less growth hormone, of course, for people like us who are past our 20s, we are not growing, but growth hormone does another very important thing. It actually repairs. A lot of the repair that happens in our body is driven by growth hormone. Most of the stomach lining repair that happens every night is partly driven by growth hormone.

So in that way, going to bed early has a huge impact on having better growth hormone spike and having better repair throughout our body. Yeah, absolutely incredible. But Sachin, you have been working hard, obviously, in your lab, but I'm pretty excited that your book is about to come out all over the world and here in the UK. It's called The Circadian Code. What are they going to find out when they when they when they get your book what can what are they going to learn is that you're going to sort of talk about research because about practical tips for them yeah can you tell me a little bit

about the book and what's going to be in it yeah so the book is uh really my first attempt to let people both the general public and also healthcare practitioner healthcare workers to learn a little bit about circadian rhythm. So it's a nice mix between what is the science behind circadian rhythm and how people can use this science in a very simple way by timing when they should eat, when they should sleep, and what they should eat. There are also a few things about what they should eat, when they should exercise, because we don't have too much time to exercise. Can we have a peak time when we can exercise maybe less and get more benefit? And the book also talks about how to

take care of your circadian rhythm to reverse some of the diseases. So it goes from simple heartburn to cancer. And throughout the book, we also have examples of people who have used very simple tricks to nurture their circadian rhythm and get the wisdom of the body and what they have achieved. So this is a very interesting book that goes back and forth between science and how to use the science of circadian rhythm in real life. Wow, Sachin, having seen you speak on both on your amazing videos on the internet, but also speaking alongside you and watching your talk, and it was just phenomenal and breathtaking.

I can already get a sense that actually this book is going to have, you know, personal story and anecdote weaved alongside science and cutting edge research. So I absolutely cannot wait to get it. Guys, for those of you listening, I really would recommend you follow Sachin on Twitter. And, you know, really, I think this is one of the most important scientists currently in the world in terms of doing research that can actually transform what we do with our patients and, you know, transform the way that you're living your life. And for me, what's really key is that a lot of what Sachin's research is bringing to us that I'm starting to use with my patients is that, you know, it's pretty achievable. It's pretty

achievable. A lot of these suggestions you make are free of charge. They don't cost any money. You know, it's very, very accessible for people. And I'm, you know, I'm delighted that you could spare some time and I'm, you know, going to be getting that book the first day it comes out. And I'd encourage you guys to get this book as well, The Circadian Code. Again, guys, I'm going to link to Sachin. I think you're mostly on Twitter, is that right? Or do you do any? Yeah. I'll link to all of it in the show notes. Sachin, one thing I didn't get to ask you, and I know a lot of people will be listening and wondering, you know, what about shift workers? You know, are there potentially there are some tips in the book for shift workers or are there

any simple things that shift workers can do to apply the principles that you have, you know, that your research has brought out? Yeah, so the shift work is a very challenging work. But at the same time, shift workers are superheroes, because just like superheroes, when we are asleep, they are the ones who are awake. They take care of our health. They take the sick ones to the hospitals but at the same time shift work has a huge toll on our body so we're trying now a couple of studies on shift workers the first one is on firefighters because firefighters in the u.s they have 24 hours so they're on for 24 hours and then off 24. It goes for four cycles and then

they get four days off. What we're trying to figure out is can they do time-restricted eating at least on their off days to build up resilience, to build up vitality, to build up their repair capacity so that when they do this very grilling shift work it doesn't have a lasting adverse impact on the body the second thing we're trying to see is whether they can still adopt some of the principles of course they have to stay awake 24 hours or at least they will wake up six seven times sometimes 10 times throughout the night to respond to emergencies. But at the same time, can they at least stick to eating within, say, 10 to 12 hours during their own days when they're working? That is aligned to their work schedule.

And for firefighters who are trying to do that for the daytime, for some of the shift workers who are going to work at nighttime and stay on that shift for a week will see whether they can stick to it for the nighttime when they're awake. And then we're also giving them tips how to sleep well during off days or sleep well during daytime when they get an opportunity to sleep. And these are, again, very simple tips. And sometimes many of them they can easily adopt. And we'll monitor these firefighters, San Diego firefighters, for up to one year. There will be 150 firefighters in our study.

And we are really super excited because we'll hook them up. They're already hooked up with continuous glucose monitor. So we'll see meal by meal and depending on the stress level, how many emergency calls they're taking, how their body is responding in terms of glucose. They will also have a continuous activity and sleep tracker, a light exposure tracker, all of this. So we are excited about that but at the same time through our my circadian clock app we see a lot of shift workers emergency room physicians and emergency responders who drive say ambulances they're already adopting some aspects of circadian code or eating pattern and they're finding many benefits that's

fantastic because as you say you know night shift workers are a critical part of society they they help us in so many ways whether it was hospitals whether it's paramedics whether it's a fire yeah um engine stuff you know so it's very important that we can look after them and actually give them some really useful practical tools to help them improve their health. Such a final question. Now, I have changed my own habits dramatically based upon your research. So, you know, I'm sort of pretty diligent most of the time at sticking, you know, to a restricted eating window and it varies a little bit. But, you know, I sort of normally manage to do 11 hours or, you know, at the very most 12

hours i i kind of think in my head at least if i've got that 12 hour gap without any food going through my my system that's a good thing you know have you since you started doing this research and seeing all these incredible benefits has that changed your behavior and your family's behavior? Oh yeah, my behavior changed right away. In fact, not only mine, almost everyone in our lab when they saw these mice, these mice changed their behavior. So I try to stick within, just like you, within 11 hours and sometimes I slip towards 12 hours and now I have a new criteria of how important your research is. It should not only change your own behavior, it should be convincing enough to change the behavior of your spouse and your mother.

Wow. I've been successful in both fronts. Actually, my mother, who was pre-diabetic couple of years ago now she eats within 10 hours and blood sugar has completely gone back to normal she's very active and she's approaching 70 and she's still healthy she doesn't take any medication and recently I also achieved another milestone and that is I could convince my mother-in-law. So this is the mother-in-law test for your research. And she's now doing it? She is doing it.

She is actually more diligent than me. So she does nine to ten hours max. And she's finding a lot of health benefits. Again, she's also without medication so she's completely healthy and has no complication yeah and i'm you know you mentioned your mother's story of pre-diabetes i've seen this as well in my clinic you know if if they you know yes you know the bulk of what they've done is restrict their eating window and that in itself has had benefits so for people listening i'd really encourage you guys to

to to think about giving it a go for a week or two just just see how you feel you know just you start to feel the difference one thing people might be thinking is yeah i get it i'm going to try and do 10 hours or 11 hours what happens if you know one day a week or two days a week you know i'm on a business meal out and i eat late or i come back late does it matter um if you can't do it every day yeah actually we have even done that in our lab so we have given mice one or two days off day in a week and we still see that if they are sticking to say nine hours time restricted eating during the weekdays, nine to ten hours, then going off for one or two days in the weekend still maintains the benefit. For humans, actually, for us, it's very different.

What happens is once you're used to eating all your food within, say, 10 to 12 hours, one day, personally, if I eat way past that window, first thing is I'm not hungry really to eat that food and second is if i eat that food i can really feel that the food just stays there in my stomach doesn't get digested so next day i don't feel like eating breakfast well automatically i'll delay my breakfast and then i my body kind of responds saying that what you did was not good and don't try to do it again yeah so so you kind of learn from the wisdom of your body your body will tell you not to do it again yeah and I've experienced this myself but I've also heard from some of my friends that

if you eat really late at night sometimes in the morning you you almost feel as though you've got a hangover uh even though even if you haven't drunk any alcohol but just from eating at the wrong time you can really start to mess all these systems up and feel awful the next day yeah so some of our participants actually have given it a name they call it food hangover so if you eat very late at night the next day you have this food hangover and you don't feel like eating and you're groggy your mind is foggy a bit like jet lag right it's a bit like what happens when you're jet lagged exactly yeah so half of the jet lag is just eating at the wrong time so therefore is a tip to i mean are are there some take-homes here that people can take if

they're traveling across time zones? Yeah, so that's another thing that I even personally do. I try to avoid food in flight and try to sleep as much as I can. Even though I'm not into sleep, my eyes closed, my ears closed, and my system is resting. And then when I raise the new time zone, I just have my first breakfast and dinner. So the new time zone timing just have my first breakfast and dinner so the new time zone timing I just follow that timing and that helps a lot in beating jet lag yeah wow such a look I've said to you last question about five times now so that really is going to be the end of this conversation I've really enjoyed chatting to you about all these you know different

areas I want to thank you that for doing this research because i genuinely do believe that you and your team are helping to create really big change in the health of people all around the world so thank you for that and thank you for giving up your time today professor sachin and the panda thank you thank you rangan i'm really glad that i'm on your show and you're doing something very critical because we as scientists, we do all this research, but getting this research to the mass is something that we don't do well because we don't have that opportunity. So for you, giving me this opportunity to be on your show actually is that missing link that you are filling out for many scientists. So I'm really, really thankful to you. Thank you.

That concludes today's episode of the Feel Better Live More podcast. So what did you think? I think the information Professor Panda shares is frankly incredible. And actually what I love the most is how actionable the advice is. For me, I almost always eat all of my food within a 12-hour eating window. I have experimented with shorter windows, but find that 12 hours works super well for me and is very, very sustainable. This is also what many of my patients report back to me. this is also what many of my patients report back to me.

Just a quick word of caution, if you have type 2 diabetes and are on any blood sugar lowering medications, it is worth talking to a healthcare professional before you go for prolonged periods without eating. As always, please do have a think about one thing that you can apply from what you heard today into your own life. Are you going to have a go at changing your eating window? Have you already done so and experienced benefits? Whatever it is, please do let Sachin and I know on social media. You can find Sachin on Twitter. It's at Sachin Panda. That's S-A-T-C-H-I-N Panda. You can also find him on Instagram at Sachin.Panda. So

please do tag us. Please let us know. And if you can, use the hashtag FBLM so that I can easily find your comments. If you want to continue your learning experience now that the podcast is over, please do visit the show notes page. That is going to be drchastity.com forward slash 81. Sachin's book is available to buy now. It's called The Circadian Code, Lose Weight, Supercharge Your Energy, and Sleep Well Every Night. It is a brilliant book. You can get a link to purchase it on the show notes page as well.

Again, drchastity.com forward slash 81. Many of the things that we discussed today on the show, including a 12-hour fast, enjoying your caffeine before noon, and even sitting around a table once a day to have a meal, a lot of these things are topics that I wrote about in detail in my first book, The Four Pillar Plan. I talk through patients who have put these things into practice and describe a lot of benefits. So if you are interested in learning more, please do pick up a copy of that book. It is available in paperback, ebook, but also as an audio book, which I am narrating. I know there are many international listeners of this podcast. If you live in the USA or Canada,

just a quick note that that first book of mine, The Four Pillar Plan, is available in the USA and Canada, but it has a different title, How to Make Disease Disappear. Now, if you do enjoy my weekly shows, please do consider supporting them by leaving a review on Apple Podcasts or whichever platform you listen to podcasts on. It really does make a difference. You can also help me spread the word by taking a screenshot right now and sharing with your friends and family on your social media channels. You can also do it the good old-fashioned way and simply tell your friends and family about the show. I really do appreciate your support. A big thank you to Richard Hughes for editing and Vedanta Chatterjee for producing this week's podcast. That is it for today. I hope you have a

fabulous week. Make sure that you have pressed subscribe and I will be back in one week's time with my latest episode. Remember, you are the architects of your own health. Making lifestyle changes always worth it because when you feel better, you live more. I'll see you next time.