0:00 What was it that they ate that day that impacted how they slept that night? And we found that higher intakes of fiber were associated with more deep sleep, higher intakes of saturated fat, less deep sleep, and then more refined carbohydrates, simple sugars, more arousals. You're not getting deep slow-wave sleep, REM sleep as much as you would otherwise. >> Welcome to the Huberman Lab Podcast, where we discuss science and [music] science-based tools for everyday life. I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. My guest today is Dr. Marie-Pierre St-Onge, a professor of nutritional medicine at the
0:46 Institute of Human Nutrition at Columbia University School of Medicine. Today we discuss how you eat impacts your sleep, and how you sleep impacts what you eat, as well as how your body utilizes food depending on how you slept. Now, we've talked about food, and we've talked about sleep many times before on this podcast, but Dr. St-Onge's work is unique because she runs one of the few laboratories in the world to look at the bidirectional relationship between sleep and food. For instance, you'll learn how even modest sleep deprivation increases hunger, but differently in men and women. In men, it happens to increase the hormones that drive the desire to eat, whereas in women, it reduces naturally made peptides such as GLP, which suppress hunger. Today's discussion gets into the specific actionable items that you can
1:31 do to improve your sleep and the way that your body handles food and hunger. We talk about the role of sleep in regulating blood sugar, cortisol levels, overall metabolism, and cardiometabolic health. Now, because Dr. St-Onge's research focuses on sleep and nutrition, but she's also spent a significant amount of time studying how specific nutrients impact overall health and not just sleep, we also talk about that. I'm certain that you'll come away from today's episode with a lot of new information you haven't heard elsewhere, as well as with the intention to make small or perhaps even large changes in behavior and nutritional choices that the science tell us can significantly improve your sleep, your metabolism, and overall health. Before we begin, I'd like to emphasize that this podcast is separate from my teaching and research roles at Stanford. It is, however, part of my desire and effort to bring
2:17 zero-cost to consumer information about science and science-related tools to the general public. In keeping with that theme, today's episode does include sponsors. And now for my discussion with Dr. Marie-Pierre St-Onge. Dr. Marie-Pierre St-Onge, welcome. >> Thank you for having me. >> Sleep impacts how and what we eat and how and what we eat impacts sleep. That's a different perspective than I think most people take. I think most people are familiar, however, with not getting the best night's sleep, maybe feeling like their impulsivity to eat quote-unquote bad foods is a little higher, and then also hopefully familiar with having a great night's sleep and feeling like we're just kind of in control in a different way. Maybe you could just kind of share for us what's really going on beneath that
3:03 experience and when subtle or not-so-subtle chronic sleep loss, so not an all-nighter necessarily, but you know, 45 minutes less here, 90 minutes less there, etc., etc., how that plays out in terms of our nutrition, and then we'll go in from the nutrition side to sleep. >> Sure. So, there's a couple of questions that you have in there, actually, about the extent of sleep loss and how that influences your food intake, what we see in the general population versus what we do in the lab to address causality. So, let me start with, you know, the population-based studies, right? So, when I started being interested in in sleep, it was coming from an obesity
3:48 angle. My PhD is in nutrition. I trained as a postdoc in body composition, obesity research. And we were getting a lot of information from population-based studies that people who sleep too little have a higher body mass index than people who get adequate amount of sleep. Then it became there is a higher prevalence of people with obesity in this short sleep uh group. Then studies evaluating changes over time seeing that people who don't sleep enough tend to gain more weight. There was a famous uh Nurses' Health Study that I really like to cite uh when I give talks that was published in 2006
4:35 where uh they tracked nurses over 14 years and those nurses that reported sleeping 5-6 hours had much higher rate of weight gain over that 14-15 year period than the nurses who had reported sleeping 7 or 8 hours per night. So those are observations that we get from large-scale population studies, cohorts. But, you know, what they what those studies tell us is that things are happening at a point in time or may influence something that's happening over time, but not necessarily that one causes the other, right? So I started um my work in this field trying to uncover whether sleeping too little actually causes
5:23 weight gain. And so in my opinion, because I was coming from a lab where I trained in the measurement of energy balance, so how much energy how much energy you eat versus how much energy you burn, I was like, well, if sleep leads to obesity, leads to weight gain, it has to impact this energy balance regulation. So it's either that we eat more than we should or that we exercise less. We burn less or we eat more or maybe it's a combination of the two. Let's try this out and and see. So my first my first study my first NIH grant the big R01s, you know, was to look at exactly at this. So we had
6:09 people who had adequate sleep and we brought them in the lab and we asked them in a crossover design. So half of the participants started out sleeping adequately. So they we gave them a 9-hour time in bed opportunity or we asked them to sleep too little. So they had a 4-hour time in bed opportunity, very short. But we did this for 5 nights. And then we took all sorts of measurements in a controlled feeding condition. So for the first 3 days, we told our we had our participants eat the exact same thing regardless of how much time in bed they slept they got at night. And then we measured appetite regulating hormones. We did neuroimaging uh to really get at isolating the impact
6:57 of sleep duration on appetite regulating hormones and and um neuronal responses to foods. And then on the last day, we let them self-select their food intake and we measured that in the lab. From that study, we showed that in men specifically, uh we saw an increase in ghrelin in response to the short sleep. So this hormone that triggers food intake. In women, we saw a reduction in GLP-1, interestingly enough. Glucagon-like peptide-1. So the satiety hormone was reduced as a result of short sleep in women. And then when we measured their food intake in the lab, they ate 300 calories more in the short sleep condition than the
7:43 when they got their regular adequate sleep of at least 7 and 1/2 hours, a little more than that per night. Then you were asking about, you know, brain responses. We looked at neuronal responses to food stimuli. We found upregulation in reward centers of the brain in the context of sleep restriction compared to the context of adequate sleep. So all together really building a case that when you don't sleep enough at night, you have both physiological signals to eat more for men or not stop eating in women that lead to greater food intake that's also could be impacted by
8:29 just pleasurable centers that are activated to a greater extent as a result of insufficient sleep. >> Amazing. This sex-specific split in the data, if I have it correctly, that when men are sleep-deprived, so getting 4 hours per night, the signals that drive appetitive desire to eat are higher. In women, it's more that the break on eating, on satiety, is reduced. >> Exactly. >> Okay. As far as I know, the GLP pathways are not divergent by by sex, but of course I'm not deeply versed in that literature. Is there any evidence that GLPs are functioning different in men and women like circadian wise or anything like that or this just this was just a fortuitous outcome or as I say a
9:15 incidental outcome? >> This was an incidental outcome. We really didn't know what to expect. We didn't really know at all that we'd see sex differences >> Mhm. >> because there had been prior studies and prior studies had shown that ghrelin was increased as a result of sleep restriction. They also showed that leptin was reduced as a result of sleep restriction. And when we got our data, we analyzed our data with all of our participants together. And there was no effect. >> [clears throat] >> And that was surprising, and people would say, "Don't you know? Don't you know sleep restriction increases ghrelin?" Like, "Well, I guess I don't know because in our study it doesn't." But
10:01 then we saw these sex-specific differences, and it made sense then that in the full sample, when we had an equal number of men and women, we saw no effect on ghrelin because there was no effect in women, but there was an effect in men, which was reproducing what others had found because all the prior studies had been done in men only. >> I'd like to take a quick break to acknowledge one of our sponsors, David. David makes protein bars unlike any other. Their newest bar, the bronze bar, has 20 g of protein, only 150 calories, and 0 g of sugar. I have to say, these are the best-tasting protein bars I've ever had, and I've tried a lot of protein bars over the years. These new David bars have a marshmallow base, and they're covered in chocolate coating, and they're absolutely incredible. I, of
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11:34 to get the fifth carton for free, go to davidprotein.com/huberman. Today's episode is also brought to us by BetterHelp. BetterHelp offers professional therapy with a licensed therapist carried out entirely online. Now, I've been doing therapy for a very long time, and I can tell you that it's a lot like physical workouts. There are days when I want to do it, and there are days when I don't want to do it. But, when I finish a therapy session, every single time I come away feeling better and knowing that the time was well spent. There's just so many benefits that come through effective therapy. Now, with BetterHelp, they make it very easy to find an expert therapist who can help provide the benefits that come from effective therapy. You fill out a short questionnaire to match you to a therapist, and while BetterHelp has an industry-leading match rate, if you aren't happy with your match, you can switch to a different therapist at any
12:19 time. And it works. BetterHelp has an average rating of 4.9 out of five for its live sessions based on over 1.7 million client reviews. If you would like to try BetterHelp, go to betterhelp.com/huberman to get 10% off your first month. Again, that's betterhelp.com/huberman. Whenever I'm sleep deprived, though four or five hours of sleep I consider sleep deprived. I used to pull all-nighters years ago. Now, I avoid them at all costs. But, whenever I have that experience, I feel like my whole body to some extent is in a low level of pain. It's a kind of it's like central ache. Like you just And and I wonder uh extent to which people eat to overcome like to kind of quell the the pain of
13:05 sleep deprivation. Maybe people react differently to sleep deprivation. Maybe their subjective experience of it is is very different. But, what do you think is happening in that uh in that short relatively short amount of sleep that's missing? What is getting reset? Is it neural? Is it endocrine? It's obviously all those things, but what do you think is the the switch that allows people to enter a a day in a in a much more healthy fashion or or a sick essentially in a slightly sick fashion. >> In our study, it was actually a 50% reduction in sleep because when they had 9 hours sleep opportunity, they slept around 7 and 1/2. And when they had the They were all people who had screened to sleep at least 7 measured by actigraphy. So, and on average they get 7 and 1/2.
13:50 And in the sleep restricted condition, they got on average about 3 hours and 50 minutes. >> So, it's like staying up late working on a deadline then trying to catch an early flight. >> Yeah. >> brutal. >> It's pretty brutal. Yeah. And that was maintained, you know, they had 5 nights of that. So, that >> 5 nights of that. >> Yeah. >> Were they coming unglued mentally, too? That I think I would feel terrible after that kind of stretch. >> That Yeah, they were done. Like there's no way anyone would want to keep keep coming for that. But they were in the lab. They were under supervision the whole time. We didn't let them go out on their own. Uh so, they were well supervised to make sure that nothing nothing would happen to them. >> No naps? >> No naps. Nope. Nope. Uh but so, what happens is I think there's some
14:35 subconscious need to to eat more when you're sleep deprived. There's also, you know, there's a thermic effect of of food, right? So, it gives you a jolt of energy to eat something. So, people know that. You eat it wakes you up in a way. You know, neuronal signaling that that enhances uh pleasurable and reward centers of the brain where, you know, if when also fatigue sets in and now it's like do you really have want to have this conversation with yourself about what to choose at the buffet table? You know, it there's fatigue. And uh and others have shown also that sleepiness tends to correlate with all of this. That there's these triggers for more pleasurable food
15:21 consumption with um with the sleep restriction. It's been reproduced. There's been so many studies and they all you know, agree to to the extent of overeating. You know, a meta-analysis showed 250 to 400 calories of overeating. >> Which might not sound like much, but when you start layering that in day after day and you think, you know, 3,500 excess calories more or less for a pound of body weight and then you start when people accumulate that over time if they're in a night shift condition or new parents or tending to a sick relative or just final exams. Like it it's a real thing. >> It's a real thing. Naima Covassin in 2022 published a paper where they had sleep restriction about 5 hours per night versus 7 and 1/2 hours per
16:08 night for 2 weeks and participants gained half a kilo in a 2-week period. So, you do nothing and you just you know, sleep less and gain gain almost a pound in 2 weeks. >> It strikes me that, you know, for a long time in the stress research, the idea was when people are stressed they reach for kind of quote unquote comfort foods, carbohydrate and typically starch fat, starch fat sugar combination foods to comfort them and and the the just-so story was always that okay, well, you know, cortisol's main role is to deploy glucose and so people are doing this as a way to bring excess energy and and it all kind of fits together. What is the relationship between these forms of sleep deprivation that you work on and stress? Is it really a way of of I'm not saying just
16:54 inducing stress cuz I think sleep is its own thing, but it's stressful just to be less than adequately rested independent of the things coming at you in life, right? Is what you're studying stress? >> So, if you're thinking about physiological stress measured by cortisol levels in that study, actually cortisol wasn't changed. >> In the short sleep. >> in the >> sleep. >> Tell me more about that. I'm fascinated by circadian rhythms and cortisol. So, what is it what is that what is that mean? >> There was no difference between the two conditions adequate sleep or short sleep on cortisol levels in our >> For 5 days of sleep restriction at basically 4 hours a night. So, cortisol still peaking in the in the morning, still dropping in the evening. >> Yeah. >> Wow, that's very surprising to me. >> I don't know. I don't know if it's the contacts of, you know, being in the lab
17:42 where everything's safe, taken care of for them. There's nothing outside to aggravate >> Mhm. >> this. [clears throat] So, I don't know. Maybe when you're in the context of sleep restriction, but also dealing with your daily life >> Mhm. >> you're needing to take care of your kids, they're needing to get to work, needing to do all of the activities of daily living, maybe then that becomes, you know, the the added stressful. >> So, the message is if you suffer less than adequate sleep, get someone to take care of it. >> Everything else. >> You better be [laughter] in a spa. >> Exactly. Exactly. >> [clears throat] >> No, I and I'm not challenging the result. I just find it really interesting. I would have thought that basal cortisol levels would would go awry. >> Well, in that study also, we didn't see any effect on glucose or insulin.
18:29 Nothing. The curves were superimposable. >> Wild. >> They were eating the exact same food at the exact same time, exact same quantity. The only thing we changed was the amount of sleep opportunity they got at night. So, to me, this means that it's a combination of different things that causes the metabolic abnormalities that we notice in free-living populations. People aren't isolated, they're not in a box where they're not sleeping enough, and they're choosing to eat higher-fat, higher-sugar, higher-salt poorer diet that then triggers a worsening and maybe compounded by the lack of sleep even
19:16 worsening of of those cardiometabolic outcomes because we did a follow-up study to this this severe sleep restriction study. So the reason why we did that was because exactly for this reason because we did not find any adverse impact on glucose or insulin or lipid profile. And we're like so what is it then? Why is it that in population-based studies we find that people who sleep too little have higher risk of cardiovascular disease, higher risk of hypertension, higher blood pressure, higher risk of type 2 diabetes. So because we had seen that food choices were different that they ate a diet that was higher in calories, higher in fat and saturated fat, we thought
20:02 maybe if you're in a free-living situation that's when you start to see those cardiometabolic outcomes because it's compounded by maybe more sedentary behavior and alterations in in food choices and and diet. So the follow-up study then was to recruit good sleepers, people who sleep at least 7 hours per night verified by actigraphy, who answer on questionnaires that their sleep quality is good. And then to take these people and say okay now you're either going to continue your excellent sleep or you're going to now go to bed an hour and a half later so
20:50 that you get an hour and a half reduction in sleep. Because when we screen people to sleep at least 7 hours per night, they sleep about 7 and a half. And reducing by an hour and a half gets to 6 hours which is short sleep, insufficient on average what people who don't get enough sleep get? >> They're missing a full sleep cycle. >> Yeah, pretty much. And uh and they can sustain that for prolonged periods because that's what people report in in population-based studies. And now, when we did that, we saw that insulin resistance was increased after 6 weeks of sleep restriction compared to adequate sleep. We saw insulin sensitivity was reduced. It was worse, actually, in
21:35 postmenopausal women compared to premenopausal women. We saw blood pressure uh was increased. Uh so, those cardiometabolic outcomes were adversely impacted in free-living mild sustained sleep restriction for 6 weeks. 6 weeks was something else, also. >> [laughter] >> It was uh it was tough. >> I can only imagine. Wow, okay. Because my mind always goes to, all right, well, we wake up in the morning because of an increase in cortisol, that's circadian, and it's not related to sleep, per se, it just kind of overlaps with the end of the night's sleep. If that's independent of sleep, and cortisol drives glucose release, we know this. At least in the first study you described, glucose levels weren't altered. You said it was isocaloric, so
22:20 people were it's not like they're eating more. They're the hormones that are driving the desire to eat more are elevated. >> But we didn't let them eat more, yeah. >> Right. But you didn't let them. I think that's a a key thing that you you pointed out before, but I think we want to uh underscore. And then, of course, the GLP uh levels in women being reduced, it's not that that they were able to eat, as we say, ad libitum, and then they happen to eat more, but they gained weight. So, what's kind of the action end of things that causes them to gain weight if they're basically in an isocaloric diet? And I have a I have a I have an idea what it might be, but I'm I'm curious what the answer is. >> Yes, I think they're they're more sedentary. >> During the day, less >> Right. >> Less spontaneous activity. Because we
23:05 also did a study to look at energy expenditure. That's really difficult actually to measure, in my opinion, energy expenditure. There's multiple components to energy expenditure. Uh but we did a study where this was a small study. We were enrolled only women for that, and we have a metabolic chamber >> [snorts] >> at Columbia where that we were able to use for this. Uh so this small room in which we keep people, and we measure minute by minute oxygen consumption and carbon dioxide production. And we were able to show that energy expenditure is actually increased in the context of sleep restriction in the metabolic chamber. >> [snorts] >> Because it's more costly energetically to remain
23:51 awake than to fall asleep. So energy expenditure when participants were awake was identical in both [clears throat] conditions, regardless of how much sleep they got the night before. >> So is fidgeting, movement? Cuz we've talked before on this podcast about the non-exercise thermogenesis. It's a big number. I mean, you people who fidget a lot, bounce their knee a lot. I mean, sometimes these people are burning 1,500 calories more per day. And everyone goes, "Oh my god, how could that possibly be?" But I mean, that's a lot. That's at the extreme. But it is kind of interesting to observe people out in the world. And you sometimes see that people who are very, very lean, very let's just say thin and lean. Nowadays, who knows because of the GLPs, etc. But they tend to have a lot of spontaneous movement. They tend to stand up quickly. They tend
24:37 to walk quickly. Well, you're from New York, so everyone there walks faster than out here. But it's a real thing, you know? Whereas some people, like me, are kind of more middle of the curve. But you know, I sit a bit more still unless I'm very caffeinated. These things add up over time in ways that I think most people underestimate. >> Yeah, so for us it was about 5% of energy increased. But it it and it it ended up being about 90 calories, nowhere close to the 300 calories that uh more of intake they they got over a over a day in the prior study. So it's still an imbalance towards a positive energy balance when we do the math. But there is an increase in um in energy expenditure. Again, in the confines of metabolic
25:23 chamber, which you know, for most people is the equivalent of the size of their bathroom. >> Right. >> Right? Where you have like a bed, a table, and a sink, a toilet, that's it. So you can't can't do much in there. >> But you can do studies, quote unquote, out in the wild with um actometry or what or uh >> Yeah, digraphy, doubly labeled water. Yes. >> A little while ago I saw a study that said that if you are one night sleep deprived, like you get one or two hours less uh sleep than normally you would get to feel rested, that it's actually advantageous to exercise because it offsets some of the um increase in inflammation. >> Mhm. >> But then if you're going multiple nights that way, exercising on a regular basis when sleep deprived, it just sets up a um susceptibility to illness, susceptibility to injury, and so forth. How much of what you observe in the
26:10 under the conditions of sleep deprivation do you think are downstream or upstream of this thing that we just call inflammation? Like is this just like a body wide response and there are a bunch of things that have gone awry and and so like a bunch of systems are dysregulated or can we pinpoint, okay, when you're sleep deprived, this is what this is what's happening. Cuz I think if if women knew that their GLPs were down when they're down on sleep, so that they should expect that they would feel less satiety. If men knew that their ghrelin levels were elevated when they're down on sleep, that they're going to feel hun- hungrier. And we have a pretty big prefrontal cortex, most people anyway, and we can intervene simply on the basis of knowledge. >> I think that's what's empowering. And I think about this sometimes, too, when
26:57 I'm when I'm thinking about, you know, my my diet at times, right? I'm like, "I Do I really want to eat this or is it because I really didn't sleep last night?" Right? So, you can you can make you can ask yourself these questions. Take a pause and say, "Okay, do I really want, you know, dessert? Or is it just that I'm tired and, you know, I should just I'm fine. I don't need it." >> Mhm. [clears throat] >> So, if you if you step back and think that maybe part of it is because you didn't sleep well the night before, then you can make your appropriate choices, right? Say "Okay I probably don't need the the extra calories right now. Or or maybe you say, "You know what? I had a really bad night last night. And those extra calories,
27:43 I don't really care because they're going to make me feel good and I need some pick-me-up." But, you know, that's it Oh, that's all the choices to make, right? You know, because mood comes into comes into play, as well. So, >> Well, ultimately, that brings us to the the other direction of the equation, right? How does what we eat impact our sleep? This is something that I think most people have heard about in the context of try not to eat too close to bedtime. >> Mhm. >> Um this is an active debate in many households, actually. Some people seem to be fine eating close to bedtime and sleeping and even if they track their sleep. Other people, it really disrupts their sleep. I'm interested in both the timing of food intake relative to sleep, but also the content of the food and how
28:31 it impacts sleep. >> Mhm. >> What's known about that, either from your work or from other work? >> When we started this conversation, I was telling you about these population-based studies, you know, cross-sectional data where two things happen at the same time and you you know, you you don't really know causality. They happen at the same time, and I think early on in this field we started thinking about sleep as the promoter of food intake or as a sleep causing changes in diet, exercise, but didn't really think that maybe it's the other way around or maybe the other way around is just as plausible. So I started thinking about that and said, "Well, what if what if we took the other approach? What if we looked at
29:17 diet and examined how diet influenced future sleep?" And my first paper in this field was using data from the Multi-Ethnic Study of Atherosclerosis. It's actually kind of hard to find good cohorts that have good nutrition data, good sleep data, and data over over years, right? So MESA, Multi-Ethnic Study of Atherosclerosis, is one of those great cohorts that we have in the here in the US that has all of the above. So I paired up with a colleague of mine, Susan Redline in Boston, and she's principal investigator on their sleep ancillary study, and we asked the question of diet quality and its impact
30:04 on sleep duration, insomnia symptoms, and we found that having a diet that more closely aligns with the Mediterranean diet was associated with better probability of having adequate sleep and reduced insomnia symptoms in this cohort. So then it launched a whole field of study really to to keep looking at this, and we've looked at this in different studies and different cohorts. Actually, earlier this year we published data from the Women's Health Initiative, another large large cohort with good diet data and and sleep information. We took a really really nice approach in this longitudinal analysis. I don't know. Usually when we do longitudinal studies, we exclude people who have the condition
30:51 at baseline, right? So if you're trying to see this factor at baseline, how does it influence hypertension 10 years later? You usually exclude people who have hypertension at baseline because you want to see the development of hypertension. In this case, we're looking at insomnia symptoms, but insomnia is one of those conditions that's not necessarily static. It resolves, right? So you can have insomnia and then a few years later not have insomnia. Or you can not have insomnia now and develop insomnia. So what we did is we broke our down our participants into two groups. The people who had no insomnia at baseline
31:38 and at 3 years follow-up, participants who had insomnia at baseline but not at 3 years follow-up. So they were in the healthful sleep, improving sleep. And then the other group was all those women who had insomnia at baseline and at 3 years, and no insomnia at baseline but insomnia at 3 years. So they were the persistent insomnia, progressing towards poor sleep group. And we found that the women who had a diet that was more closely aligned to the Mediterranean diet, but we also looked at an American type of diet profile called the DASH diet, the Dietary Approaches to Stop Hypertension. Women who had a dietary profile closer to those two
32:24 types of diets, healthful diets, were less likely to have hypertension insomnia at 3 years. >> And the DASH diet is what? >> Dietary Approaches to Stop Hypertension developed to reduce prevent hypertension, reduce blood pressure in people by increasing intakes of fruits and vegetables, nuts and seeds, consuming low-fat dairy, more plant-based types of diet and and can be has been tested in a low salt or regular salt profile. >> How did those work out? I'm just curious. Do you recall if the low salt, high salt condition >> There's salt sensitivity, so there are some people who are very sensitive to salt and so having a reduced salt diet will really improve their blood pressure.
33:10 >> Mhm. >> Others not so much, but the DASH diet, regardless of its salt content, did better than the equivalent non-DASH. Which would be your average, you know, American diet. >> Whatever that is. >> Yeah, higher in saturated fats and sugars and >> Which seems to be changing now because of the GLPs. I feel like that's, you know, maybe that's a skewed perspective, but I feel like the the typical American diet is it might not be changing so much in content, but in volume it seems like people are eating less. Certainly the snack food companies, from what I understand, are struggling. Alcohol companies, that's a different issue, but that they're certainly have sales are way, way down, but it seems like people's appetites are down. >> Well, GLP-1s will do that, right? >> Yeah. >> And we were talking about this the other
33:55 day here, uh how many Americans have tried a GLP. The estimates are anywhere from like one in seven, some people say it's it's more. >> Mhm. >> pretty incredible. >> pretty high. >> But this is interesting. So, how people eat impacts their sleep, I'm sure the listeners and I also am thinking, okay, but people who are eating a Mediterranean diet, right? Olive oils, fish, you know, fruits, vegetables, they are probably more apt to walk more, exercise more, socialize more, all of How do you separate out the variables in a study like that? >> Uh well, so So population-based studies we adjust for a bunch of covariates, right? We have all these questionnaires that are given out to people asking them about their race, occupation, socio-demographic,
34:42 socioeconomic status, and then we adjust we adjust for um different illnesses that they may have, depression, uh physical activity level, uh So we try to take all this into into consideration. Obviously, we there's always unmeasured factors that you can't control for, social interactions like you um you mentioned. It's usually not captured very well. It's not something that we we can adjust for. But one thing that we did in my lab uh going back to that original study was to look at uh how diet influence sleep at night in the participants in our inpatient study. So we took
35:28 the 9-hour time in bed opportunity phase, only that one. >> [snorts] >> In the 4-hour time in bed opportunity, participants were very efficient. There was not much variability in sleep duration in in that phase. They slept as much as they could in that 4-hour opportunity. But in the 9 hours, there's variability there. Some people got more or less. So we wanted to see if food intake was related to their sleep at night. That study we had polysomnography assessments of sleep every single night. Like I mentioned, we had uh controlled diet initially, and then we let them self-select their food intake. So we took a very systematic approach to evaluating how diet could influence sleep in that study.
36:14 We said first of all was the diet that they chose different than the diet that we gave them. First step, right? It was. So they ate almost 450 calories more. They ate 33% more saturated fat. Uh little less protein, I believe, a little more carbohydrates. Not much, but it it was different. So, I was like, "Okay, so so there's difference between the diets." Okay, now, was their sleep at night different when they were eating the diet that we fed them compared to when they self-selected? And it did it was different. It wasn't different in terms of duration, but it was different in time it took them to fall asleep, which was
36:59 almost over 70% longer to fall asleep when they self-selected their diet. And their slow wave sleep, so deep sleep, was shorter. I think it was about 23 20% shorter when they self-selected their diet compared to what we had given them. >> Was timing of food intake impacted because when I think of what impacts what reduces slow wave deep sleep, it's eating too close to bedtime. >> Mhm. So, we did not take that into consideration in that study. We didn't We didn't look at that. We had their their food intake profile and didn't specifically look in that phase when when was their last eating period. But it could have been different
37:45 than in the controlled feeding condition because in the controlled feeding condition, they had set meals at specific times. But they all went to bed at 10:00 p.m. Then the other question was, "Okay, what was it that they ate that day that impacted how they slept that night?" And we found that higher intakes of fiber were associated with more deep sleep. Higher intakes of saturated fat, less deep sleep. And then more refined carbohydrates, simple sugars, more arousals. So, when we talk about arousals in the context of polysomnography, it doesn't necessarily mean full-on waking up or awakening. It really means going from a deeper to lighter stage of sleep, so you may still
38:30 be asleep throughout the night, but you're not getting deep slow-wave sleep, REM sleep as much as you would uh otherwise. >> Do you create a buffer between your last bite of food and the time you go to sleep, you personally? >> Me personally? Yes. >> Is it an hour, 2 hours, 3 hours? >> I personally like to eat my last meal at least 3 hours before going to bed. And I know there's variability there. Different people have different uh tolerance. You mentioned right before that uh you know, some people may be later chronotypes, but you what we know is that eating earlier is better overall. For cardiometabolic health, eating earlier is better. Me
39:17 personally, I feel I feel better by eating earlier. If I eat too close to bedtime I I get I get hot. >> Right. Yeah, it's [laughter] a it's a thermic effect of food. >> don't want to be cooling off when we go to sleep. >> Exactly. Exactly. >> I'd like to take a quick break and acknowledge our sponsor, AG1. AG1 is a vitamin, mineral, probiotic drink that also includes prebiotics and adaptogens. I discovered AG1 way back in 2012, long before I ever had a podcast, and I've been taking it every day since. The reason I started taking AG1 and the reason I still take it every day is because AG1 is to my knowledge the highest quality and most comprehensive of the foundational nutritional supplements on the market. AG1 is designed to support things like gut health, immune health, and overall
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40:51 subscription. There seems to be something asymmetric about sleep requirements in my experience, and I don't think I'm alone in this. Whereby if I go to bed at 10:00 p.m., I get into bed at 9:30, fall asleep at 10:00, I need about 6 and 1/2, maybe 7 hours to feel completely rested. That's how long I'll sleep, wake up without an alarm, feeling great. If I go to bed at midnight, I find I could sleep till 9:00 and still not feel completely rested. So, there's some weird sleep inertia stuff going on there, etc. The old adage is every hour before midnight is worth two after, but is there any real data to support that, or is this just all subjective and
41:36 conjecture? >> I'm not sure there's data to support that. I haven't seen anything. But, what I can say from what you're saying is that if you usually go to bed at 9:30, 10:00, and then all of a sudden you go to bed at midnight, now you're kind of out of line with your personal circadian system, right? And it's always harder to to get a good night's sleep if you're not going with your internal clock or your internal circadian preference. Um this is what happens with shift workers, right? For example, they they they're not sleeping at night, They're trying to sleep during the day. They're trying to sleep during the day where their melatonin is low or it should be when it's high. So, they're fighting
42:21 their circadian system. So, yes, they should they should be getting 7 hours, but they're not getting 7 hours because the body's not designed to be sleeping during the daytime hours. Plus, then you have you know, everything else, right? That >> Right. The light, the stress. >> noise, the kids, the whatever life that that happens during the daytime when everybody else is awake and you're trying to sleep. >> Yeah, the only thing I can think of that's an advantage to being nocturnal is the quiet. >> [laughter] >> I used to sometimes shift to a nocturnal schedule during holidays in graduate school when everyone go home because I lived my my parents lived relatively close to where I went to graduate school, so I could afford to just just go home for Christmas, right? Just that day or a couple of days and everyone else had to travel. So, I could invert
43:07 my schedule. It just kind of drifted that way. >> Yeah. >> I promise that's the only advantage of going to bed at 4:00 a.m. and sleeping until, you know, 3:00 p.m. at least for typical people. Your brain gets into a kind of weird space when you're inverted from the rest of the world. >> Well, the things you do when you're a grad student. I would be the opposite, right? I I'd wake up at 4:00 a.m. and then study because I felt like all of the hours of studying before the sun rose were like extras. >> Interesting. >> Extra time for me. >> extra. You felt like you were extra sharp at those hours? >> Extra sharp. I could study and then, you know, I got that time done and then, you know, breakfast, but then I crashed later in the afternoon. >> the problem. The 1:00 2:00 p.m. crash. Um, has your work explored napping at
43:54 all? I'm a believer in naps and non-sleep deep breaths, yoga nidra type things, meditation. Do naps factor into this diet, nutrition, hunger equation? >> So, we I done research on napping per se. For me, there a lot going on with napping. I don't think we have very good data to be able to say what's appropriate about napping. What we do know is that you don't want to nap too close to bedtime because you want to build sleep pressure throughout the day. And if you're dissipating the sleep pressure, the sleep need too close to bedtime, then you're not going to be able to fall asleep when time time comes to go to bed at your usual hour. And then, you know, you get into this vicious cycle, and it's it's not
44:40 helpful. But, you know, there are some studies that say, "Well, what should you do if you can't sleep enough at night and you're feeling tired?" You know, should you sleep? The recommendations are that you should make it a short nap, 30 minutes, no more than an hour, early enough in the day, if possible, so that you can have sufficient time to rebuild that sleep pressure to be able to fall back asleep well when time comes. But then there's also this this whole question about what's a nap for? Right? Like why are you sleepy? Of course, if you if you pulled an all-nighter, it's easy to to know. But if if you had sufficient sleep or sufficient opportunity for sleep at night and you're waking up and you're not feeling refreshed, and not feeling
45:26 like you had good quality sleep, and then you're not able to maintain alertness throughout the day, and you need a nap, I think you should you should check to see like what's going on at night. Like why are you not getting that good good enough sleep? >> I'm chuckling because my post-doc advisor sparked this huge debate. It was a big lab. And we had a couple of people in the lab who liked to nap at their desk. These were people that could just like put their head down and and nap at their desk in the afternoon. You'd walk in, they'd be napping, and then they'd wake up and keep working. Everyone was working very hard. And he had this theory uh that if you're napping, it's because you're sleep deprived. That like napping is unhealthy, you know. And it it sparked a big debate. And people because it were a bunch of nerds, people bring data in like, "No, you know, at the
46:13 sleep lab at Stanford says that naps can be healthy." And I think it you what you just described summarizes I think that the takeaway. I'm a believer in the short nap. But but I'm one of these people that can sleep anywhere, anytime, which may be reflective of sleep deprivation. >> Maybe, yeah. >> Do you find that like when you're going to design a study or when you're going to like really work, like this 4:00 a.m. time, that it's a time of calm or are you like a lazy Are you Do you feel like your mind is moving fast or you're kind of in this like flow zone or whatever you want to call it? >> I'm very focused. >> Mhm. >> Uh, very efficient. So, I try to be really attentive at my task. I try to take take breaks once in a while, but uh most of the time it's it's very
46:59 efficient. Get to the task and get it done. >> Earlier you were talking about biking in the work. You strike me as somebody who I always think of people who I'm always impressed by colleagues like this that their life is kind of like a step function. They wake up and it's like they're into the day and then it's down, right? Yeah. Interesting. I think some of us are more like this. >> But I think it's important to have a little bit of both though. I think it's important to have downtime, you know, speed time, to to not just be go go go go go. Like you were asking about my personal you know, actions. And at one point I was running a lot for exercise. And uh I felt like my whole life was just
47:46 running all the time. >> Your brain, too? >> Yeah, yeah. Run to get my kids to school, run to work, get work done, run to then run for fun. Run, run, run. And then I thought, "Okay, I got to need to >> [snorts] >> I think I need a breather. And so I started incorporating yoga into my uh my exercise routine. I think that's I think that's good. Actually, when I was a grad student, I thought yoga was stressful because I couldn't [laughter] stand in those poses. >> Exactly. >> Yeah. >> But I think yoga evolved. I think the yoga that I do now, it's not as static >> Mhm. >> as the yoga I was doing when I was a grad student. I think it evolved to be a little more active than uh than back then. I see the benefit to having, you know the
48:31 both types of uh exercise. >> Thanks for being willing to explore that. You know, the I'm not an Ayurvedic practitioner, but the Ayurvedic folks, they'll talk about people like more fire, more more earth, where, you know, and and I think it's just a different lens and nomenclature on there's a kind of array of phenotypes. But when we talk about this thing, sleep, it becomes very prescriptive, right? It's like we all need 6 to 8 hours. I mean, I actually, from what you're saying today, six sounds like insufficient is what I'm hearing. I'm probably a little sleep deprived is what kind of hearing. >> So, you know, a colleague of mine just published a paper in nature about biological clocks and aging in different organs. And the sweet spot really was 6 and 1/2 to about 7 and 1/2 8 hours for
49:18 optimal aging. Once you get to below that, it's basically U-shaped, right? So, too much of one thing is not good, too too little is is not good. You want to be in the sweet spot most most organs for uh optimal aging was in this 6 and 1/2 to 7.8. And it differed a little bit by men and women, depending on which organs he was looking at. Uh a little longer for women. Um some of the curves were different, where, you know, some are more pronounced U-shapes in in men than women in different organs. So, uh very interesting paper. >> Mhm. Came out last week or 2 weeks ago. >> I'll have to check it out. Um, what other uh sex differences uh are known to exist in sleep requirements, sleep dynamics that from your work or from other work? This is not something we've
50:04 really covered on the podcast. >> No. >> No, I mean, well, not in in any sufficient amount of detail. >> Yeah. >> So, women tend to sleep a little longer than men across lifespan. Although, you know, if you ask women about their sleep, they don't rate their sleep as very good. Um, more women than men report having difficulties with sleep, insomnia, for example, insomnia symptoms. More women than men say they have difficulty falling asleep, difficulty maintaining sleep uh across the adult lifespan. >> Why do you think that is? >> There could be some physiological effects, right? Some hormonal effects. Women uh don't sleep the same across the menstrual cycle. Uh there's discomfort at different times. Uh and then there's different responsibilities, different social roles that come into play uh that may
50:51 influence women differently than men. But, you know, we were working on a on a review paper actually about hypertension and and sleep and sex differences. And, you know, women are more sensitive to the impact of poor sleep on different metabolic outcomes than men. So, for blood pressure, at lower sleep apnea, for example, at lower thresholds of sleep apnea, their blood pressure would be higher uh than men. So, I think that there needs to be uh for sure a lot more research in this area to be able to uncover, you know, these these differences. And then, you know, knowing that there are these differences to start probing uh women about their sleep. Last year, we published um a scientific
51:37 statement for the American Heart Association about multidimensional sleep health. And we concluded by uh recommending clinicians that they actually ask their patients about sleep. And not ask a question a targeted question, just ask their patients, "How's your sleep?" Because if you start asking about, "Oh, how much sleep do you usually get at night?" Then you tell the person that the only thing that matters is how many hours of sleep you got at night. That's not all sleep is about, right? Sleep is not just about the number of hours that you got, but it's also about the regularity, the quality, your satisfaction with it. Uh you're There's nighttime experiences, there's daytime experiences from sleep. When you wake up from sleep, are you feeling refreshed?
52:24 Are you feeling like you had Are you satisfied with how much the sleep you got the night before? During the day, are you staying alert? Are you vigilant during the daytime hours uh from your past sleep experience. So, having this open-ended question, maybe maybe clinicians uh won't have time for for uh for the answer, but, you know, it allows the their patient to actually tell them what's bothering them about their sleep. >> Mhm. >> Then you can get to something like, you know, my my spouse keeps kicking me because I'm snoring too loud. Then, "Oh, well, maybe we should test you for sleep apnea." >> Does apnea always include snoring? Yes. So, are there some people who don't snore who have apnea? >> I don't think so. You stop breathing, and then there's this gasping
53:11 sound that people make when they uh they awaken from that. Or they get aroused from from this breathing interruption. >> I feel like so many people have apnea and don't realize it. Not because I'm sneaking into their rooms at night and listening to if they snore, but it is just remarkable how many people I speak to who say, "Yeah, I found out I had apnea because I saw that I was snoring because they started monitoring their sleep." And there's generally a snoring index on these. Or now there are free apps that can just record you while you sleep. So, I know a lot of people are I don't mouth tape uh when I sleep, but I I did I do uh sometimes use one of these nose strips that kind of pulls the nostrils out a bit. That certainly it's reduced the amount of snoring >> That will reduce the amount of snoring,
53:57 but the sleep apnea is from the throat, right? So, the closure in the throat that it uh that uh obstructs the trachea and that's what then prompts the awakening and breathing and then the sound that comes from there. Actually, weight loss is typically like the first line treatment if someone has excess weight to start losing weight, that might help with the uh with sleep apnea. And then there's CPAP which yes, people don't like, but if they are at a lower weight where the apnea is milder, the pressure may be not as uh not as high, so that might be helpful for comfort. I have a colleague of mine who does uh sleep apnea surgeries. So, implantables
54:43 are also >> Oh. >> If people think they might have apnea, is it just get a CPAP, pop that thing on? Is that the best line of of entry? >> I think they should uh they should get tested. >> So, how do we How does one do that? Cuz that's the problem. >> if you're suspecting that you may have sleep apnea because you've been told that you snore, because you wake up and you're not feeling refreshed, and you're feeling sleepy during the day, I think you should talk to your doctor about this and definitely, we have polysomnography is the first line you know, is what we use to detect um sleep apnea. But, there's in-home sleep testing that can be done, so you don't have to stay overnight in a lab for for uh to get tested for this, and uh and your doctor can prescribe that test very easily.
55:29 >> How come we can't just go buy a CPAP on Amazon? >> Because you need to have the the the pressure determined for you, right? So, you need to know what kind of pressure to apply and you know, how to set it up. Uh it's not as as simple as just you know >> Okay. All right, fair. >> You need it it needs to have the proper settings and someone needs to tell you which setting to use because then that's where you run to the trouble of having the wrong settings and and not being effective. >> Yeah, I just know from having done this podcast long a while that like if people think, "Okay, I got to go to my doctor. I got to find out or convince them that I have apnea. Then they have to like write me a script for a CPAP. Then I got to buy a CPAP which I'm guessing is not cheap." >> I'm not sure. >> I I don't think they're very inexpensive. They might The price might have come down. And I got to sleep with
56:15 this thing on my face like looking like Darth Vader so I don't sound like Darth Vader. I just think very few people are going to do it. So, somebody out there should like come up with an at-home solution to this. Something like apnea seems important enough to daytime wakefulness, cognitive function, longevity, metabolic like it works out to so many things that I feel like it >> If you use >> it deserves a like a public health messaging. >> Yeah, if you use it well and you feel better during the day, that's a that's reinforcing, right? To keep using it. And and get treated for it. >> Let's talk about food and nutrients. You've done a substantial amount of work here in this area and I have a bunch of questions. But first I want to talk about kefir. >> Yeah. >> I love Bulgarian full-fat plain yogurt, but it's right next to the kefir.
57:01 >> Uh-huh. >> And I'm always like, "Do I get the kefir?" Well, I don't know. I love the Bulgarian full-fat plain yogurt. So, I haven't tried the kefir yet. What's special about kefir and why are why did you study kefir? >> Kefir we we studied because it was a fermented dairy product, uh probiotics. We figured, you know, maybe it will improve uh cholesterol synthesis based on its impact on short-chain fatty acids. So, that was a the the subject of my uh master's thesis. Over that study, uh that was when I was at McGill. We were recruited men that had mildly elevated cholesterol levels. We gave them two cups per day versus just regular milk for a month. >> So, two cups like two mugs like this? >> Two cups like the measuring cup.
57:46 >> Okay. >> Yeah. >> Okay. >> Um like 500 ml. >> Okay. >> And uh and we measured their the amount of cholesterol they they produced at baseline and point in both phases and there was no effect. It was a null study. It was one of those. It was hard to get published. >> Mhm. >> Kept at it and and we got it published, but yeah. >> So, these fermented yogurts and things they don't do anything for for cholesterol levels. >> At least in our study, in this population, at this level, with this comparison >> Mhm. >> didn't have any effect. >> What's your general thought about uh low sugar fermented foods? I don't know if kefir uh qualifies as low sugar, but based on Justin Sonnenburg's work at Stanford and others I've been I've been
58:32 a really bullish on this idea of sauerkraut kimchi uh full-fat Bulgarian yogurt. Fermented foods are are interesting. >> Yeah. >> Are you a proponent in general? >> I'm a proponent. Yeah, absolutely. I think it's important to feed your gut. I think that uh the gut microbiome is uh getting a lot of attention for all sorts of, you know, uh health benefits. So, I think that that's something that's uh that's is important. So, also it's important to also consider that, you know, for that study, right? Our main outcome was cholesterol synthesis, but there's so many other things we could have looked at that we didn't look at, right? And maybe it didn't have any impact for cholesterol synthesis, but maybe
59:20 glycemic control might be better or for gut inflammation it would be better. But, you know, you you pick your outcomes, right? You study something and the >> This is the challenge of doing controlled science. >> Yeah, yeah, yeah. >> So, the opposite end of the like X, what used to be called Twitter, science, where like people just like report anecdotes, but actually anecdotes of that sort have become very powerful now in the public health space, for better or worse. Like people, you know, because I we can look at any study and say, "Well, that's a very artificial circumstance." You say, "Well, intentionally, because we're trying to isolate variables." >> Right, right, right, exactly. >> People get frustrated. "Oh, that's an observational study." Well, uh I'm going to continue to eat low-sugar fermented foods every day. I I I do think in a study like the one you
1:00:07 described, occasionally there's just there's Let me state this differently. Historically, in science, there's been a lot of interesting discoveries that have come from researchers designing a study to look at one thing and then kind of noticing, "Oh, like all the subjects feel better or sleep better or their skin they they're reporting things that then lead to an another another line line of inquiry, but you moved on from kefir. Tell me about this um this paper. I was intrigued by this when I looked over your CV. The uh a weight-loss diet that includes a coffee beverage enriched in, let me try this, mannan oligosaccharides. >> Yeah. >> Okay. All right, long word. Leads to a greater loss of adipose fat tissue than placebo beverage in overweight men. >> Yeah.
1:00:52 >> Tell me about this study and what these mannan oligosaccharides are and if somebody wants to lose weight, should they be including this in their coffee? >> So, this was industry-sponsored research that I did. Um they wanted to replicate a study that had been done in a different country >> [snorts] >> because they wanted to replicate the findings. So, we did this study. Uh it was basically a placebo-controlled study. We got we were provided um coffee mannan oligosaccharides. So, these are extracted from spent coffee grounds. So, it was basically sachets, right? So, a white packet. One had the coffee mannan oligosaccharides, the other one didn't. We gave it to our study participants. We measured their body composition. We found an effect on
1:01:38 body composition in men, not in women. >> Hm. >> And so, that was the end of that product. >> Really? They wouldn't market it just because [clears throat] it only had an effect in men? >> Yeah. Yeah, they were like >> I assure you there are many men who would love to drink a coffee drink and lose weight as a consequence. >> to be our market, you know. >> But, do we know what the ingredients were? >> It was mannan oligosaccharides. Just the extracted Yeah, so it was just basically a product that was tasted like coffee, strong coffee. But, it didn't have the caffeine or anything like that. It just had this this mannan oligosaccharide that was extracted from coffee. >> So, this substance comes from coffee ordinarily, but coffee is very low low calorie. >> Right. But, it's from the spent grounds. So, you No one really consumes this really because you know,
1:02:25 when you brew your coffee, you're you're not getting it to know. >> Can you buy it? Can people get it? >> I don't think so. I'm not sure. >> So, what What do you First of all, how much weight did they lose relative to the >> It was statistically significant. Yeah. >> Hm. Okay. I was intrigued by it cuz I thought there's there's something that I mean, you studied It's interesting you say kefir mannan oligosaccharides from coffee. >> Yeah. >> Now, I'm going to ask you about ginger. >> Well, when I was in a graduate student, I was interested in functional foods. >> Mhm. >> And I was interested in those foods that provide health benefits beyond their nutritional value. >> Mhm. >> Right. So, kefir is a fermented dairy product. It would We were studying it for its a functional benefit on cholesterol synthesis.
1:03:12 That's not a uh that's not a function of dairy, right? Dairy is you consume it for bone health, right? So, it's the basically when we talk about different claims that foods have, you know, there is those structure function claims, like consuming dairy contains calcium that's good for your bones, and then there is um functional claims. Those functional claims are health claims, we call them, that say, "Okay, well, health claim there's a health claim for oats, for example, right? So, consuming fiber from oats uh reduces cholesterol levels." >> That's been demonstrated. >> Yes. So, that's that's a health claim. That's an approved health claim. That's why you see the hearts on some boxes of cereal, but that's different than
1:03:57 fiber is good for maintaining regularity, right? So, anyways, I was interested in in functional foods for health benefits beyond their their nutritional content. And so, uh we we study kefir for I study kefir for my master's degree, and then for my PhD, studied uh medium-chain triglycerides, um and then um
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