The PERFECT TREATMENT For Diabetes, Weight Loss & LONGEVITY | Dr. Satchin Panda

I think it's fair to say that the research you piloted in your lab is largely responsible for this phenomenon that we call intermittent fasting is that fair to say yeah actually that's the first time we exactly 10 years ago we published the first paper and that was done in mice and in mice we did this experiment where we fed the mice for eight hours the at the same number of calories as the other mice but they were completely protected from metabolic diseases and we were surprised so initially when we published the paper we're a little skeptical whether it would work in humans but before we tried in humans other people tried it and and then it took off we called it a Time restricted feeding because of the correct scientific term um but now it's very popular as intermittent fasting specifically age 16 or 10 12 those kind of diets yeah I mean there's no question your work and your research is hugely influenced the way that I practice medicine and what I do with my patients and you know I think it would be a good place to start this conversation would be to really help us all understand what happens in our body when we have a period of time when we're not eating yeah so my research background is circadian rhythm or 24 hours rhythms which means that our body is actually designed to be at its Peak Performance whether it's metabolic physical biochemical or intellectual performance big performance at every hour of the 24 hours today and we all evolved on this planet with 24 hours light dark cycle and eating fasting cycle so that's why we are designed to go through this at least 12 to 14 hours of fasting every day so now coming back to what happens during this period of time one thing is this fasting has to be consistent from one day to another consistently at the same time so that our body is internal program recognizes that fasting is going to occur so there is a lot of preparation in any internal preparation the Circadian rhythm does that preparation so after your last bite of the dinner for example if it happens at six o'clock in the evening then although your mouth finish chewing the food and swallowing and that food is going to be digested for next five hours so the first five hours of your overnight fasting your body is actually not fasting it's digesting the food and then after five hours uh approximately five hours the food goes to intestine and then nutrient absorption happens for the next few hours and during this time the body is using most of the glucose and stored glycogen for fueling our system and then slowly when it runs low on glycogen so which happens maybe seven eight hours or even 10 hours after our last meal then it slowly begins to burn a little bit of fat and when the fasting period aligns with your sleeve then there is another magic that happens that is a gut lining and many parts of our body actually gets a lot of damage throughout the day and they have to be repaired and that repair process happens only when we are in our deep sleep and also we are fasting ah we don't have too much food to digest so after nine to ten hours this is when if you're asleep then um your pituitary gland will produce growth hormone that will travel to many parts of your body including the gut lining and to trigger the repair process so that's when a lot of the repair process will happen your gut lining will get repaired many other tissues will get repaired and then after maybe 12 hours 12 to 14 hours that's when a body will produce enough will break down enough fatty acids or stored fat to produce little bit of ketone and this Ketone now begins to fuel your body and then Ketone is also very recent discoveries suggest that ketones are anti-inflammatory because they affect the immune system the immune cells also like Ketone in many different ways one is they can use it as fuel Ketone is a fuel and second is ketones are also signaling molecules so that means they can instruct the cell to do to turn on different kind of programs so one of the programs that turn on is anti-inflammatory programs yeah what we're also learning is this is just the tip of the iceberg because until now no one has actually done a very systematic experiment even in laboratory Minds to see what happens during this 14 to 16 hours of fast in different organs as we all know we have at least a couple of dozen different organs and then our brain different parts of the brain is also very different so only recently we started doing that and what we're finding is it's amazing like when we go through this fasting uh if we compare this so let me dial back and tell you what experimentary did we we took the same mice um the same genotype they are born to the same mom with the same microbiome one group of mice got to eat whenever they wanted the other group of mice were given food eight to nine hours every night because mice are nocturnal and then after a few weeks we took out um 20 plus different organs and brain regions from this mice in every two hours over 24 hours to say what is actually going on during this fasting process and then we looked at all the genes in the genome so that's 22 000 genes in each of these 20 plus organs at every time point in male and female mice so it's a huge experiment and this is something that has never been done even in caloric restriction and other types of nutrient intervention so the number one thing that we found is by imposing a strong feeding fasting cycle we could see that nearly 80 plus percent of the genes were changing what time they were turned on or off or how high or low they are going up or down wow so that means really by changing your eating time you can be the master conductor of your all whole genetic program and that was amazing because in many previous studies people just look at one organs a liver or the gut or fat tissues or muscle and they find few hundred genes change it but when you cast a wider net so that means it impacts almost every organ in our body this is huge as a medical doctor I'm always looking for a few things with my patients first of all I'm looking for what is the root cause of why this person's come in not necessarily the symptoms the symptoms important to me but it's more important for me to understand what's driving this in the first place and I'm always looking to see how can I help my patient go further and further Upstream what's one change I can help them make that will have multiple Downstream benefits and what I hear with this new research that you guys are doing is the timing of your food intake as you say can be this master conductor it could have multiple effects on genes inflammation immune system function all kinds of things and one thing that's always fascinating about your work is the whole the whole conversation around nutrition for many years and even now is still dominated by what we should be eating you know should it be fat carbs protein What proportion and I'm not saying those things are not important but your research beautifully demonstrates that timing a food intake is something we also need to pay a lot of attention to yeah so it's very intuitive and it's very simple to follow as well so for example I don't know about you but I cannot remember how many calories I had yesterday and what fraction of that calorie was uh simple versus complex carb uh how much was protein fat or carb so for implementing in day to day life although these are very important quality and quantity of nutrition the timing becomes very easy because we all know what time it is uh we we schedule our whole day around time another thing that we are finding is when people control the timing of their food then as I mentioned from our surprising discovery with gene expression data they also seem to sleep well and once their sleep improves then the repair process improves and once somebody sleeps well then the food craving and and craving for energy dense diet that also goes down so that means by controlling timing we can inadvertently change the nutrition quality and quantity and that's now seen in many clinical trials with time restricted eating or intermittent fasting people although they are asked to eat within eight nine or ten hours window and then leave the rest as fasting when you go back to analyzing what they act um then what we find is the modestly reduce that calorie intake by somewhere between five to ten and in some cases some people can reduce even by 20 percent which is pretty good because intentional calorie restriction is very hard for people to reduce calorie by even 10 to 20 percent every single day is very hard so you're saying the side effects the people focusing on a particular eating window whether it be eight hours or 10 hours or 12 hours whatever it might be you're seeing side effects that actually people are also consuming less calories without actually trying to reduce their calories yeah because um previously we thought some nutritionists um I had imagined that when people are going through a long period of fasting they might Gorge and eat more um but we we find exactly the opposite people reduce their calorie second thing is since there's sleeping well then they also improve the nutrition Choice um so in almost every study we find people reduce their alcohol intake of course there is less opportunity to drink alcohol um and then they also reduce processed food and we don't know why but it may be because they're sleeping well because a sleep deprived brain actually looks for highly processed food nutrient dense diet and when people sleep well then they can take that decision um I think everyone intuitively knows that even if they don't understand the science I think everyone knows that experience when they haven't slept well you know yes you can talk to the science of leptin and ghrelin and the hunger hormone goes through the roof and your satiety hormone goes down but actually I think we all know when we haven't set well we're we want more caffeine yeah we We crave more food you know this happens to me a few days ago we're hungry all the time and you're not craving yeah healthy Whole Foods at that time you're craving Sugar High dense you know high energy dense foods yeah because your brain actually gets confused how long it will stay awake and since brain consumes a huge amount of energy by unit Mass that's why it kind of programs you to eat more because it doesn't know how long it will stay awake um so that's one side effect that you see so by by tuning your timing and knitting within eight to ten hours you can also reduce calorie and improve nutrition quality and um so that's where all the quality and quantity of nutritions are very important by focusing on timing one can improve those two aspects too so let's go into timing okay lots of things happened in the body when we have a period of time without Foods Ketone production uh reduction in inflammation change in genetic expression ability to repair and rejuvenate better but I guess there's an ideal body clock that if the modern world didn't drive us to do certain things at certain times that we could all beautifully follow and then there's real life for many people so let's start off by going what does an ideal body clock look like for someone let's say they wake up um I know you're a big fan of saying that we should try not to eat for the first hour after waking up is that true and if so why is that um so most of us when we wake up we we're waking up to an alarm clock um um we have to go to office or do something or take care of the children so that's why we're waking up in the morning so that means our sleep hormones are still high although we just dragged ourselves out of the bed our hormones particularly melatonin is still pretty high and that takes an hour or two to go down and within 45 minutes of waking up our stress on one cortisol reaches its peak so this is the time when you can say changing of the guards that happens in the morning so the Sleep hormones are coming down the stress hormones are going up and your body is actually not ready to digest food and a similar to nutrient perfectly because melatonin inhibits glucose induced insulin released from the pancreas so that means within an hour of waking up um most of us still have pretty high level of melatonin which can inhibit this insulin release so if we eat something or drink tea with milk and sugar to process that a body has to produce and release sufficient amount of insulin which may not happen properly in the first one hour so in the first hour yeah I love this changing of the garden analogy particularly is you're in London at the moment so I think that's a very practical tip that everyone no matter what diet they choose to follow no matter what culture they're from no matter what country they live in that seems like quite a good Universal principle for all of us whenever you wake up for the first hour don't eat any food but you're also saying no coffee or tea with milk and or sugar so does that mean according to this model a black coffee or a black tea is okay at that time or would you still advise that gets pushed a bit forward as well well uh many people ask me why can't they have one small teaspoon of sugar a little bit of milk so for an average sized person like me if you drain all of my blood um you'll get around five liters of blood and since the glucose concentration in my blood should be below 100 milligram per deciliters that means you'll get maximum 5 gram of sugar from my blood so that means even if I drink a tea or coffee with half a teaspoon of sugar so that's 2.2 grams of sugar if that's not processed properly then my blood sugar level will shoot up to 140 or 160 around that wow so that's why even and you're saying at that time you're not going to be able to or you're unlikely to be able to process it properly properly because you've still got these sleep hormones melatonin and the stress on the cold so they're kicking around the system still yeah which is potentially going to interfere with the way that you process that sugar so if you do want to have a hot drink when you wake up like many people do yeah you would advise keep it black basically give it black and um or herbal tea or something and yeah because some people just need that hot drink to to start their day and initially I was a little skeptical because this is an experiment we can never do in mice we cannot wake up mice and give little herbalty and see what happens um but if if somebody really needs coffee or tea to begin the day because he or she is sleepy then that's also a warning sign that the person is not sleeping well so you may have to kind of interpret that you may have to go to sleep a little bit earlier in there yeah so I used to say that there are three exceptions to the coffee rule in the morning so one is if your job depends on it so for example you're a physician you are going to see patients and you you should be alert because if you make a mistake then that can be quite deadly literally second is for Public Safety if you're driving and we know in the U.S one in three drivers in the morning is sleep deprived that is and needs coffee and the third one is if that's the only love in your life then we are not going to deprive you yeah I think that's very really peaceful because there's a real practical element to that isn't yeah there's like there's optimal yeah that's what ideally for our biology to live in harmony with our circadian biology there's a way to live but there's also a practicality depending on your life and I think that third one yeah it's a really nice one you know that is your real yeah love in Life or that's something because of whatever's going on in your life that is something that's really important to you then that has to be taken into consideration yeah would you say ideally if you could that in that one hour after waking you would ideally avoid any caffeine as well as do you know is any of your research looked at that or or not there are other circadian researchers who are beautifully shown that caffeine actually resets our clock it's almost um the effect of caffeine on resetting or synchronizing our clock to the outside world or to coffee drinking is as good as getting strong exposure to light but I won't go to that extent because light has many other benefits that caffeine cannot do so in a way caffeine is pretty good to for many people for some people it can be a little bit tricky those who have acid reflux having a strong black coffee can exaggerate that and people may say more serious acid reflux problem but if you for example if you go back to the history of breakfast actually um people who are not eating breakfast in the old days if you go back to the history of coffee for example in Turkey and in Turkey when people started drinking coffee in Istanbul in the morning and strong coffee a lot of them they started experiencing this morning acid reflux and to reduce that acid reflux they had little food with coffee and that food with coffee became breakfast if you wow look at the Turkish name for breakfast that essentially means the food before your coffee to reduce the acid reflux effect of coffee yeah okay so morning time one hour no food if possible if you can have a drink tea or coffee keep it black what else should we be thinking about doing at the start of the day to help us robustly support this natural circadian clock that we have inside us yeah so another thing is light because a body clock is in Trend or synchronized by food but a brain clog is actually synchronized by light and light is also light also reduces slippiness we all know that because it's very hard to fall asleep in a ah lighted room and in the morning if you want to wake up your children then just open your windows and they are more likely to wake up and this is very important because many of us most of us actually don't get enough light in the morning to synchronize your brain circadian clock and to reduce sleepiness and depression so light is a strong antidepressant and it has been documented in many many studies so if you have the chance to go outside to the balcony or even open all the windows in your room you'll get good amount of light and when I say good amount of light you need around 1000 blocks of flight for 30 minutes to an hour to synchronize your clock and to reduce sleepiness and depression even on a cloudy day in England you get five thousand to ten thousand Lux Supply outdoor and if you're sitting right next to the window sipping your coffee or tea or drinking your or eating a breakfast or reading a newspaper then you're getting around 800 to 1000 Lux of light so that's one thing that you can do during this one hour time or if you have to get ready if you're in a in the bathroom and if you have a dimmable bathroom light Crank It Up and crank it up and you'll and if you have those modern bathroom mirrors that have the light integrated then that's actually pretty good because light falls straight into your eye and you can crank it up to 800 to 1000 Lux at full strength and that's a good way to get the Morning Light what about movements at this time how does that fit into our body's natural clocks yeah so exercise is always good um I mean most of the time you you don't have to exercise in the middle of the night but any exercise is better than no exercise so you can combine exercise with light exposure by going for a light walk or morning run outdoor or if you're going to a gym also choose a place that gets a lot of light so you can combine both light and exercise and circadian clock the reciprocal interact with each other so that means exercise has some impact not as much impact as food or light but the clock has a lot of impact on one is the perfect time for you to exercise and we'll get to that as we move towards afternoon yeah okay so what I like about that initial morning recommendation is that you can actually hit all three bases yeah in one go if you are able to go for a walk yeah in the morning then and you don't take a drink with you right then and you don't take a snack with you then number one you're you're not going to be eating or drinking yeah you're going to be getting exposure to natural light and you're going to be moving your body yeah so that's a really powerful thing that we can do one thing that has multiple benefits on our physiology and on our circadian clock before we move beyond that you mentioned something that felt fascinating food helps us reset our body clock light helps reset our brain's clock can you explain what what is the difference between our body clock and our brain clock yeah so uh almost every cell in our body in every organ has its own clock um and when we say clock um one thing that comes through a brain it comes from mind is sleep because we go to sleep every night and then wake up and if we think what happens during sleeps during sleep many things happen to our brain and three that can be summarized into three things one is repair reset and Rejuvenation our brain repairs itself we know that the brand takes out its um its truss and that has been shown recently in rejuvenations of the brain cells connect with each other much better synaptic strengthening and it resets itself of the for the next day so similarly every cell in our body has to repair itself and goes through this so now um all these clocks have to also be synchronized with each other so that means our liver clock should be in sync with our gut clog so that a gut has its own timing when the digestive juice is produced and it also has a better time when it can absorb all the nutrient and the liver has to process so liver also has a peak time or preferred time when it can process all the nutrients so all these clocks have to be synchronized with each other and what we find is if somebody decides to eat in the middle of the night wakes up dim light and it's some food then all these clocks they will think all the body clock they'll think huh maybe this person moved to a different time zone so they'll try to reset themselves anticipating that next day this person will also eat in the middle of the night doesn't reset to that food queue so this is why consistency is so important because actually so I see what happened if you nights ago so uh it's Thursday morning as we record this now normally for me I I have a consistent lifestyle and usually my rhythm is that I will go to bed at 9 00 pm maybe sometimes before but roughly I'll be you know in the bedroom from 9pm a bit before or asleep then and I'll wake up around five that is I'm at my best when I do that I have sort of rhythms around my life and my work that help me stick to that now on Tuesday night I came down to London and I was doing my very first live podcast event on stage in the evening so the event starts at 8pm you know this is with lights on me and my guest on stage by the time I left the venue uh it was probably about 11 15 p.m and I had to eat in early but I got back to my hotel room I was I was still wired yeah it mentally uh really had a wonderful evening and I had some you know healthy kind of food in my hotel room I had some cashew nuts I think I had some dried mango slice as well which we can argue whether that's healthy or not and even though I know your research even though I've written books referencing your research I'm a human being and I thought I just have a little bit so I was just unwinding with that yeah so I was probably eating at around midnight right yeah I still woke up the next day at five even though I didn't want to I didn't have to be up but it's like clockwork in my body I wake up at five no alarm clock yeah I thought exhausted the following day all day obviously I had less sleep I was hungry all the time at times when I wouldn't normally be hungry and so I really struggled on Wednesday this is yesterday yeah I just wasn't with it and I still don't feel recovered today even though I had a pretty good night's sleep last night so maybe you could unpick that a little bit for me yeah so that's uh it's a few things happened one was your body clock was not ready to get that food so when you add your digestive system had already gone to sleep although you didn't sleep your brain did not go to sleep your body is all the other clocks have already thought that it's time to sleep the kitchen her clothes so they they were going to sleep so when you add that food um that was not easily digest it because the gut was not producing enough acid and then the nutrient absorption didn't happen and essentially you woke up with food hangover yeah because that's what I call it as well you literally food hangover we'll be back to the conversation in just a moment now many of us struggle to find time to eat all of these incredible Whole Foods that's why I'm a big fan of good quality Whole Food supplements like this one that's been in my own life for over three years now it contains over 75 Whole Food Source ingredients vitamins minerals pre and probiotics and can help us support our energy focused digestion and our immune system athletic greens are giving my audience a fantastic offer one year's free supply of vitamin D and five free travel packs with your first order you can see all the details at athleticgreens.com forward slash live more or simply click on the link below now back to the conversation but at the same time when the when all these organs are woken up by food it's not that they will just leave the food like that they'll try to digest and at the same time they'll think that okay maybe from tomorrow rangan is going to eat at midnight so let's try to reset ourselves so so the next day they're trying to reset themselves at the same time your brain is producing other hormones that help all these other organs so there's a what we call um desynchronized clocks your brain clock and your body clocks are in different time zones and they're trying to figure out what will be your next day's schedule so that's why um you're feeling that discomfort on Wednesday yeah and you know you've got two brilliant books out there the new one the Circadian diabetes codes in this one there's something I highlighted which is if you eat or if you behave out of sync with your clock it can take you quite a few days to recover yeah that's kind of what I'm feeling at the moment I feel that one aberration right which even though it was kind of healthy Whole Foods yeah and I think this is really key it's not just what you're eating it's when you're eating as well this is a key message from your work I'm still struggling today because of what I did in that I want to say a moment of weakness but maybe maybe a moment of weakness on Tuesday nights can you explain it because I think a lot of us are doing this without realizing it we we think ah you know a little bit of this now but actually it can take us quite a bit of time to recover yeah so two things one is your story clearly demonstrated timing can make healthy for junk dining Max or mistiming can make healthy food junk so by eating that healthy food in the middle of the night when your body was not expecting it um your body reacted as if you had some junk food it's very similar to your best friend knocking on your door in the middle of the night for a friendly chat not even anything and I don't think you'll be friendly with that person too much so that's one and then the second thing is those who who are doing shift work or who travel quite a few time zones um two to three time zones it's very normal for them to understand that when you change time zone it can take three to four days and even sometimes seven days to adjust your sleep work cycle to the new time zone so the rule of thumb is it takes one day to reset your sleep work cycle by one hour so that means if you are traveling three time zones then it can take up to three hours so for in your case um if you are eating say if your dinner is usually at six or seven PM come down by seven seven only by six six thirty I'm done yeah oh man so that's like six times six time zone so that's what your body felt like you have traveled six time zones so uh it will try to readjust itself for the next six days but the good thing is you came back to your um previous schedule so you can reduce that jet lag we call it social jet lag because it's not real jet lag you are not doing jet travel but your body thought because of social obligations and social events um you ate at the wrong time so it's called social jet lag this idea that you can turn healthy food into junk food by eating at the wrong time I think it's really really powerful and it's a message that I hope spreads far and wide because this timing piece is arguably for me one of the big missing pieces when we are trying to help people change their health it's like what to do but yeah we don't tell people we don't advise people when to do these things and since I've shifted my whole lifestyle and work patterns everything to suit a rhythm that I can consistently do and I'm lucky to be able to do that I appreciate not everyone can do that especially if you're doing shift work and it's changing from day to day or every three days you're on a different pattern and we'll hopefully get to that later in the conversation every part of my life gets better gut function is better energy is better I rarely get sick you know all kinds of things start to happen and one of the most powerful things I think about the work that your lab has done is it shows that when you really pay attention to the timing of multiple things but let's say food yeah and lights right but but that's even just Foods there's benefits for weight loss there's benefits for immune function for reducing inflammation for gut function um kidney function we have honing kidney function yeah yeah so instead of trying to do something for your gut and something for your kidney and something for inflammation it's like well hold on a minute why don't we just work on an eating window that's going to work for you so let's go there to an eating window yeah you publish your first seminal paper almost 10 years ago to the dates which basically sparked off this phenomena around the world which has gone into multiple different directions of intermittent fasting yeah in the last 10 years from all the research you've done from all the research you've seen been done around the world uh with the understanding that everyone's unique and everyone's different do you think you have a universal recommendation like a this kind of eating window is going to work for most people do you know what would you have a number that you would recommend yeah so that's a little tough uh it's a tough one yeah so let's start from means we started the conversation from the morning okay and we said uh one hour we should not eat and then um when should we eat so the breakfast or the first meal ah that breaks your fast because let's redefine breakfast breakfast is actually the first meal that breaks your fast okay not the morning not necessarily the morning meal that you have to eat um so uh you have to eat your breakfast at a consistent time because of this its effect on body clock because the breakfast time actually is most powerful in re-synchronizing all your all your clocks and then telling okay so I'm in the same time John let's start the day and then the question is should somebody eat within four hours six hours eight hours ten hours or 12 hours or more um so we can do some simple math and then we'll reach what would be the ideal one okay okay so we know that after we eat after after we finish our dinner for the first for the next five hours it's not actually fasting it's digesting our food in the stomach so that means um we should have those five hours set aside and then um we should actually sleep for we should be in bed for eight hours so even if you suppose you finish your dinner at 6 PM you're not going to sleep right away because your stomach is digesting for your core body temperature is high because blood is Flowing to the to the stomach to absorb that nutrient so you need two to three hours um after your dinner to get ready for your sleep so now ah will take two to three hours after your last meal and then add eight hours of being in bed so eight hours plus two hours so that's ten hours so now in the morning you got to wait for an hour so that's 11 hours so that leaves 13 hours window within which one can choose to eat for X number of hours so nobody showed it for more than 13 hours unnecessary according to this map so now if we come back to clinical studies there are some studies where people were asked to eat everything within 12 hours every single day but unfortunately we didn't see much benefit so 12 hours every single day is not a good idea then if we look at when you say not a good idea let's say and in a your app has shown that a lot of people are eating over 15 hours 15 hours right yeah and a lot of people don't realize they're doing that yeah right because that includes of course sugar in their coffee or a little snack in front of the TV at night so if you are currently consuming over 15 hours or 14 hours right yeah moving to only doing it over 12 hours presumably is a good thing so it's a good thing to some extent but what happens is people who are um yes somebody is if someone is eating over 16 hours and now moves to 12 hours that person will get some benefit because that four hours Delta the change in reducing eating window by four hours will benefit that person okay and many different types of benefits May improve nutrition quality and then we don't know whether it will help to reduce calorie intake significantly to the point that the person will see something so there's some benefit there but you're saying some of the research when you took people and put them in a 12-hour reading when they say 12 hours in 24 where they're not eating yeah hopefully they're sleeping for seven or eight hours of those you're saying you didn't get many benefits no so again these are clinical trials with a lot of people so yeah we are comparing the averages but there are some people in those group who actually saw benefit but if we average all of them then we don't see that so from clinical trial point of view we have to always do the stats and um but you know I'm just going to pause you that's such an important point because one almost Universal recommendation I have with most of my patients is let's at least start off making sure you're eating all of your food within a 12 hour window maximum yes right so that's often my starting point and a lot of people if they can't do that or they say that they struggle I say okay you should be able to do that so let me help you get to a point where you can do that because sometimes if they've their blood sugar imbalances or hormonal imbalance sometimes or it's just conditioning yeah okay so in the 12 hours some people saw benefit but overall you couldn't say that there was a huge benefit now I guess let's dial back because every clinical trial also has inclusion exclusion criteria so that means what type of people were studied yeah and in this study uh we didn't have people who had any chronic disease so they were just overweight okay they didn't have um too much complications they didn't have high blood pressure consistently or high blood glucose even in my new book the Circadian diabetes skirt I also tell that just try 12 hours for the first two weeks yeah and then you see whether you can even do 12 hours if you can't do 12 hours then you can stop anything yeah exactly yeah so there are all these caveats to clinical trials so it's important to know what is the inclusion exclusion criteria what type of people were studied yeah second what was the Baseline eating habit because if they are starting from say 13 hours or 14 hour sitting window and they're trying to shrink it to 12 hours you may not see too much what you're talking about as nuance and perspectives and contacts something that is uh fast becoming a thing of the past certainly on social media that this kind of because this is important isn't it instead of seeing the headline of the study this doesn't work this does work it's like well hold on a minute hold on a minute let's just say this this average didn't work yeah for who what kind of people was it a man was it a woman was it did they have chronic disease did they not you know yeah and that's often missing in their kind of discourse around this stuff yeah so that's why I think uh anyone who is reading the headline has to ask these questions which type of people are studied what was the Baseline characteristic habit and health condition what did they try to do could they actually do that because in many study um if I was just asked to eat within eight hours and I never kept any record and I came back after 12 weeks and I said hey I didn't see any benefit but I don't have any record to say that I actually tried this then that's also flawed so these three or four things we have to keep in mind the Baseline characteristic what type of people I studied and whether that was monitoring whether so for example in many caloric restriction studies where people are asked to reduce calories people are also asked to diligently record all their food person size so scientists can figure out whether the reduced calorie so similarly in many of the time restricted feeding start eating studies or intermittent fasting studies we have to look for those things like wear them monitored did they really reduce the eating time and how much they reduced what does the Baseline characteristic and what kind of benefits they found so going back to 12 hours what we find is yes people can start with 12 hours and as we did the math there's only 13 hours available to you to eat to choose a window and if you can do 12 hours then that's a good starting point in all of our clinical studies what we do is we ask people to choose a 10 hour window that suits their lifestyle and this is very important because we are not asking people to start eating breakfast at eight o'clock or nine o'clock or seven o'clock or we are not even asking to skip breakfast or skip dinner we just ask them a very simple idea that try to eat within 10 hours with some caveat that your first meal should be at least an hour after waking up and your last meal should be two to three hours before going to bed so within that window you're going to choose that 10 hours that works for you and in both Mouse studies and in human studies what we are finding is if people can do this 10 hours for five days in a week or six days in a week and they can have one cheat day where they can go little bit outside the eating window we still see many benefits in people who have one or multiple items of metabolic syndrome so that means they have obesity plus high blood pressure uh High triglyceride or high blood sugar even multiple of these conditions and what we find is if they can do 10 hours for 12 weeks then we do see Improvement in almost all of these elements of metabolic syndrome some are more profound and some take a little bit longer time particularly blood triglyceride takes a little bit more time blood pressure Improvement happens within six to eight weeks blood sugar also improves in 10 to 12 weeks if they do 10 hours it's also important to remember that many people who have obesity with metabolic disease they are so used to eating over a Long window of time that it becomes very difficult for them to shrink that eating window to 12 then 10 and sinking that to eight hours becomes very difficult to for a lot of people in fact and some of couple of our studies where our collaborators wanted people to eat within eight hours although they started with eight hours towards the end of the experiment 12 weeks when we look at the real data we found that they were mostly drifting towards 10 hours so 10 hours since to be a number that many people can adopt the 18 window and it's also it gives them a sweet spot that they can still have their social life and yeah enjoy life and improve their health yeah a couple of things there for me um I agree some people really struggle initially yeah um but actually some people also find it quite liberating I found there is a subsection of my patients who in the past I found that they find like an eight-hour window where they're eating very liberating and once they get used to it yeah they actually find that they've got more energy less hunger it speaks to this idea that we can maybe train our circadian biology to a certain degree by having a consistent pattern yeah and you know as we have this conversation I've been in clinical practice for over 20 years right and I've learned that very few things apply for every single person and you have to take into account a person's lifestyle their previous history their job what their family are doing all these kind of things and so I have these recommendations but I'm Loosely attached to them because I realize that people have to be able to to personalize them you know you've done a lot of science on this right which is clearly in the times of which we live a lot of people need that site to persuade them that this is something that I should be doing but if we just zoom out for a minute and look back at our evolutionary history as humans actually it's hard to make the case that we would have been eating consistently over 13 14 15 hours and every 24 hours you know we would have naturally had these long periods where we didn't eat in every 24 hours so yes there's science to support it but there's also if we look at our lives to an evolutionary lens it kind of works as well doesn't it yeah it does and in fact uh yeah our ancestors hunter-gatherers or Farmers um they didn't have access to plenty of food and another thing was um they didn't have access to processed food so food was not ready for conserve some any time of the day so in the morning people typically spend time Gathering food or preparing for cooking and the first substantial meal was maybe around lunchtime and then in the evening after everybody came back home that evening time was very important and it's still important and if we think about human history um what we do in the first six hours of the evening after we get home that actually determines every aspect of our life because after we come home our hunter-gatherer and sisters or Farmers they lighted a fire and they cooked or grilled food or whatever they had gathered and then they shared that food so their social aspect of eating and then that's the time when people feel liberated from their daily life so you have come home you are not working for a bus and that freedom time two to three hours after dinner is very important for a lot of people and our ancestors hunter-gatherers that's the time when life changed so daytime people thought about how to work to bring food to the table and after dinner they became more creative that's when people started um singing dancing talking about philosophy and Science and politics so that's the cradle of civilization is actually in that evening time so we should not forget that so we have to keep in mind that people have to come back and and their lifestyle they have to socialize and do certain things and that dinner time is very important so going back to your question that people have to it relate not only to science but also to society and culture and how we have evolved on this planet they can keep that in context and maybe delay the breakfast in the morning because that's what our ancestors did and that also aligns with her physiology because when people are in experiments when people are isolated inside laboratory without any cue what time of the day or night it is what we have found is a hunger subjective hunger actually reaches its peak in the evening not in the morning and that makes sense because a lot of people actually will say that they don't feel that hungry in the morning but almost everybody would say that they have some hunger in late afternoon or evening so we are programmed to be hungry towards the end of the day and that hunger since its Universal everybody feels that that's also is a basis for that socializing and consuming food in a gathering and then discussing something other than how to how to make money to bring food to the table how does this fit with there's quite a lot of research that I've read which is showing that if we consume the bulk of our calories in the first half of our day compared to the second half of the day that can have powerful effects on our circadian clock on weights on sleep on immune function all kinds of things and so you know there's obviously a phrases of their breakfast like a king lunch like a prince dinner like a pauper which I think works really well for a lot of people actually yeah but how does that fit in with what you've just said which is that we are wired to maybe feel hungry later on in the day maybe late afternoon or the evening because on the face of it it might seem as though these things are quite opposing yeah so when I say that it's not that we are saying that people should just consume food in the evening okay they'll still it's true that in the first half of the day ah a blood sugar control is much better and um as physician you might have seen that if you do a oral glucose tolerance test which is looking at blood glucose X number of hours after um Ebola sub sugary drink then the same person may look normal in the morning when the glucose tolerance test is done but in the evening that person's glucose will shoot up or late night it will shoot up and you may diagnose that person as diabetic so that is this aspect of how glucose regulation particularly insulin in producing cells have their own clock so that blood glucose level suits up in the evening so that brings up what we should eat at different time of the day and the analogy that I get again another thing is our hunter-gatherers when they were lighting of the fire they are not lighting a fire to actually eat berries the lighting of fire to eat meat or a complex carb that needed a little bit of cooking so that that would become palatable they were not actually lighting fire to warm up their chips and ice cream to it yeah that's a good point so that means the biology and and the social aspect still holds good that in the first half of the day the more likely eating food that was easily palatable which already had a lot of simple sugar or easily digestible food which typically raises our blood Brokers right so that our insulin producing cells can manage that whereas in the late night or late evening whatever they were eating or mostly food that was rich in fat and maybe protein and that would help them to go through the long period of fasting overnight yeah that makes a lot of sense actually it also brings up this idea that when we're trying to compare modern humans with our evolutionary biology and hunter-gatherers there's another big piece that we miss which is many of us these days have broken metabolism yeah you know if you look at the numbers in terms of how many people yes are type 2 diabetic but also pre-diabetic yeah which means fundamentally we have issues already with our ability to maintain our blood sugar and you know our body's not functioning optimally I can't remember what the stats are now but it's I don't know so in the U.S now almost half of the adults are pre-diabetic or type 2 diabetic do you know what it is in the UK I think it might be it might be similar because it's uh yeah very similar but so therefore if we're trying to make a comparison it's like yeah wait a minute though yeah maybe they were hungry early evening and maybe there was a big part of their culture and Community around that but if you are someone who is already struggling with blood sugar yeah so you will not like those hunter-gatherers yeah then actually what you're saying from your research is that we're much more efficient at managing our blood sugar early one in the day then last one in the day yeah so this is where we have to be a bit clever with our recommendations yes do you know what I mean we use use history to help us but not to completely kind of enslave us and saying this is what they did so this is what we should do no actually yeah so we should we should break that comparison because you know our hunter-gatherer and sisters that live to the life of say 35 or 40 years old because life expectancy was less than 45 years um although a lot of people will say that's because of high infant mortality yeah so I'm sorry mortality and so but anyways the point is yes in the first half of the day our ability to handle glucose is much better so that means for the first half particularly you can plan your breakfast in a way that you can have your sweet treat or a little bit of complex carb and a balanced breakfast and then as you move towards dinner you can actually plan to have a little bit more protein and fat to help you go through the nightly fast and also to help you live with your own physiology that your insulin response is pretty bad can you summarize if most people if anyone listening to this or watching this goes okay I'm going to now try and eat all of my foods that I'm going to consume whatever diet that might be within a 10 hour eating window so first thing I want to clarify well within a 10 hour reading window can you list what are some of the benefits they may get yeah so once people eat within 10 hour sitting window um what we find is uh within few days um that may be two to three weeks they may find that sleep will improve and this is something that we find in many our patients who self-report how is their sleep it may not increase the number of hours they sleep but it may just improve the Sleep satisfaction they might actually get into a better sleep quality of sleep will improve um than those who have acid reflux I don't know the numbers in the U.S in the UK but in the US there are 65 million prescription for acid reflux written every year yeah and there is a lot of over-the-counter acid reflux medication so that means almost more than half of the adult population experiences some kind of acid reflux or stomach issues every week so we also hear that people have much better gut health within two to four weeks they will feel that um so sleeping better and then having better gut health will also improve the sense of energy in the morning and throughout the day so these are the we think that these three benefits are the positive feedback loop that helps people to sustain with eight hours or ten hours getting window then those who have pre-diabetes or type 2 diabetes with minimal medication for example metformin they may also find the blood sugar control will improve particularly the night time or the the time period in which they are fasting um at least in that period 14 hours or 16 hours the blood sugar will remain much better under control then surprisingly many studies although we haven't connected how it works so we find that people with hypertension they improve both the systolic blood pressure and diastolic blood pressure and that can happen between six to eight weeks after trying this regimen so the flip side is if uh people are already on hypertensive drugs then after four to six weeks they should actually check their blood pressure to make sure that they should do some dosage adjustment I think this is just I think we should pause that because I think this is an important points there are all these incredible benefits on the other side of this yeah and so one of my cautions with patients and again I'd caution anyone listening or watching if you have type 2 diabetes or if you are on any blood sugar lowering medication from your doctor yeah you might want to just have a chat first because yes because your blood sugar starts to come down you may not need that so what I've always done is I would stop like something like glucoside for example which can drop blood sugar I would usually stop that when we're transitioning over and then revisit this in a few weeks to see you know a few months you know what do we need now metformin usually is okay but blood pressure medicines you would agree with that be cautious with those torture dots at first yeah um so if you have some health issues there are benefits right but what about that person listening who goes well actually you know I feel I kind of feel okay like I haven't got pre-diabetes I haven't got much of a weight issue what are the benefits for me Dr Panda of eating all my food within a 10 hour eating window I think everybody would agree that they need a little bit more energy yeah and they may not have other health issues but almost many of us they we have a little joint problem where you feel a little pain and um overall other things that we are finding biochemically and with all these gene expression analysis what we're finding is the kidney function improves um our muscle repair also improves uh there are now new studies showing that circadian clock is involved in repairing tendons and ligaments um so injuries injuries particularly recovery from injuries and if we think about it actually every day will we endure some some of our giant ligaments and muscles we are on a continuous Rejuvenation process and that's why I say that just like a brain when it sleeps it resets rejuvenates and repairs itself almost every tissue in our system repairs itself and whether you're an athlete or Elite athlete or just a recreational athlete it also helps to repair recover from injuries what about athletic performance yeah do we have anything on that yeah so athletic performance at least are mice are more athletic so mice become more athletic yeah so when you start the mice is eating window they become more athletic yeah so in mice it's a it's very profound um so in the 10 years ago when we published this paper um one question was well since this my sighting within A2 nine hours at the actually is the muscle weak so that they cannot perform well so we have to put this mice on treadmill to measure how how long they can be on treadmill before they become exhausted and cannot run anymore it's a normal Mouse in the treadmill condition the inclination and resistance that we applied normal Mouse should run around 60 Minutes on treadmill and then if the mouse is eating unhealthy diets that would run around 45 minutes and this mice that it within eight hours surprisingly they could stay on the treadmill for 120 minutes so twice longer than regular mice that were eating normal healthy diet but whenever they wanted so that was really eye-opening for us to see the exercise performance improved that much so coming back to humans although Elite athletes and people who are training pretty well they have already maximized optimized lifestyle but what we find is even among them they do see some improvement in the athletic performance whether it's strength training or endurance running and this is very important because if you are competitive then a fraction of a second actually makes the difference so this is something that if we combine your Optimum Nutrition optimum sleep with Optimum Nutrition timing that can actually help yeah and for many bodybuilders um they're asked to eat in every two to three hours and I have heard that a lot of them actually put certain alarm to wake up in the middle of the night and eat and some of them when they start doing this time yesterday eating or intermittent fasting with Optimum Nutrition ah first thing the report is the acid reflux they thought that acid reflux is so common that it must be normal but it's not so that acid reflux goes away and they actually feel more energetic because there are many bodybuilders who don't feel that full of energy throughout the day yeah I mean I found this whole area faster because I I believe that live in harmony with your circadian body as much as you can yeah and frankly there's very few areas in your life that won't improve as a consequence yeah whether we talk about health or Beyond health I really passionately have seen that with patients I've experienced it myself so the point where you know it's interesting I I rarely come to London anymore to do podcasts right but for whatever reason I'm here this week and I've got you know a busy day and I know I'm aiming to get a train home tonight from Houston Station at around 7pm which kind of means I probably won't walk into my house till 9 30. yeah now I that means I've got two options one option is I can wait till I get home and have a really nice kind of healthy meal that technically you would say is better for me you know I know the ingredients I know what's in it maybe it's something my wife cooks earlier for her and the kids that I can eat when I get back I've done that before but I realize for me either I skip dinner but if I'm hungry I'm better getting something as healthy as I can at Houston Station yeah eating it on the train and finishing eating by about seven seven fifteen something like that and I found for me I can have a and this really speaks to this idea you said before that you can make healthy foods junk by eating at the wrong times yeah I've realized for me I'm better off getting something where I compromise on let's say nutrient quality a little bit and have it at 6 45 7pm rather than weights and have a a better Whole Food meal later in the evening which I think really speaks to the point that you're making yeah the other thing I wanted to comment on is my son's 11 and one thing me and him do most Saturday mornings if not every Saturday mornings go to the local park run which is a 5K run around the worker park right which you know these apartments are transforming communities and people's yeah people's lives in so many ways and what I'm trying to do with my kids is help them start to pay attention to what happens when they do certain things for example oh I feel tired and sluggish I don't want to go oh now that we've gone how do you feel now rather than you know Daddy telling him yeah it's like oh yeah I've got more energy now even though I didn't want to come I've got more energy and I've also asked somebody to say just pay attention now to what time we eat the night before and how you're doing and how your time is on a Saturday morning and I think he's already started to draw the comparison when we stick to the early meals on a Friday evening my sleep splatter and I'm running better on a Saturday compared to do you know what I mean so I'm I'm taking your science and I'm trying to actually instead of teach it to my son I'm trying to just help him start to pay attention to oh do you know what I mean no so this is uh you're doing the right thing because um this is a Time particularly Tina's time that's when the the kids uh after the after they get into late middle school and high school um this is when all of our security and disruption happens right because that's when they get a lot of homework they have to stay up late into the night and when they stay up late into the night they think and often they are also told that your brain cannot function unless you have a late night snack and they get used to that late night snack and staying up late in the night and in the morning they are sleep deprived and they have to rush to the school and I don't know what is this school start time here but in the U.S for example um most of the school start time used to be 7 30 in the morning before the pandemic started so um in collaboration with Horacio D Iglesia who is a professor at um in Seattle he did a very simple study what he did was he was looking at sleep and we know that many teenagers starting from middle school to high school and college they are sleep deprived and that's also the time when the the circadian clock tells them to wake up little later than adults and also toddlers so the experiment was to delay the school start time by an hour and to track the students before and after the school start time was delayed so we tracked nearly 200 students in two different schools their sleep habit their activity and their academic performance and when school start time was delayed by an hour these kids got 35 minutes more sleep extra sleep and when they got that 35 minutes extra sleep then many parents should think that now kids are sleeping more so they're not doing their homework and that 35 minutes is coming from this homework time so their grades might go down but actually what we found was the Grits improved by four percent and a four percent great Improvement is is can be pretty big for people who are struggling or those who are getting big credit they can go to a grid so this is an example where small chains uh starting from middle school or high school can have a huge impact not only on their health but also on the academic performance and if we go back to now actually in the pandemic quite a few things happened one was the kids were at least in the US many kids were always on zoom and they lost track of that regularity and their life they didn't have access to a lot of bright light there was social isolation and um and they're also watching a lot of TV and eating late Into the Night um so now this has become and also since there was online education a lot the time at which people had to Res submit the homework also uh inadvertently now has become midnight so in high school and colleges at least in the US they deadline for submitting your homework is midnight so that means it's now institutionalized that students should stay awake until midnight to finish their homework and submit it and this is um so this is circadian chaos this is circadian chaos which is now institutionalized um at least in the US uh about all high school and and colleges so this is something that I've got to be honest I find incredibly frustrating um particularly with schools but it applies to adults as well which is also what happened over the last two or three years is that schools that weren't whether using technology that much for their kids now everyone's on technology and even though a lot of schools now well in the UK are completely back to normal the screens have stayed yeah right so they're now in and they're not going back and a lot of the homework that's now being given is on screens whereas three years ago it wasn't being yeah and I don't think a lot of schools realize the disruption like I speak in a lot of schools I get asked to speak about stress and resilience and what people can do um why are so many kids now depressed and anxious and I'm thinking the problem is there's fundamental well hey there's too much pressure on kids at an early age that's a slightly separate issue in my view um but the way they're being asked to work now is fundamentally going to mean that most of them are going to become sleep deprived even if they're not sleep deprived technically in terms of the amount of hours most of them will have been looking at screens probably in the last hour before beds yeah so therefore even if they are falling asleep they're not going to get the same depth and quality of sleep and you maybe speaks out because a lot of adults are actually doing that as well you know 20 30 years ago you couldn't do that after dinner you get most of you couldn't really work now we can get back on the emails and keep going until late yeah so we mentioned food we're mentioning light as big drivers of our our body circadian rhythm you know we you mentioned light in the morning how important that is for your brain's clock what's going on with light in the evening and what can we do to kind of mitigate that both for children but also adults yeah so light is extremely important when it comes to Brent Clark and in the morning you got to re-synchronize a brain clock to day night cycle and it reduces depression brings alertness and for the last 200 000 years humans never saw too much bright light after Sunset the light the fire light or the candlelight is very dim and it also doesn't have too much blue light yeah so we are designed to see only dim light or orange color light in the evening and even if you go back to the history of light in the UK in 1850 between 1850 and 1900 um the cost for lighting up average size UK home for two to three hours every evening was substantially High it used to consume almost a week's worth of income so people actually didn't light was expensive so only in the last several last 50 years or so the cost of lighting I'm not talking about your entire gas bill and all these bills just lighting is less than one percent and actually less than 0.5 percent of an average household's income wow so we have uh plenty of light and in fact now we all want bright light so um light pollution in our house has become a big deal second is the screen time we are essentially looking at rectangular pieces of glowing objects until from the time we wake up until we go to fall asleep yeah and so what a what a time to be alive eh of course there are many benefits I'm just you know having a joke yeah yeah and uh you know we are also talking now we are thinking about metaverse where the light will be actually attached to our head looking at rectangular pieces is not enough we have to actually attach it sorry since you're UPS if you are enjoying this content there's loads more just like it on my channel so please do take a moment to press subscribe hit the notification Bell and now back to the conversation so uh this is kind of the silent epidemic that has begun and I think from circadian point of view we are at the same point as uh what used to be the what I call the lead and asbestos moment so this is a time when we realize when you're beginning to realize what is the widespread health impact or disruption of circadian rhythm disruption by having exposure to too much light ambient light and also screen time and reducing sleep or reducing Sleep Quality and eating at the wrong time all of these three are converging but just like smoking suggestion or lead in asbestos took almost a generation to correct I guess we are at the very beginning of that correction phase and it will take us almost a generation but at least few things that we can begin to implement in every family and you are doing pretty good uh awesome setting an example for your kids is to come up with simple rules that two to three hours before bedtime that should not be any bright light exposure so at home for example now is a good time to put almost all your lights and dimmer so that you can dim the light not flip switch it on or off and then use indirect light so that means light that doesn't illuminate your face but actually the workspace um table lamps for example in the old days so those kind of Lights and also for all of your devices uh make sure that your all your devices are set to the minimum brightness because if that is your default um setting then during day time of course most of the devices will crank up the brightness to compensate for the ambient light but at night time at least they will go back to the minimum brightness so go into your computer or your phone and change the settings so that it automatically starts like or all that settings you're talking about where it it changes according to the ambient lights yeah so most of the devices now will change according to ambient light but they will always come back to uh in the dark they'll come back to your default setting so make your default system where you are really low yeah and then almost all rectangular pieces of glowing objects also have night shift feature and this is really gratifying for me personally because 20 years ago uh in 2002 December actually we published this paper showing uh demonstrating that this blue light receptor called melanopsin is important for resetting our clock and and also important for Sleep regulation alertness and depression all that stuff and seeing that being translated to billions of devices is very gratifying but so now you can go back to all your devices and set the night shift or night light whatever picture it is so that means it will actually change the color composition of the of your screen to from white balance to a little bit orange in color so even if you are working now and you can see your job requires you to even if your kids have to do homework at that time their school requires them to you're saying that by doing this we can mitigate the effect that that's going to have on our Sleep Quality and our on our sort of circadian rhythm yeah so at least you know just like for waking up we have an alarm clock for going to bed these are the nudges that will come in automatically that our screen will become a little darker and change its color so at least for me personally I feel like okay so it's time to wind down yeah and prepare for bed when you know kids yeah it must be really gracifying for you because I guess one of the reasons I guess from home screenshot before to become a scientist was to really help create change in the world and how phenomenal that you've been involved with research 20 years ago with a discovery that you and other labs made about melanops then and now you're seeing this widespread adoption into devices that it must be incredible to see work in the lab now being translated to real life which is incredible I want to really acknowledge you for that because it's it's no small feat to be able to do that and that that has a massive impact on people's lives on that you previously said I know there's science on this that blind people even though they're not well blind people can still detect when there is bright outside lights yeah what's going on there that was the mystery for a very long time that um majority of blind people they cannot read the newspaper they cannot find their ways but they can actually sense when they're next to a window or when they're outdoor or indoor so they can sense that brightness of light and even blind mice mice that have genetic mutations that make them blind they cannot navigate through a maze but they could actually sense light in the sense if you change the light dark cycle then the circadian clock would track the new light dark cycle and blind people also when they travel most of them cannot readjust the new light dark cycle so how are they doing that so so that was the mystery and that's what we saw that that this melanopsin and the reason why it is called melanoxin is this is an option there is a light sensing proteins in ah typically called auxins and this option was initially found in the melanosomes or the pigment producing cells and the frog's skin so this was discovered in 1998 or around that time so this is a clear example that basic Research into how a frog adopts its screen skin darkness in response to Daylight or sunlight led to the discovery of this melanopsin present in frog and then when the human genome was sequenced then we also found the same gene to be present in humans and subsequently other groups other scientists actually showed that this particular melanoxin Gene is turned on in very few cells in the retina and these cells actually survive um the genetic blindness that affect a lot of blind people and Blind Mice so that set the stage for us you know science is always a communal activity and it all always Builds on previous research so I won't say that I had full credit for it but then this the stage was set to ask this very simple question is melanoxin present in very few cells in human retina or in Mouse retina responsible for the light perception that was already documented for almost 75 years that happens in blind people and Blind Mice so that's what we discovered in 2002 that yes this melanopsin is the light sensing protein that resets our clock and that's present in very few cells so for example in a human retina we have 14 million rod and Cone cells that give give us the uh outside View whereas malinoxin is present in maximum 5000 cells and another uh interesting fact is um since 2002 people have been studying this melanopsin in Mouse retina or rat retina and based on that we have devised all these night shift feature or brightness setting all this stuff but only two to three years ago for the first time we could actually measure what this melanopsin cells look like or how they sense light in human right now for the first time only three years ago so this is also another example how the honest taxpayers money that goes to research actually helps make discoveries in weird animals like frog skin or mouse in a laboratory and that can have a huge impact on how we live long before even way before when we can do those experiments in human retina so melanopsin is just present in retinal cells so not on the skin no not in the skin so people who are blind yeah although they can't see you know that's a um I guess that's a nervous simplification but that they're base they're basically still can sense like can sense the light and set their bodies circadian rhythm that's that's really powerful isn't it it's really really powerful um just to close off then the evenings right because there's a really nice symmetry where you want at the start of the day one hour without eating get some light get some movement if you can those things are great at the end of the day you're saying two to three hours before beds not to eat so you almost kind of start in the end are quite similar in some ways but very different in other ways in terms of an you know instead of bright light in the morning you now want dim lights in the evening um Candlelight firelights if you are on your screens change that one thing we've also done at home which has made a massive difference I have these low blue light bulbs now yeah in all the bedside lamps yeah it's and you can feel it and actually once we run out recently and we changed it to a normal yeah like low wattage bulb I couldn't believe how bright it was I thought well for years this was what it was yeah uh it makes such a difference yeah and you feel it you feel more relaxed so I think again that's a very simple thing that people can do that will make a difference Go Master easting Windows yeah Okay so we've started 10 hours yeah appears to be a pretty good Universal recommendation that most people tend to find Works around social life work life and what they're able to do now there's a huge Trend these days in the kind of low carb or keto community to skip breakfast and maybe go even more aggressive like eight hours and maybe uh you know first meal at 12 finish eating by 8pm or I know some will go even later they use coffee to get them through in the in the morning and don't feel hungry at all so often it'll be two or three p.m they start but they'll leak quite late till let's say 10 p.m so they've actually got a compressed eating window but it's towards the end of the day yeah so I just want to get to some of the subtleties here compared to what most people are doing which is eating across 15 hours right we want to reduce that great let's go 12 hour minimum you're showing a lot of benefits so people get to 10 hours okay fantastic are there increased benefits for some people when they go even lower to let's say an eight hour reading line or a six hour eating window I guess that's the first part of the question and the second part of the question is what do you think about yes we have to personalize it to our life but if we have an eating window that's my understanding of the science is that eating windows that tend to be earlier in the day tends to be more in harmony with our circadian biology but I have also seen people get benefits even though they're doing it late into the evening so can you maybe put some of that together for us yeah so um compressing eating window to a narrow interval is almost like exercise any exercise at any time of the day is always better than no exercise so similarly compressing getting window to eight hours if you can do or six hours and eating healthy nutrition within that eating window is also a pretty very important and we have to stick to that because sometimes what we have seen through our public facing my circadian clock or the research is some people tend to compress that hitting window Too Short maybe four hours or six hours at the same time they they try to improve the nutrition quality so the eating only salad or they reduce their calories and they may be eating less protein or less fat and particularly for women that can and they're also more active so that can trigger something what we call relative energy deficit in sports so many athletes particularly women athletes they report this that most authors who do Triathlon or marathon runners women they become amenoric they don't cycle anymore and they feel that it's so widespread that it's normal which is not true so that shows that by reducing calorie or eating within a very short time and at the same time not paying attention nutrition quality can put you into this state where your neuroendocrine system can malfunction but if you are doing well with nutrition quality then we haven't seen any study and that compare this very short reading window with longer eating windows so what we have seen is for people who are obese diabetic or pre-diabetic overweight if you put them on six hours or four hour sitting window then they have lot of adverse event so for example they can feel dizzy they can feel extremely low energy and sometimes even nausea those kind of stuff can happen but those who are adapting to it they have to pay attention to nutrition quality we cannot look at longevity or overall health comprehensively in humans but there was a study that just got published a couple of weeks ago in Science magazine it's not even in full print it's only in online and I think that's that relates to this question so this is a very simple calorie restriction study in mice we know that when you reduce calorie and mice by 20 to 40 percent then this my mice typically live longer than those who eat normal food and within a reasonable nutrition quality but the question so but there was a caveat to all the calorie restriction studies done in mice that is not clearly mentioned in many of the studies that is in Kerala restriction studies usually the mice that are put on calorie restriction they are given 20 to 40 percent less calorie but only one meal and mice usually finish that meal within three to four hours and in many cases they can finish it in within two hours so that means that eating within two hours to two to four hours and fasting for 20 to 22 hours wow every single day whereas the unlimited the control group has access to Healthy nutrition throughout 24 hours so now the question was whether the life extends an effect of caloric restriction is due to calorie restriction or due to Long fasting or how do we disentangle these two so this is a study that's very well thought out and well planned it also needed some technological advances where food can be delivered to mice at any specific time and in specific quantities so they had the control group that had access to food anytime and then the caloric restriction group was divided into multiple groups one group got only calorie restriction and no fasting so that means the reduced calorie food was even split into very tiny pellets and this mice got those tiny pellets in every two hours so if they're in a long eating window so yeah so in every two hours they're eating something they are not actually fasting much yeah they're just reducing calorie but no fasting um so compared to the control this group increase their lifespan by 10 percent which is pretty good I mean 10 likes for an expert extension in mice is very good so now the same calorie restriction restricted diet was given within 12 hours and when it was given within 12 hours so that means same number of meals but compressed into 12 hours so in every third every 60 minutes or so are these mice were getting a little bit of food but they're going through 12 hours of fasting and all this mice that it within 12 hours they got another 10 percent lifespan extension on the top of the other side on the top of 10 so now they're living 20 percent longer by combining calorie restriction and some time restriction so now even they went one step further they met that 12 hours fasting during day time when mice are supposed to fast because mice are nocturnal or night time so that means these mice were eating during day time when they're not supposed to eat and the fasting during night so the mice that fasted during night time so that is eating at the wrong time kind of relaxation so those are the ones that extended life's one by 20 percent but the mice that it at night time and faster during the daytime they actually live 35 percent longer okay so now they went one step further they said okay so what if we give all the food within two hours versus 12 hours and the increase in lifespan was negligible it was less than one percent right okay so whether it was 35 versus 36 percent or 25 percent versus 26 percent so the bottom line is at least in mice reducing the eating interval to two hours or three hours did not give too much benefit in terms of lifespan and they went to see the cause of death because at the end anyways the mystery dying the cause of death was not different among any of these groups they all died of the same causes which was mostly different types of cancer in this particular set of mice so at least the mouse experiment has given us one answer that whether we are reducing calorie or eating whatever you're eating any duration of fasting is better than no fasting but if you want to optimize then it's better to eat within your active period for humans it will be finishing your dinner by six or seven pm and that will give you the best benefit by the same time we have to keep in mind that in the pursuit of perfection we should not forget that what is practical and what suits your life you should try to do that yeah I mean thank you that is so beautifully explained because there's a real practicality there yeah you know there's Optimum yeah you know for the biohackers who who want to optimize everything great it's good to know that yeah but for a lot of people who just want yeah to lose a bit of weight more energy better gut function yeah live longer short whatever yeah it's like well look increasing the amount of time where your body is not consuming Foods for most of us it's probably going to be a good thing and have multiple benefits yeah because the truth is you know some people will say they've gone to one meal a day and they're thriving yeah and I don't think you would say to them don't do that or would you my only advice will be make sure that you have a balanced diet yeah because if you are eating only that one meal and you are not mixing the right proportion of micronutrients and micronutrients then yeah and again it depends what your starting point says you know are you someone who's carrying a lot of excess weight has got a lot of problems and then maybe you're thriving on this yeah and I think there is a Nuance there that we have to figure out and you know one of the criticisms I think that would be leveled at this in time movement is that well a lot of the studies and I guess this was more relevant a few years ago a lot of the studies are done in mice yeah what's the relevance to humans as someone who's literally at the Forefront of This research what do you say to those people I guess even in the beginning when I used to give scientific talks people used to tell me the same thing maybe it relates to mice and in fact um for the first few years I was never funded I didn't get any federal funding because the reviewers are my grant made that comment that you know this may relate to mice and we know that humans don't eat like mice so it may not have any significance so that actually forced me to go back and ask when people need and this was a very simple question that had never been asked objectively so we met this up my security and clock and where people had to just take pictures of that food didn't have to enter what they did didn't have to type in anything and or the first generation of that app and that's when we figured out we found that nearly 50 percent of adults in the US who are not even shift workers they were eating for 14 hours 45 minutes we rounded up to 15 hours and say that 50 percent of adults eat for 15 hours or longer that's when many human studies started and the question was can people who are already eating at 15 or 16 hours change their behavior and try to eat within 10 hours because I can come up with a discovery that eating XYZ for example maybe avocado with tomato every single day is good for everybody but people may not change their behavior so that was a big question can people change behavior and what we found was yes it was possible people could change behavior and there are some positive feedback loops so for example the gut health the sense of energy and sleep within those three actually drive people to sustain this behavior and then there are a lot of small studies and these are this is the way translation works exactly you go from mice and then you do small feasibility study to see whether it's feasible any humans in humans and these are typically small because you don't want to put too many people at risk by doing something that can even cause harm um so that first phase went through um the different types of studies and also it was gratifying to see studies were done in U.S Europe Asia and Australia in all this continents small group male and female younger and older people with obesity or diabetes or metabolic syndrome and Universal in most of the studies we saw benefit and these studies are also important because they Define what benefit we are going to see and what is the magnitude so that when you design large randomized control study then you can power them appropriately yeah so now we are going through that phase where there are large randomized control studies that are being done and also results are coming out but there is one thing that we have to keep in mind that in any nutrition intervention study if you are going to change something then you should be able to monitor whether people are making that change and when you're doing small studies it's easier because uh you have handful of people maybe 20 or 30 people and you can monitor when they're eating and you can also teach them how to comply with the with the intervention but when you go to large study that's the challenge can you actually monitor when people are eating and if you cannot monitor then it becomes very difficult to interpret the results the second thing is we know that people with obesity diabetes and all this metabolic disease they have adopted a lifestyle or habit that suits them and they're used to eating over a long period of time so they need extra support they're not they they're not the bleeding as biohackers who are ready to do anything and can take little bit of discomfort and so you need some support education and you have to do that in large trial and that can become difficult so that's why we have to we have to keep those in mind now ah those eating pattern monitored objectively and whether they were given the right type of support to adopt to this time restorating or intermittent fasting well one of the things I'd love in your um your license board the Circadian diabetes is a that's a step-by-step plan and you go through common problems people have whether it's headaches or compliance or energy and how they can deal with that which I think is really really helpful and you know although the title of the book is the Circadian diabetes code as I read it it's like well this book will help you whether you have diabetes or not it's a good recipe for how to live your life yeah um and something I'm passionate about as a medical doctor and I wonder about your view on this given that you're a scientist science has always interested me but I never felt enslaved by the science that I've always used as a way of guiding me rather than telling me exactly what I should do with my patients so my real life experience of time restricted eating probably since 2015 2014 is probably the sort of time when I started to implement it based on your really mouthfulness yeah but as a daughter it's like okay well let's be intelligent about this what is the likelihood of harm here by asking one of my patients to only eat within 12 hours or 11 hours or 10 hours it doesn't appear to be like much risk of harm here particularly if they're not on any medications or anything right so I think okay very very low risk of harm high potential for huge benefits okay I'm okay with that sort of risk benefit ratio and I would you know counsel people and I saw like your researchers now show like the human studies are starting to show but I have seen with hundreds maybe thousands of patients that when people compress their reaching windows and I I agree 10 hours I think it's a very sustainable and achievable window for most people you see benefits across the board yeah weight loss blood sugar energy Sleep Quality for IBS serious for bowel syndrome yeah oh man this is a big one for me yeah like they've got function just starts and almost all the IBS stuff out there tends to be about oh this diet or avoid these Foods or these Foods I get it but for me the two big things in IBS that I deal with before anything else are stress yeah and eating Windows because I find you if you go for those Upstream levers there are lots of Downstream benefits so I'm I'm a passionate advocate of your work and I've been using it with real life people including in my BBC One show in 2015 I used eating with a family huge benefits yeah they all did it together as well which is really lovely so I just wanted to share that because I know sometimes people go mice be human I think the human studies are coming but that's my real life experience yeah um but I guess going back to your comment about David Discord the reason why uh I wrote about diabetes is almost everybody knows someone either a close friend or a family relative um or even within the same family or maybe the same person who may be pre-diabetic or has Type 2 diabetes that's true and we don't take it seriously because it's not like a heart attack or heart failure or another stuff but we know that diabetes is the entryway to heart disease living with diabetes is almost like living with having experienced at least one heart attack yeah so that's why and also now this starts is nearly half of the adults in the U.S are either pre-diabetic or type 2 diabetic yeah and just like you said we have barriers to good lifestyle and one of the barriers can be being around with family members who want to have late night dinner or eating anytime so so that's why the book is actually for everybody because if you don't have diabetes at least you are caring for somebody who has diabetes and the best gift that you can do right now is to help that other person to live a healthy lifestyle by paying attention to cicadian Rhythm um eating compressing it in window paying attention to sleep and then a little bit of attention to exercise and light yeah and just to clarify when we say diabetes of course we're talking about type 2 diabetes as opposed to type one just to finish off uh Sachin there's three areas I wonder if we could just briefly touch on shift work naps and jet lag um one of the things that struck me yesterday when I text you and I know you've only within the last couple of days landed from America which of course is you know you're on the west coast so there's an eight hour time difference between what your body clock is used to and what we're on in the UK and of course we've been trying to juggle the time of this conversation right and I remember texting you yesterday saying are you sure 8 A.M is not too early for you because I'm aware that that's like midnight for your body clock yeah um won't you be jet lagged and you said something like no I'm not suffering from jet lag I was like okay that's interesting because I'm someone who is very much struggled so why are you not suffering from jet lag and what a in your view what are the key things that we can do to reduce the likelihood that we're going to be flawed by it yes a jet lag is when your brain clock is still thinking you are in the old time zone and your body clock is also thinking in a different time zone so essentially your clocks are desynchronized from whatever time zone you are in and as we have learned that light resets our brain clock and food research or the rest of the body clock then we can use that to reset ourselves to the new time zone so that means uh when I travel U.S to Europe most of the flights live U.S in the evening or late afternoon and reach Europe in the morning so that means that should be the usual fasting time for everybody so no food in flight so you don't eat on the flights yeah no food in flight and if it is short flight like this was a short flight for me because it was maximum eight hours flying so that means even I had to finish my dinner our last meal before even boarding the plan and then in Flight is to not get too much light exposure so that means the only thing that it should be doing in Flight is trying to sleep so I not only try to sleep I actually carry a eye mask or sleeping mask so that really cut out all the light exposure um so no watching television and not even very little or minimal reading only books or something with light following on his book and trying to sleep and then after I reached here again the flight reaches at 6 45 or 7 in the morning by the time you check into the hotel it's 8 30 or 9 so your breakfast um is around 10 o'clock in the morning so I already had a long fasting followed by this very nice big breakfast that tree set up my body clock and so food can do that it can just it can help literally reset your body clock and then of course I had a long drive from the airport to the hotel and as I said even if you're just looking outside it was a it was a rainy day in London but still that much light is enough to keep me awake and reset so so basically you're paying attention to lights and Foods to help you when you come this way and I guess when you go back from the UK to the US the flight will probably be in the daytime the morning or lunch time from here yeah I've done that many times in the past not for the last two or three years having said that but it's almost the op well would you eat on the plane this time when you go back yeah so this time I'll eat my meal in plan but then when I learned since I'm landing in the evening I actually don't need that evening meal so I can go to the next morning and that would give me that long fast followed by the breakfast next morning but whatever you do is working because two days into your trip having no jet lag and doing an early conversation with me where you're sounding completely on your game uh I think just speaks to the power of what you're doing that's jet lag can we just briefly because we set at the start there's Optimum but the reality is many people they go yeah that sounds great but I'm a shift worker or I have to work late into the evening are there any tips I can use and I know in your books you've written about many tips for Chef workers which is super helpful can you just give us a sort of brief overview on the sorts of things that shift workers can do to help them yeah so unfortunately shift work comes in many different flavors different types of shift and how they change the shift we have specifically worked on one type of ship drug that's 24 hour ships that firefighters do in the US I don't know about 24-hour shift in UK and in our study which hopefully will come out this year what we found is firefighters should do 24-hour shift they could adapt to 10 hours time restorating with and we asked them to self-select that 10 hours and what we found is most of the firefighters they selected a daytime time restricting window that ended somewhere between seven and nine PM so they could all eat during day time this is when they're on for 24 hours 24 hours but they still had enough energy to go through the overnight calls and this was risky for the fire department and also for us because we thought well if they cannot do their job this is a civic duty this is Civic safety it's not only for their own safety they cannot respond to a fire if they cannot respond to an accident that that's actually too much risk for us and we're pleasantly surprised that they could actually do that and um during that time we also found out that they felt that by not eating during their shift they felt more light and full of energy when they responded to the call wow and when they came back from the call they could actually go back to sleep much quicker and on the off days they could maintain that sleep and they could get the recovery slip much better so that was surprising so now going back to other shifts 12 hour shifts or eight hour shifts of course this is challenging because if they are changing their shift too frequently then um it will become a challenge but we have also seen other shift workers where this shift changes once every two months or three months and typically what they do is they try to align the eating with their shift um so that when they're not on the shift work they can have enough sleep and fasting combined so that they can benefit so if you're let's say you're a nurse or adults are on a night shift um and you're doing let's say an 8 00 p.m till 8 A.M or something like that you might try and encourage them to eat during that time winner even though it's the night yeah so uh there is a caveat when they're doing uh this 12 hours shift at night and doctors and nurses they usually have I don't know in the UK but in the US nurses typically have four days a week they don't actually work all seven days four or four okay yeah yeah because they're doing 12 hours four days they're getting 48 hours almost so in those cases um this is again what I call a net data because we haven't done clinical trials but what we have seen is what nurses can adapt to what they can do is they try to have a eating window that starts from say noon or two o'clock and then goes till 10 o'clock at night um so in that way they can maintain that same eating window on the on days and off days yeah I get it so that's really yeah it's really clever isn't it so you're not switching too much yeah so they keep that same meeting window and it's again personal so they can find their own sweet spot but the same time when they come off the shift in the morning if they're driving then they still need that black coffee or black tea to make sure that they are safe for their driving safe and it can interfere with their sleep so that's something that they have to work on um to see whether they can just have a warm decaffeinated tea or something just to get them home or if they're taking public transport actually the good thing in the UK is people can take public transport that don't need to be caffeinated and they can get home and get that restaurant yeah that's super helpful uh just finally then naps yeah um in looking at circadian biology and how important a robust circadian biology is for you know everything we've spoken about you know weights touched our BCS inflammation but also mood you know depression these sort of things absolutely really important to have a good circadian rhythm um in your view can naps help us if we need them yeah actually if we go back to human his the history of humans on this planet and we are not fully diurnal what we call we are crepuscular so that means we are more active in the morning and evening and we're designed to be uh to take a nap after lunch yeah so um early afternoon right afternoon so so that's when if you think about it although we have access to now air conditioning and cooling but our ancestors didn't have that access so it is to be very hard to go outside outdoor and for most of the human history only in the last 35 000 years humans moved away from the equator to go north or south but equator that area I used to be pretty hard so we are designed to take the nap early afternoon nap so so it's it's already imprint traditional you know today I mean you know for me I'm a fan of naps yeah I appreciate you know for many of our jobs we're unable to but certainly at weekends yeah man I love a nap yeah I would get up early but I also like a an early afternoon post lunch nap and I guess culturally I grew up with seeing my dad doing it you know and so it's kind of or when we'd go to India every other summer I'd see my family take naps after lunch so I kind of it's ingrained in me um and if it's early enough and I I've been recommending the apps I know there's a lot of controversy around naps I personally find that as long as an app isn't taking too late where it can impact the evening yeah I think that can be incredibly helpful and there's a ton of Science Now on what it does for a concentration Focus learning creativity yeah those kind of things so you're you're Pro naps basically yeah I mean we're designed for naps yeah and of course what I just said we should not take it too late yeah no napping after 3 P.M or 4 P.M um Sachin I've I've just so enjoyed chatting with you um you know you're involved with science and you have been for many years now that is changing the fabric of how many people live their lives you know yes I've also preferred the term time restricted easing but it is commonly adopted as intermittent fasting right yeah because I've always found intimacy confusing as a term I thought what does it mean whereas time said eating for me made it was very clear it's like you know you restrict your eating window you eat within this period of time but the truth is you and now many other Sciences also of course are are helping but you and your lab has been really a big player in putting this on the map a way of living and eating but many people around the world are trying I want to acknowledge you for that thank you I always find you very humble with your research in terms of what you've done um but but I think it is really really impactful and you know I could sit here for another two hours and chat to you about so many other things but you know we've got to we've got to call that close at some point um the books are brilliant I think the book's going to help a load of people this podcast is called feel better live more when we feel better in ourselves we get more out of life just at the end here now for people who feel inspired by what you say to think yeah you know what I think I think I want to give this a try do you have any final kind of top tips to share with people to leave them with so they can take your work and use it to improve the quality of their lives yeah so there are six ticks okay love it okay so number one uh go to bed at consistent time and try to be in bed for eight hours so that you can get seven hours of sleep and then number two in the morning um wait for at least an hour after waking up because that's the changing of the guards the night hormones are going down the day hormones are coming up and your body is not ready to digest and a similar nutrient the number three is to have again consistent time for breakfast and then eat for the next eight 9 10 or maximum 12 hours not beyond that then number four is try to be outdoor for at least 30 minutes under daylight even if it's a cloudy day because light synchronizes our brain clock it's a antidepressant it reduces sleepiness improve our executive function anytime in the day or specifically the morning if you can do in the morning that's better if you can do any other time of the day then that's also good okay um so then number five is exercise physical activity if you're compressed for time then afternoon physical activity is much better than any other time of the day because that's when your muscles are ready your flexibility is better and so your risk for injury is low and afternoon exercise is much better in reducing blood glucose than morning exercise of same time and duration and then number six is two to three hours before bedtime it's again changing of the guards the day hormones are going down and the night hormones are coming up so for two to three hours before bedtime no food and no bright light so those are the six super simple you've explained all the science uh it's just been wonderful chatting to you thank you so much and um maybe in a few years again we can revisit this to see where we're up today with the research thank you so much thank you I will do if you enjoyed that conversation I think you are really going to enjoy this one about the daily things you can do to lose weight and prevent disease I used to think you know weight loss is just about willpower it's about calories in calories out the energy balance equation is always true but people always misinterpret it to mean that just eating fewer calories leads to body fat loss it does not

Channel: Dr Rangan Chatterjee

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Keywords: the4pillarplan, thestresssolution, feelbetterin5, wellness, drchatterjee, feelbetterlivemore, ranganchatterjee, 4pillars, drchatterjee podcast, health tips, nutrition tips, health hacks, live longer, age in reverse, self help, self improvement, self development, personal development, motivation, inspiration, health interview

Id: wPwvATBw7HI

Length: 124min 1sec (7441 seconds)

Published: Wed Oct 26 2022