Andrew Huberman interviews nutritional medicine professor Dr Marie Pierre St Onge on the bidirectional relationship between sleep and diet
Andrew Huberman speaks with Dr Marie Pierre St Onge, professor of nutritional medicine at the Institute of Human Nutrition at Columbia University School of Medicine.
Summary
Andrew Huberman interviews Dr Marie Pierre St Onge, whose laboratory is one of the few in the world studying the bidirectional relationship between sleep and food. Dr. St-Onge presents findings from controlled inpatient studies showing that even modest sleep restriction — as little as an hour and a half less per night — increases caloric intake by 250–400 calories per day, with sex-specific hormonal mechanisms: sleep-deprived men show elevated ghrelin, while sleep-deprived women show reduced GLP-1. She also presents the reverse direction: that higher fiber intake is associated with more deep slow-wave sleep, while saturated fat reduces it and refined carbohydrates cause more nighttime arousals. The conversation extends into meal timing, medium-chain triglycerides, functional foods including ginger and kefir, the portfolio diet for cholesterol reduction, and the challenges of publishing null results in nutrition science.
Key Takeaways
FULL TRANSCRIPT
Introduction and the bidirectional sleep-diet relationship
Andrew Huberman: 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 they're just in control in a different way. Maybe you could share for us what's really going on beneath that experience, and when subtle or not-so-subtle chronic sleep loss — not an all-nighter necessarily, but 45 minutes less here, 90 minutes less there — how that plays out in terms of our nutrition. And then we'll go from the nutrition side to sleep.
Dr Marie Pierre St Onge: Sure. There are a couple of questions in there about the extent of sleep loss and how that influences food intake — what we see in the general population versus what we do in a lab to address causality. Let me start with the population-based studies. When I started being interested in sleep, it was coming from an obesity angle. My PhD is in nutrition. I trained as a postdoc in body composition and 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 an adequate amount of sleep. Then it became clear there is a higher prevalence of people with obesity in the short-sleep group. Then studies evaluating changes over time showed that people who don't sleep enough tend to gain more weight. There was a famous nurses' health study that I really like to cite when I give talks, published in 2006, where they tracked nurses over 14 years. Those nurses who reported sleeping five or six hours had a much higher rate of weight gain over that 14–15 year period than the nurses who reported sleeping seven or eight hours per night.
Those are observations from large-scale population studies and cohorts, but what those studies tell us is that things are happening at a point in time, or may influence something happening over time, but not necessarily that one causes the other. So I started my work in this field trying to uncover whether sleeping too little actually causes weight gain. Because I was coming from a lab where I trained in the measurement of energy balance — how much energy you eat versus how much energy you burn — I thought, well, if sleep leads to obesity and weight gain, it has to impact this energy balance regulation. It's either that we eat more than we should, or that we exercise less and burn less, or maybe it's a combination of the two. Let's try this out and see.
My first study, my first NIH grant — the big R01s — was to look at exactly this. We had people who had adequate sleep, and we brought them into the lab and asked them, in a crossover design, to either sleep adequately — a 9-hour time-in-bed opportunity — or to sleep too little, with a 4-hour time-in-bed opportunity. Very short, but we did this for five nights. Then we took all sorts of measurements in a controlled feeding condition. For the first three days, we had participants eat the exact same thing regardless of how much time in bed they got at night. We measured appetite-regulating hormones. We did neuroimaging to isolate the impact of sleep duration on appetite-regulating hormones and neuronal responses to foods. And then on the last day we let them self-select their food intake and measured that in the lab.
From that study, we showed that in men specifically, we saw an increase in ghrelin in response to short sleep — this hormone that triggers food intake. In women, we saw a reduction in GLP-1, interestingly enough — glucagon-like peptide-1, the satiety hormone — as a result of short sleep. And when we measured their food intake in the lab, they ate 300 calories more in the short-sleep condition than when they got their regular adequate sleep of at least 7.5 hours per night.
We also looked at neuronal responses to food stimuli. We found upregulation in reward centers of the brain in the context of sleep restriction compared to adequate sleep. So altogether, we were 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. And that could also be impacted by pleasurable centers that are activated to a greater extent as a result of insufficient sleep.
Andrew Huberman: Amazing. This sex-specific split in the data — if I have it correctly — is that when men are sleep-deprived, getting four hours per night, the signals that drive appetitive desire to eat are higher. In women, it's more that the brake on eating, on satiety, is reduced.
Dr. St-Onge: Exactly.
Andrew Huberman: As far as I know, the GLP pathways are not divergent by sex, but of course I'm not deeply versed in that literature. Is there any evidence that GLPs are functioning differently in men and women — circadian-wise or anything like that — or was this just an incidental outcome?
Dr. St-Onge: This was an incidental outcome. We really didn't know what to expect. We didn't know at all that we'd see sex differences.
Andrew Huberman: Because there had been prior studies, and those had shown that ghrelin was increased as a result of sleep restriction. They also showed that leptin was reduced. And when you got your data, if you analyzed it with all participants together —
Dr. St-Onge: There was no effect.
Andrew Huberman: And that was surprising.
Dr. St-Onge: And people would say, "Don't you know sleep restriction increases ghrelin?" Like, well, I guess I don't know, because in our study it doesn't. But then we saw these sex-specific differences, and then it made sense — 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.
Sleep deprivation, cortisol, and metabolic effects
Andrew Huberman: Whenever I'm sleep-deprived — four or five hours, which I consider sleep-deprived — I feel like my whole body is in a low level of pain. It's like a kind of central ache. And I wonder to what extent people eat to overcome, to quell, the pain of sleep deprivation. Maybe people react differently to sleep deprivation. What do you think is happening in that relatively short amount of missing sleep? What is getting reset? Is it neural? Is it endocrine?
Dr. St-Onge: In our study, it was actually a 50% reduction in sleep. When they had the 9-hour sleep opportunity, they slept around 7.5 hours. We had screened all participants to sleep at least seven hours, measured by actigraphy, and on average they got 7.5. In the sleep-restricted condition, they got on average about 3 hours and 50 minutes.
Andrew Huberman: So it's like staying up late working on a deadline and then trying to catch an early flight.
Dr. St-Onge: It's pretty brutal. And that was maintained for five nights.
Andrew Huberman: Were they coming unglued mentally too? I think I would feel terrible after that kind of stretch.
Dr. St-Onge: By the end, they were done. There was no way anyone would want to keep coming back for that. But they were in the lab under supervision the whole time. We didn't let them go out on their own. No naps either. What happens is I think there's some subconscious need to eat more when you're sleep-deprived. There's also a thermic effect of food — it gives you a jolt of energy to eat something. People know that eating wakes you up in a way. There's neuronal signaling that enhances pleasurable and reward centers of the brain. And when fatigue sets in, do you really want to have this conversation with yourself about what to choose at the buffet table?
Others have also shown that sleepiness tends to correlate with all of this — that there are these triggers for more pleasurable food consumption with sleep restriction, and it's been reproduced. There's been so many studies, and they all agree on the extent of overeating. 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 — roughly 3,500 excess calories for a pound of body weight — and 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 in final exams, it's a real thing.
Neymar Coven in 2022 published a paper where they had sleep restriction of about five hours per night versus 7.5 hours per night for two weeks, and participants gained half a kilo in a two-week period. You do nothing, you just sleep less, and you gain almost a pound in two weeks.
Andrew Huberman: It strikes me that for a long time in stress research, the idea was that when people are stressed, they reach for comfort foods — carbohydrate, typically starch-fat or sugar combinations. The just-so story was always that cortisol's main role is to deploy glucose, and so people are doing this as a way to bring in excess energy. What is the relationship between the forms of sleep deprivation you work on and stress? Is what you're studying essentially stress?
Dr. St-Onge: So if you're thinking about physiological stress measured by cortisol levels, in that study cortisol wasn't changed in the short sleep condition.
Andrew Huberman: For five days of sleep restriction at basically four hours a night?
Dr. St-Onge: Cortisol was still peaking in the morning, still dropping in the evening.
Andrew Huberman: Wow. That's very surprising to me.
Dr. St-Onge: I don't know. I don't know if it's the context of being in a lab where everything is safe and taken care of. There's nothing outside to aggravate. So maybe when you're in the context of sleep restriction but also dealing with your daily life — needing to take care of your kids, needing to get to work, needing to do all the activities of daily living — maybe then that becomes the added stressor.
Andrew Huberman: So the message is: if you suffer less than adequate sleep, get someone to take care of everything else. You'd better be in a spa.
Dr. St-Onge: Exactly. And in that study also, we didn't see any effect on glucose or insulin. Nothing. The curves were superimposable — while they were eating the exact same food at the exact same time, in the exact same quantity. The only thing we changed was the amount of sleep opportunity they got at night. To me, this means it's a combination of different things that causes the metabolic abnormalities 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 — a poor diet that then triggers a worsening, compounded by the lack of sleep.
That's why we did a follow-up study to this severe sleep restriction study. Because we did not find any adverse impact on glucose, insulin, or lipid profile, we asked: 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? Because we had seen that food choices were different — that they ate a diet higher in calories, higher in fat and saturated fat — we thought maybe if you're in a free-living situation, that's when you start to see those cardiometabolic outcomes, compounded by more sedentary behavior and alterations in food choices.
So the follow-up study recruited good sleepers — people who sleep at least seven hours per night, verified by actigraphy, who reported good sleep quality on questionnaires. We then said: you're either going to continue your excellent sleep, or you're going to go to bed an hour and a half later, so that you get an hour and a half reduction in sleep. Because when we screened people sleeping at least seven hours, they slept about 7.5. Reducing by an hour and a half gets to six hours, which is what people who don't get enough sleep typically report. And now when we did that, we saw that insulin resistance was increased after six weeks of sleep restriction compared to adequate sleep. Insulin sensitivity was reduced — worse actually in post-menopausal women compared to pre-menopausal women. Blood pressure was increased. Those cardiometabolic outcomes were adversely impacted by free-living mild sustained sleep restriction for six weeks.
Energy expenditure and spontaneous movement
Andrew Huberman: What's kind of the action end of things that causes them to gain weight if they're basically on an isocaloric diet? I have an idea what it might be, but I'm curious what the answer is.
Dr. St-Onge: I think they're more sedentary during the day. Less spontaneous activity. We also did a study to look at energy expenditure — which is actually really difficult to measure. We enrolled only women for that and used a metabolic chamber at Columbia. It's a small room in which we keep people and measure minute-by-minute oxygen consumption and carbon dioxide production. We were able to show that energy expenditure is actually increased in the context of sleep restriction in the metabolic chamber, because it's more costly energetically to remain awake than to fall asleep. So energy expenditure when participants were awake was identical in both conditions regardless of how much sleep they got the night before.
Andrew Huberman: So it's fidgeting, movement — the non-exercise-induced thermogenesis. It's a big number. People who fidget a lot, bounce their knee a lot — sometimes these people are burning 1,500 calories more per day. It is interesting to observe people out in the world. You sometimes see that people who are very lean tend to have a lot of spontaneous movement. They tend to stand up quickly, walk quickly. These things add up over time in ways that most people underestimate.
Dr. St-Onge: For us it was about a 5% increase in energy expenditure, ending up being about 90 calories — nowhere close to the 300 calories more of intake they got 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 energy expenditure — again, in the confines of a metabolic chamber, which for most people is equivalent to the size of their bathroom. You have a bed, a table, a sink, a toilet. That's it.
Sleep deprivation, inflammation, and behavioral awareness
Andrew Huberman: A little while ago I saw a study that said if you are one night sleep-deprived — getting one or two hours less sleep than you normally need to feel rested — it's actually advantageous to exercise because it offsets some of the increase in inflammation. But if you're going multiple nights that way and exercising regularly while sleep-deprived, it sets up a susceptibility to illness and injury. How much of what you observe under conditions of sleep deprivation do you think is downstream or upstream of inflammation? Or can we pinpoint specifically what's happening?
I think about this sometimes when I'm thinking about my diet. I'm like, do I really want to eat this, or is it because I really didn't sleep last night? You can ask yourself these questions, take a pause, and say: do I really want dessert, or is it just that I'm tired?
Dr. St-Onge: 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 appropriate choices. Say, "Okay, I probably don't need the extra calories right now." Or maybe you say, "I had a really bad night last night and those extra calories, I don't really care — they're going to make me feel good and I need a pick-me-up." But those are all choices to make, because mood comes into play as well.
How diet affects sleep quality
Andrew Huberman: That brings us to the other direction of the equation — how what we eat impacts our sleep. This is something most people have heard about in the context of not eating too close to bedtime. This is an active debate in many households. Some people seem to be fine eating close to bedtime. Other people find it really disrupts their sleep. I'm interested in both the timing of food intake relative to sleep and the content of the food and how it impacts sleep.
Dr. St-Onge: When we started this conversation, I was telling you about population-based studies — cross-sectional data where two things happen at the same time and you don't really know causality. Early on in this field, we started thinking about sleep as the promoter of food intake, but didn't really think that maybe it's the other way around, or that the other way around is just as plausible. So I started thinking about that and said, what if we took the other approach? What if we looked at diet and examined how diet influenced future sleep?
My first paper in this field used data from the Multi-Ethnic Study of Atherosclerosis — MESA. It's actually kind of hard to find good cohorts that have good nutrition data, good sleep data, and data over years. MESA is one of those great cohorts in the US that has all of the above. I paired up with a colleague of mine, Susan Redline in Boston — she's a principal investigator on their sleep ancillary study — and we asked the question of diet quality and its impact on sleep duration and insomnia symptoms. 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.
That launched a whole field of study. We've looked at this in different studies and different cohorts. Earlier this year we published data from the Women's Health Initiative — another large cohort with good diet data and sleep information. We took a really nice approach in this longitudinal analysis. Usually when we do longitudinal studies, we exclude people who have the condition at baseline. But insomnia is one of those conditions that's not necessarily static — it resolves. You can have insomnia and then a few years later not have it, or you can not have it now and develop it. So what we did was break our participants into two groups: people who had no insomnia at baseline and at three-year follow-up, and participants who had insomnia at baseline but not at three years — so they were in the healthful, improving-sleep group. The other group was all those women who had insomnia at baseline and at three years, and those with no insomnia at baseline but insomnia at three years — the persistent or progressing-toward-poor-sleep group.
We found that women who had a diet more closely aligned to the Mediterranean diet — and we also looked at the DASH diet, the Dietary Approaches to Stop Hypertension — were less likely to have insomnia at three years.
Andrew Huberman: What is the DASH diet?
Dr. St-Onge: The Dietary Approaches to Stop Hypertension was developed to reduce and prevent hypertension by increasing intakes of fruits and vegetables, nuts and seeds, consuming low-fat dairy, and more plant-based types of diet. It has been tested in both a low-salt and regular-salt profile.
Andrew Huberman: How did those work out? Do you recall if the low-salt versus high-salt condition made a difference?
Dr. St-Onge: There is salt sensitivity, so there are some people who are very sensitive to salt and having a reduced-salt diet will really improve their blood pressure. Others, not so much. But the DASH diet regardless of its salt content did better than the equivalent non-DASH diet — your average American diet, higher in saturated fat and sugars.
Andrew Huberman: Which seems to be changing now because of the GLPs. I feel like the typical American diet 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.
Dr. St-Onge: GLP-1s will do that.
Andrew Huberman: How many Americans have tried a GLP? The estimates are anywhere from one in seven — some people say it's more.
Dr. St-Onge: Which is pretty incredible. Yeah, it's pretty high.
Andrew Huberman: But this is interesting. How do you separate out the variables in a study like that? People who are eating a Mediterranean diet are probably also more apt to walk more, exercise more, socialize more.
Dr. St-Onge: In population-based studies, we adjust for a bunch of covariants. We have questionnaires asking about race, occupation, socioeconomic status, different illnesses they may have, depression, physical activity level. We try to take all of this into consideration. Obviously there are always unmeasured factors — social interactions, for example, are usually not captured very well. But one thing we did in my lab — going back to that original study — was to look at how diet influenced sleep at night in the participants in our inpatient study. We took the 9-hour time-in-bed opportunity phase only. In the 4-hour phase, participants were very efficient — there wasn't much variability in sleep duration. But in the 9-hour phase, there was variability. Some people got more or less. So we wanted to see if food intake was related to their sleep at night.
That study had polysomnography assessments of sleep every single night. We had a controlled diet initially and then let them self-select their food intakes. We asked: first, was the diet they chose different from the diet we gave them? It was. They ate almost 450 calories more. They ate 33% more saturated fat, a little less protein, a little more carbohydrates.
Then: was their sleep at night different when eating the diet we fed them compared to what they self-selected? It was different — not in terms of duration, but in time to fall asleep, which was over 70% longer when they self-selected their diet. And their slow-wave sleep — deep sleep — was about 20–23% shorter when they self-selected their diet compared to what we had given them.
Andrew Huberman: Was timing of food intake a factor? Because when I think about what reduces slow-wave deep sleep, it's eating too close to bedtime.
Dr. St-Onge: We did not take that into consideration in that study. We didn't specifically look at when their last eating period was. It could have been different 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 p.m.
Then the other question was: 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 with less deep sleep, and more refined carbohydrates and simple sugars with more arousals. When we talk about arousals in the context of polysomnography, it doesn't necessarily mean full-on waking up — it really means going from a deeper to a lighter stage of sleep. You may still be asleep throughout the night, but you're not getting deep slow-wave sleep or REM sleep as much as you would otherwise.
Andrew Huberman: Do you create a buffer between your last bite of food and the time you go to sleep? You personally?
Dr. St-Onge: Me personally, yes.
Andrew Huberman: Is it an hour, two hours, three hours?
Dr. St-Onge: I personally like to eat my last meal at least three hours before going to bed. And I know there's variability — different people have different tolerance. What we know is that eating earlier is better overall for cardiometabolic health. Me personally, I feel better by eating earlier. If I eat too close to bedtime, I get hot.
Andrew Huberman: Right. It's the thermic effect of food. We want to be cooling off when we go to sleep.
Dr. St-Onge: Exactly.
Sleep timing, circadian rhythms, and napping
Andrew Huberman: There seems to be something asymmetric about sleep requirements in my experience. If I go to bed at 10 p.m., I need about 6.5 to 7 hours to feel completely rested. If I go to bed at midnight, I could sleep till 9 and still not feel completely rested. The old adage is every hour before midnight is worth two after. Is there any real data to support that?
Dr. St-Onge: 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 or 10:00, and then all of a sudden you go to bed at midnight, you're kind of out of line with your personal circadian system. It's always harder to get a good night's sleep if you're not going with your internal clock or your internal circadian preference. This is what happens with shift workers — they're not sleeping at night, they're trying to sleep during the day when their melatonin is low. They're fighting their circadian system. Plus, you have everything else: the light, the noise, the kids, whatever life happens during the daytime when everybody else is awake and you're trying to sleep.
Andrew Huberman: The only thing I can think of that's an advantage to being nocturnal is the quiet. I used to sometimes shift to a nocturnal schedule during holidays in graduate school when everyone would go home. I promise that's the only advantage of going to bed at 4 a.m. and sleeping until 3 p.m. Your brain gets into a kind of weird space when you're inverted from the rest of the world.
Dr. St-Onge: I would be the opposite — I'd wake up at 4 a.m. and study, because I felt like all of the hours of studying before the sun rose were like extras. Extra time for me.
Andrew Huberman: You felt extra sharp at those hours?
Dr. St-Onge: Extra sharp. I could study, and then I got that time done, and then breakfast — but then I'd crash later in the afternoon.
Andrew Huberman: Yeah, that's the problem. The 1–2 p.m. crash. Has your work explored napping at all?
Dr. St-Onge: We haven't done research on napping per se. For me, there's a lot going on with napping. I don't think we have very good data 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. If you're dissipating the sleep need too close to bedtime, you're not going to be able to fall asleep when time comes at your usual hour, and then you get into a vicious cycle.
But there are some studies that say, if you can't sleep enough at night and you're feeling tired, 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 rebuild that sleep pressure to fall back asleep well when time comes.
Then there's also this question about what a nap is for. If you had sufficient sleep opportunity at night and you're waking up not feeling refreshed, not able to maintain alertness throughout the day, and you need a nap — I think you should check to see what's going on at night. Why are you not getting good enough sleep?
Andrew Huberman: I'm chuckling because my postdoc advisor sparked this huge debate. It was a big lab, and we had a couple of people who liked to nap at their desk in the afternoon. He'd walk in, they'd be napping, then they'd wake up and keep working. He had this theory that if you're napping, it's because you're sleep-deprived — that napping is unhealthy. It sparked a big debate, and people brought data in. I think what you just described summarizes the takeaway. I'm a believer in the short nap, but I'm one of these people who can sleep anywhere, anytime, which may be reflective of sleep deprivation.
Dr. St-Onge: Maybe.
Andrew Huberman: Do you find that when you're going to design a study or really work at that 4 a.m. time, is it a time of calm, or does your mind move fast?
Dr. St-Onge: I'm very focused. Very efficient. I try to be really attentive to my task, take breaks once in a while, but most of the time it's very efficient. Get to the task and get it done.
Andrew Huberman: You strike me as somebody whose life is kind of like a step function — they wake up and they're into the day, and then it's down.
Dr. St-Onge: I think it's important to have a little bit of both, though. I think it's important to have downtime. At one point I was running a lot for exercise and I felt like my whole life was just running all the time. Run to get my kids to school, run to work, get work done, run for fun. Run, run, run. And then I thought, I kind of need a breather. So I started incorporating yoga into my exercise routine. When I was a grad student, I thought yoga was stressful because I couldn't stand in those poses. But I think yoga evolved — the yoga I do now is not as static as the yoga I was doing when I was a grad student. I see the benefit to having both types of exercise.
Sex differences in sleep and metabolic health
Andrew Huberman: When we talk about sleep, it becomes very prescriptive — we all need 6 to 8 hours. But from what you're saying today, six sounds like insufficient. A colleague of mine just published a paper in Nature about biological clocks and aging in different organs, and the sweet spot really was 6.5 to about 7.5 to 8 hours for optimal aging. Once you get below that, it's basically a U-shape — too much of one thing is not good, too little is not good. Most organs showed optimal aging in the 6.5 to 7.8 range, and it differed a little by men and women depending on which organs were being looked at — a little longer for women, with some curves more pronounced in men than women.
What other sex differences are known to exist in sleep requirements and sleep dynamics?
Dr. St-Onge: Women tend to sleep a little longer than men across the lifespan. Although if you ask women about their sleep, they don't rate it as very good. More women than men report having difficulties with sleep — insomnia symptoms, difficulty falling asleep, difficulty maintaining sleep across the adult lifespan.
Andrew Huberman: Why do you think that is?
Dr. St-Onge: There could be some physiological effects, some hormonal effects. Women don't sleep the same across a menstrual cycle. There's discomfort at different times. And then there are different responsibilities, different social roles that come into play that may influence women differently than men.
We were working on a review paper about hypertension and sleep and sex differences. Women are more sensitive to the impact of poor sleep on different metabolic outcomes than men. For blood pressure, for example, at lower thresholds of sleep apnea, their blood pressure would be higher than men's. There needs to be a lot more research in this area.
Last year we published a scientific statement for the American Heart Association about multi-dimensional sleep health, and we concluded by recommending that clinicians actually ask their patients about sleep — not a targeted question, but an open-ended one: how's your sleep? Because if you only ask how many hours of sleep you usually get at night, you're telling the person that the only thing that matters is the number of hours. That's not all sleep is about. Sleep is not just about the number of hours, but also about the regularity, the quality, your satisfaction with it, your nighttime experiences, your daytime experiences. When you wake up from sleep, are you feeling refreshed? During the day, are you staying alert and vigilant? Having this open-ended question allows the patient to actually tell you what's bothering them about their sleep.
Andrew Huberman: Then you can get something like, "My spouse keeps kicking me because I'm snoring too loud." And then: maybe we should test you for sleep apnea. Does apnea always include snoring?
Dr. St-Onge: Yes. You stop breathing and then there's this gasping sound that people make when they awaken from that breathing interruption.
Andrew Huberman: I feel like so many people have apnea and don't realize it. It is remarkable how many people I speak to who say they found out they had apnea because they started monitoring their sleep and there's generally a snoring index on these devices. Or now there are free apps that can just record you while you sleep.
Dr. St-Onge: Weight loss is typically the first-line treatment if someone has excess weight — start losing weight, and that might help with sleep apnea. Then there's CPAP, which people don't like, but if they're at a lower weight where the apnea is milder, the pressure may not be as high, so that might be more comfortable.
Andrew Huberman: If people think they might have apnea, is it just get a CPAP — pop that thing on? Is that the best line of entry?
Dr. St-Onge: I think they should get tested. If you're suspecting you may have sleep apnea — because you've been told you snore, because you wake up not feeling refreshed, and you're feeling sleepy during the day — I think you should talk to your doctor. Polysomnography is the first line to detect sleep apnea, but there's in-home sleep testing that can be done. You don't have to stay overnight in a lab, and your doctor can prescribe that test very easily.
Andrew Huberman: How come we can't just go buy a CPAP on Amazon?
Dr. St-Onge: Because you need to have the pressure determined for you. You need to know what kind of pressure to apply and how to set it up. It needs to have the proper settings, and someone needs to tell you which setting to use, because otherwise you run into the trouble of having the wrong settings and it not being effective.
Andrew Huberman: I just know from having done this podcast a while that if people think, okay, I've got to go to my doctor, convince them I have apnea, get a script for a CPAP, buy a CPAP — which I'm guessing is not cheap — and sleep with this thing on my face looking like Darth Vader so I don't sound like Darth Vader. I just think very few people are going to do it. Somebody out there should come up with an at-home solution to this. Sleep apnea seems important enough — daytime wakefulness, cognitive function, longevity, metabolic health — it wicks out to so many things that it deserves a public health messaging campaign.
Dr. St-Onge: If you use it well and you feel better during the day, that's reinforcing — to keep using it and get treated for it.
Diet quality, the Mediterranean diet, and functional foods
Andrew Huberman: Let's talk about food and nutrients. You've done a substantial amount of work here, and I have a bunch of questions. But first I want to talk about kefir. I love Bulgarian full-fat plain yogurt, but it's right next to the kefir. What's special about kefir, and why did you study it?
Dr. St-Onge: We studied kefir because it was a fermented dairy product. We figured, with the probiotics, maybe it would improve cholesterol synthesis based on its impact on short-chain fatty acids. That was the subject of my master's thesis. We were at McGill. We recruited men who had mildly elevated cholesterol levels. We gave them two cups per day versus just regular milk for a month — two cups like the measuring cup, about 500 mls. We measured the amount of cholesterol they produced at baseline and endpoint in both phases, and there was no effect. It was a null study. It was hard to get published, but we kept at it and got it published.
Andrew Huberman: So these fermented yogurts and things don't do anything for cholesterol levels?
Dr. St-Onge: At least in our study, in this population, at this level, with this comparison — no effect. But our main outcome was cholesterol synthesis. There are so many other things we could have looked at that we didn't. Maybe it didn't have any impact on cholesterol synthesis, but maybe glycemic control might be better, or gut inflammation. You pick your outcomes.
Andrew Huberman: Are you a proponent of low-sugar fermented foods in general?
Dr. St-Onge: I'm a proponent. Absolutely. I think it's important to feed your gut. The gut microbiome is getting a lot of attention for all sorts of health benefits, and I think that's important.
Andrew Huberman: The Sonnenberg and colleagues work on low-sugar fermented foods has been very informative for lowering the inflammatome — even more than fiber. In that study, within the fiber group, there was a fair number of people whose inflammation went way up when they consumed more fiber. But in the low-sugar fermented food group, it was always on average reduced.
Dr. St-Onge: Some people who increase their fiber intake, their inflammation decreases. For a lot of people, it increases — which is not to say that fiber is bad, but now we're starting to think about different types of fibers.
Andrew Huberman: They didn't control for that in that study. They just said increase the number of servings each day. And I know a lot of people don't like to eat fibrous foods because they don't feel good after eating them. I think there's a whole histamine story that needs exploration. Healthy foods need better parsing.
Dr. St-Onge: There was also habituation. You don't go from consuming six grams of fiber per day to 25.
Andrew Huberman: They ramped them up, but pretty high. Even the low-sugar fermented foods — I think they got them up to like four servings per day. It's a lot of kimchi. It can be a little hard on the gut.
I actually take an enzyme — I think it's called DAO — for digesting histamines. I noticed after I had whey protein or broccoli, I would get kind of sleepy. A colleague at Stanford, Sean Mackey, who heads our pain center, figured out by elimination and trial and error that it was onions and other histamine-containing foods causing him gut pain. Foods have real effects.
Now, you moved on from kefir. Tell me about this paper on a weight-loss diet that includes a coffee beverage enriched in manno-oligosaccharides, which leads to a greater loss of adipose fat tissue than a placebo beverage in overweight men.
Dr. St-Onge: This was industry-sponsored research. They wanted to replicate a study that had been done in a different country. It was a placebo-controlled study. We were provided coffee manno-oligosaccharides — extracted from spent coffee grounds — basically in sachets. A white packet: one had the coffee manno-oligosaccharides, the other didn't. We gave it to our study participants, measured their body composition, and found an effect on body composition in men, not in women.
Andrew Huberman: And so that was the end of that product?
Dr. St-Onge: They wouldn't market it because it only had an effect in men.
Andrew Huberman: I assure you there are many men who would love to drink a coffee drink and lose more weight as a consequence. Can people buy this substance?
Dr. St-Onge: I don't think so. It comes from the spent grounds — no one really consumes this because when you brew your coffee, you're not getting it.
Andrew Huberman: Now I'm going to ask you about ginger.
Dr. St-Onge: When I was a graduate student, I was interested in functional foods — foods that provide health benefits beyond their nutritional value. Kefir is a fermented dairy product we were studying for a functional benefit on cholesterol synthesis. That's not a function of dairy. Dairy you consume for bone health. So when we talk about different claims that foods have, there are structure-function claims — consuming dairy contains calcium that's good for your bones — and then there are health claims. There's an approved health claim for oats, for example: consuming fiber from oats reduces cholesterol levels. That's been demonstrated. That's why you see the hearts on some boxes of cereal.
Anyway, I was interested in functional foods for health benefits beyond their nutritional content. I studied kefir for my master's degree, medium-chain triglycerides for my PhD, and then ginger was something I offered to a grad student at Columbia. The McCormick company had an advertisement in one of the nutrition journals — they were going to donate spices for research. I had a grad student and I said, "Take a look at this list, come back to me if there's something we should test in the lab based on the things I do." He did some research and came back and said, "I think we should study ginger." I said, "Okay, to do what?" He said he thought we should look at energy expenditure — the thermic effect of food. So we did this study.
Andrew Huberman: What did the study look like?
Dr. St-Onge: We dissolved ginger powder in warm water — that was one beverage — and then in the crossover design, the next time they came in, it was just hot water. This was a one-time consumption period. We looked at the thermic effect of food over a 6-hour period. Participants were under a metabolic hood — a little bubble — and we measured their oxygen consumption and carbon dioxide production for four or five hours.
Andrew Huberman: And it was significantly elevated with ginger?
Dr. St-Onge: With ginger. Yes. We think through the capsaicin receptor there's an increase in the thermic effect of food. I was interested to see if there are little things we could do, little changes we can make to our diet to boost energy expenditure relative to intake — just to tip the scale. Because many adults over the course of their lifetime gain weight, and it's not a big imbalance in calories on a daily basis that leads to 10 pounds of weight gain over 10 or 15 years.
Meal timing and fat oxidation
Andrew Huberman: Someone had a really great question for me at the Obesity Society meeting a couple of years ago. You were showing data that if you eat foods later in the day, your fat oxidation is reduced. Tell me about that study.
Dr. St-Onge: We had participants on a controlled diet. They started eating one hour after waking up and had a 10-hour eating window, or they started eating five hours after waking up — a four-hour delay relative to the other condition. Same thing: a 10-hour window. We gave our participants the exact same foods, same quantity, same timing between meals. This was done in a metabolic chamber. The meals later in the day — consumed late relative to the earlier version of those meals — led to less fat oxidation.
Someone in the audience stood up and said, "So would you then recommend that people eat medium-chain triglycerides in their evening meal as opposed to a different type of fat?" And my eyes just went wide, because my time studying medium-chain triglycerides was 15 to 20 years ago. I thought that was fascinating — timing of intake of different foods and how it influences metabolism is something that's very interesting to me.
Andrew Huberman: I'm a first-bite-of-food-around-11-a.m. person. I'm trying to eat breakfast these days and shift things earlier. All it's really done is added a meal because I take my last bite of food usually around 8 p.m. I can't seem to get much earlier. But I and many other people have wondered whether it's best to eat more towards early day or whether it's just overall caloric load. You're saying it does indeed make a difference.
Dr. St-Onge: It makes a difference. You want to shift most of your caloric intake to the first two-thirds of your waking day. In that study, one hour after waking up — so basically 8 a.m. to 6 p.m. — is the eating window. It's a 10-hour eating window. It could be 8 a.m. to 7 p.m. Versus noon to 10 p.m.
Andrew Huberman: The New York schedule. When I go to New York, if you go to dinner at 5:30 p.m., you're kind of alone in the restaurant.
Dr. St-Onge: In Europe they eat very late often. I was on a Fulbright program last year in Spain, and I would joke with my colleagues there because they eat very late — even the children eat very late. They could have dinner at 10 or 11 p.m. and the children at 8 or 9 p.m.
Andrew Huberman: My dad's from Argentina. If you go to a restaurant in Buenos Aires at 9 p.m., you're not going to see many people. At 11 p.m. you'll see people in their 70s and 80s who are up early the next day. They nap in the afternoon. Very late-shifted culture.
Dr. St-Onge: There have been studies in Spain that have looked at timing of eating and its impact on weight management. I'm thinking of work by Marta Garaulet, where she showed that in her weight-loss program, participants who have their bigger meal — lunch — earlier in the day have better weight loss than those who have their lunch later in the day. So even in those cultures where they tend to eat late, they still find that eating earlier tends to be better for you.
Andrew Huberman: I was very relieved when Alan Aragon — who I consider one of the best public educators on the topic of protein and nutrition — reassured me that except in rare circumstances where people are really trying to optimize every bit of muscle protein synthesis, 95% of the effect of getting enough protein can be accomplished by having two meals, maybe a little snack. It can be evenly or unevenly distributed. The whole notion that you could only assimilate like 30 grams per meal is totally false — it turns out you can assimilate up to 100 grams. I find that very liberating. You could have breakfast and an early dinner with a snack in the middle. What I'm hearing from you, however, is that you really want to avoid the big late dinner. You just don't want to eat too close to bedtime.
Dr. St-Onge: Correct.
Medium-chain triglycerides
Andrew Huberman: What are some of the known benefits of MCTs? Where do you find them, and what brought you to them as a research topic?
Dr. St-Onge: This was a topic for my PhD dissertation. My PI got a grant looking at medium-chain triglycerides. What we did was use purified MCT oil — liquid oil that contains 8-carbon and 10-carbon chain fatty acids. Those are not very common in our general food source. It was purified extracted oil that we gave our participants. We had created a functional oil that also contained flaxseed oil to get some omega-3 fatty acids, and we had added plant sterols because that was a big focus of my lab at McGill — plant sterols for cholesterol reduction and reduced risk of cardiovascular disease.
The idea was to evaluate the impact on energy expenditure, because the way we process medium-chain triglycerides is different from how we process long-chain triglycerides — the 12, 14, 16 and up carbon chains. The medium-chain triglycerides travel directly to the liver, get metabolized, and we burn them off more readily than the long-chain triglycerides that travel in peripheral circulation and get deposited in adipose tissue.
In both men and women, there was an increase in the thermic effect of food — you burned slightly more calories from the meal that contained medium-chain triglycerides compared to the meal that contained standard fat.
For my PhD, the first study we did was in women, and we were trying to match the saturated fat content of the diets, because medium-chain fatty acids are by default saturated. So I said, okay, we're going to compare that to a saturated-fat-matched control. We used beef tallow. It was a lot of beef tallow. Participants were not happy with that diet. We put it on mashed potatoes. Half of the total fat of the diet came from either the medium-chain-containing oil or the beef tallow.
There's also this issue about the laxative effect of MCT oil. We had a few participants who initially felt a lot of GI disturbance from consuming MCT, because it was a lot. But it resolved after a few days. It was a four-week study, and after a few days no one dropped out for GI issues.
Beef tallow, because it has a lot of saturated fat, is solid at room temperature. So as soon as your food started to get a little colder, it would kind of gel on your plate. A couple of women felt it gave them a headache just from the smell of it.
Andrew Huberman: With the MCTs, there was a big significant increase in the thermic effect of food?
Dr. St-Onge: It was statistically significant. About 45 to 60 calories.
Andrew Huberman: Oh, I thought you were going to say a percent increase.
Dr. St-Onge: No. It's a small change, but if you're going to use this versus that, you're getting a little boost. If you repeat this a few times in a day — when we measured the thermic effect of food, we measured it only after one meal, but repeated over three meals per day over a certain period of time — we did find changes in body composition, improvements in weight status with medium-chain triglyceride consumption.
Andrew Huberman: Lean mass to fat mass. Interesting.
Dr. St-Onge: And then we did a follow-up weight-loss study with medium-chain triglycerides. This time it was just purified MCT oil versus olive oil, and we found greater weight loss with MCT.
Andrew Huberman: Based on what you're saying, it's reasonable if somebody wants to improve weight loss — I'm hearing a constellation of things: shift your meal timing to the first two-thirds or so of your day, which will also improve sleep, which will also improve appetite and satiety signals. What is it — a tablespoon or two of MCT per day?
Dr. St-Onge: Yeah, about that.
Andrew Huberman: In place of some other oil, not in addition.
Dr. St-Onge: Not in addition. Correct.
Andrew Huberman: Some ginger. Are they additive? Are they synergistic?
Dr. St-Onge: I think they could probably be additive because the impact is through different mechanisms. Obviously no one's tested that. It makes me think of David Jenkins and the portfolio diet, which actually made the New York Times in December. The portfolio diet was a diet he designed for maximal cholesterol reduction. It was initially designed to have four specific foods: high in soy protein, nuts, plant sterols, and soluble fiber.
Andrew Huberman: It's going to be a tough one to get past most of the American public. People hear soy. Nuts they like, but they're easy to overeat. They hear plant sterols and they're somewhere else.
Dr. St-Onge: This diet went head-to-head with a lipid-lowering agent — a statin. They had the same cholesterol reduction as a statin.
Andrew Huberman: As a statin. Interesting. They've expanded it?
Dr. St-Onge: They've expanded it to be more flexible. It's not just soy protein now — it also includes legumes. They've added monounsaturated fats, so olive oil.
Plant-based versus animal-based diets and satiety
Andrew Huberman: When I look at a diet like the portfolio diet, or the current food suggestions by the FDA emphasizing unprocessed and minimally processed food — I think that's a step in the right direction. The issue that always comes up for me is that in a more plant-based, grain-heavy, nut diet, it's very easy for people to overeat calories based on this amino acid protein foraging hypothesis — the idea that we eat until we get enough of the amino acids we want. A chicken breast or a couple of eggs is very satiating, whereas we can eat a lot of grains and nuts before we go, "Okay, that's enough." How do you ensure cardiometabolic health while quelling hunger? Do you see where I'm getting at? It feels like this is the contour of things — are we going to go mostly plants, grains, nuts, with lower saturated fat and improving blood lipids, or are we going to think more about protein and satiety?
Dr. St-Onge: I think there's no reason to pit one against the other. Having a diet that's more plant-based has higher volume — it's filling. It's hard to eat a lot of food if your food volume is high but doesn't provide as many calories. You'll get satiety from the food volume. And then putting in some nuts helps to prolong the satiety because you get some protein and some healthful fats. I'm not saying animal products are bad. I think they're important for a diet and for health. It's just a matter of portion size and making sure there's not an overemphasis on animal products over plant-based products, because we know that plant-based products are so much healthier in terms of heart health, reduction of type 2 diabetes, cancer risk, and other metabolic diseases.
Andrew Huberman: I love fruits and vegetables. I do eat meat — half Argentine, you know. And chicken. I'm not a big fan of fish. I keep working on this but can't quite get there. But I don't eat them in excess. The things that are very easy for people to overeat are starch-fat or starch-sugar-fat combinations. The brain and gut respond with signals that scream "more." It's very hard for people to do just a slice of pizza. The stop signals are all pushed down and the go signals are all go.
Dr. St-Onge: Reducing white foods as much as possible. The white flour, white rice, white pasta. If you're eating a slice of bread and it just dissolves in your mouth, it's not so good.
Andrew Huberman: If you look at the history of food in the United States, it's never been particularly healthy. The foods we consider American — hamburgers, hot dogs, French fries, corn dogs, fried chicken, donuts — we've never been healthy about food. People probably just moved a lot, ate less, smoked a lot more, which is an appetite suppressant. Maybe food volume was more in check, but the food was always pretty weak in terms of nutritional status except for fruits, vegetables, and some animal products.
Dr. St-Onge: I think portion size has a lot to do with it too. Moving from Canada to the US, you go to a restaurant and the portion sizes are so big. It would never have occurred to me to take home a doggy bag at a restaurant. Here it's kind of have to, or else you're throwing away half your plate.
Also, the foods are different in a way. When I moved to the US, the first thing the dietitian at my work told me was: do not buy bagged bread. She said, "You go to the grocery store, you go to the bakery section, they'll cut it up for you. Don't buy bagged bread." Apparently she was talking about too many additives, too much sugar. And then yogurt — I eat yogurt quite a bit, and the yogurt here in the US tasted sweeter to me. The same yogurt, same name, same everything — sweeter in the US than in Canada, and less sweet in Europe than in Canada and the US. Foods are formulated in different ways in different countries to appeal to the population of that country.
Andrew Huberman: We love our sugars and fats in the United States, and I think we've paid a substantial health debt as a consequence. With semaglutide and the other GLPs, a lot of people are finding it much easier to lose weight that they just couldn't lose before. They just could not control their appetite, and now they're just not as interested in these foods.
Dr. St-Onge: GLP-1s will do that. And I think things are changing. There are a lot more plain yogurt options than there were when I first moved to the US.
Andrew Huberman: There's been a lot of resistance — sociological resistance to people being healthy. There's this idea that if you're eating clean, you have an eating disorder. There's this notion that if you're going to be thoughtful about what you eat, or you're going to skip dessert, or until a few years ago if you're not going to drink alcohol, there's something wrong with you — that you're being restrictive somehow. In the United States, the social conventions built up around food and alcohol were pretty unhealthy. When people start making choices in the direction of their health, there's this quieter undercurrent of, "Are you really going to live like that?" But then you look at the health outcomes.
Culturally, until a few years ago, it was considered very not okay to say that obesity was a health risk. And now the open discussion about obesity and metabolic health as a real health risk — I think we're finally in the actual discussion that for a long time was kind of off-limits.
Industry-funded research and the snack chips study
Andrew Huberman: Speaking of which, there's a paper on your CV that I could not help but ask about: "Snack chips fried in corn oil alleviate cardiovascular risk factors when substituted for low-fat and high-fat snacks."
Dr. St-Onge: Yes.
Andrew Huberman: What? Tell me the data.
Dr. St-Onge: This was funded by Frito-Lay. At that time they had changed the oil they were using to fry their corn chips — Doritos, Fritos, Cheetos, and just plain chips. They had changed to corn oil, which is higher in polyunsaturated fats. The question was: does it make a difference? Is it going to improve health if people choose those snacks compared to other snacks?
We had three arms in that study. Each person went through each of the three arms for 25 days. The question was: if you have a choice for a snack and you're going to go to the vending machine, do you eat a low-fat high-carbohydrate snack, a high-fat higher-saturated-fat snack, or those chips? We gave two snacks a day for 25 days, rotating through four different chips. The better lipid profile was the one from the corn chips. They also had less lipoprotein little-a, which is another cardiometabolic risk factor.
Andrew Huberman: In the head-to-head comparison of seed oils with saturated fat, there are many studies showing that when you substitute saturated fat with seed oils, cardiometabolic risk factors go down. By the way, I avoid seed oils actively because I like olive oil and butter — mostly olive oil. I avoid seed oils. I don't like the way they taste. I love olive oil.
Dr. St-Onge: You have to make sure you're getting real olive oil, but that can be done.
Andrew Huberman: When you look at the studies that compare saturated fat to seed oils, you do see better outcomes for seed oils. But then there's this crowd that comes in and says, but that's on a backdrop of reasonably high carbohydrate intake. When you start replacing some of those carbohydrates with a lower-carbohydrate diet and increasing protein intake — not keto, but lower-ish starch and sugar — then maybe that balances out. But the big contention seems to be around the processing of these seed oils — this idea that when you take fats and combine them with carbohydrate and heat them up a lot, you create factors that are not good for the body. What is the evidence for or against that?
Dr. St-Onge: Different oils have different smoke points. Each oil should be used for its appropriate cooking process. You wouldn't put flaxseed oil and heat it up to a very high temperature. Oils that remain liquid at room temperature — that should be your barometer for what's better to use. I'm not saying people should avoid butter like the plague. All in moderation is okay.
Olive oil has a lower smoke point than other seed oils. Peanut oil, for example, has a higher smoke point, so you can fry in peanut oil. You wouldn't fry anything in olive oil. Some oils are more flavorful and will impart stronger tastes to different foods where they're not supposed to be.
Andrew Huberman: You're not seed-oil averse, nor are you pro-seed-oil personally?
Dr. St-Onge: No. The seed oil debate has been very contaminated by the issues I mentioned, but also because many processed foods contain seed oil — they're much less expensive than using grass-fed butter or olive oil. It's important to be nutrition-facts literate. When you're talking about processed foods, as much as possible, cooking at home. But a lot of people don't really know how to do that, feel they don't have the time for it.
Going to the grocery store and looking at the nutrition facts panel — comparing products to one another — and also knowing what's more important for your own health. What's relevant for my health may not be what's relevant for your health. Some people are very salt-sensitive. Some people are very active and need to replace salt, so salt is not an issue for them. Being able to know what to pay attention to, because otherwise it just gets overwhelming.
Industry funding, null results, and research integrity
Andrew Huberman: You mentioned the study was paid for by a company, and earlier you mentioned companies. I think this is an important issue. Anytime I've covered a paper, I always look at whether there are financial conflicts of interest. What's the difference between a company funding a study and a financial conflict of interest, if any? When a company funds research on something like the snack chips study, I think everyone would like to assume there's no explicit or implicit pressure for a particular outcome. Could you explain how this stuff comes about?
Dr. St-Onge: I'm glad you're asking that question, because people often have this knee-jerk reaction to industry-sponsored studies. As scientists, we do research to the best of our abilities. We draft the research question, get the data, analyze it, publish it. Some of the studies I haven't been able to publish have been funded by industry and have had null results.
Andrew Huberman: Null results. So you did a study, it was sponsored by industry, you didn't find any significant effect of the test product compared to the control.
Dr. St-Onge: We wrote the paper. We wrote the report. We provided it to our sponsor out of courtesy — this is the paper, we're going to submit it for publication. They gave us the green light to submit. That's in the contract — your right to publish. Because otherwise, why would you do research? There's no point doing research if you're not going to be able to publish it.
That one paper I'm referring to — I must have tried five different journals. The findings are not exciting. They're showing there's no effect on our outcomes. It got rejected, rejected, rejected, rejected. I'm pretty persistent, and I ran out of steam. So if I run out of steam, I can imagine so many other scientists who have no results have run out of steam much quicker than me.
Andrew Huberman: So that's a no-result issue. It's not necessarily unique to industry-funded studies.
Dr. St-Onge: Not unique. Industry-sponsored studies — we also get NIH reports of scientific misconduct. Reports of scientific misconduct can be found from NIH-sponsored studies where they find that the principal investigator falsified data. So to me, if you're not an honest scientist, it doesn't matter who's sponsoring your research.
Andrew Huberman: Doing science for any other reason than trying to find real answers is just insane. These things always come out in the wash.
Dr. St-Onge: It's a lot of work. And it never ends well.
Andrew Huberman: I'm hearing that negative outcomes are hard to publish. When you take on funding from a company to address a particular question about a product they sell, it sounds to me like you don't feel any pressure for a particular outcome. Why are they funding studies? Companies are selfish and they should be — they have shareholders. Why are they funding research?
Dr. St-Onge: They wanted to know if it had a health benefit so they could market a health benefit. And then if they don't find a health benefit, maybe they could switch to something else.
Andrew Huberman: I'm very sympathetic to the reality that there isn't a lot of research funding coming through NIH and NSF these days. It's always been very competitive. Are you taking money from companies to do this work because it's a great way to fund studies? If NIH had more money to study nutrition, I could imagine a world where you would just take money from NIH to do it. But sometimes there are specific foods and specific products that would be kind of hard to study without industry support because you need access to that specific food or product.
Dr. St-Onge: If you could get an NIH grant, that's the ultimate goal. Or USDA or other governmental grants. But sometimes there are specific products that would be hard to study without industry support.
Andrew Huberman: My fairly frequent check-in on what the now-being-revised NIH's stated goals include is creating a forum — even some incentive — for publishing negative or null results. Jay Bhattacharya, who's been on this podcast, has put that out publicly. We need those results. They're important. They steer people away from certain things that need to be steered away from. And it seems there's more and more interest in nutrition as a research topic. People are eating every day. There should be more federal funding for these things, and then there's no chance of bias.
Dr. St-Onge: I think people assume that if industry funded a study, especially on food, something's not to be trusted. I don't know why for food in particular. If you think about it — food and drug companies — drug companies do research on their own products. Most of the R&D for drug companies is done in-house. We don't see the null results. I actually would prefer if it took on a different shape.
Andrew Huberman: Outright scientific fraud — people making stuff up — is pretty rare.
Dr. St-Onge: Very rare.
Andrew Huberman: But I do think there are a lot of questions about people, because of the incentives to publish. When you run a lab, you want to create a culture where graduate students and postdocs feel very comfortable saying, "There's nothing here." You have a student who comes to you and says, "Hey, this is lower, this is better than this." And you look at the numbers and you say, well, it's 25 versus 27 and the standard deviation is 10. No — 25 is the same as 27. You have to make sure you teach well, so they know that even numerically different effects may not be statistically significantly different.
Dr. St-Onge: The ideal situation is when the student or postdoc doesn't believe their own results. They're like, "It's not really..." and then you have to convince them: actually, you have something interesting. That's a good situation.
Andrew Huberman: That's a good situation. And then eventually they're like, "Oh okay." I think this whole field of nutrition is contentious for some of the right reasons — it's so very important. And it's contentious also for a lot of unfortunate and unnecessary reasons. Among students and postdocs and the general public, when you interact, what are people most interested in with respect to nutrition? What's coming? What are your antennae picking up?
Dr. St-Onge: I think: what should I eat? Or have you heard about XYZ fad? Have you heard that whatever product cures everything in the world?
Andrew Huberman: Peptides are really big right now.
Dr. St-Onge: It's always something else. Very specific to a product.
Supplements, fiber, and whole foods
Andrew Huberman: Do you supplement your diet with minerals like magnesium or anything like that, or do you just rely on careful food choices?
Dr. St-Onge: I prefer careful food choices. I think it's more pleasurable to eat a complete food diet. That said, I think there are some people who may need to supplement their diets, but I think people should strive to get their nutrients from whole foods.
Andrew Huberman: Fiber recommendations are really growing. Many people's doctors are now telling them to take a little bit of psyllium husk. Doctors are prescribing supplemental fiber at a pretty high rate from what I understand.
Dr. St-Onge: That's interesting. People don't want to eat their fruits and vegetables, but there's so much more in them — all sorts of polyphenols, all sorts of non-nutrient components that themselves may have benefits for health that we don't fully understand yet, that feed your gut, that may enhance fiber's impact on health.
Andrew Huberman: Preaching to the choir. I love fruits and vegetables.
Closing reflections
Dr. St-Onge: I talk often about a vicious cycle where you don't sleep well, you don't eat well, and then that makes you not sleep so well. And I really hope for people to get into a healthful cycle — where you get good sleep, where you can make good food choices that then help you get better sleep, to keep propelling this cycle of better health.
Andrew Huberman: I love it. It's true integrative medicine and science. I can also attest that when you sleep well, you make better food choices. When you eat well, you sleep better. Thank you so much for coming, for taking time out of your schedule. I've learned a ton.
Dr. St-Onge: Thank you.