Why You Make Worse Food Choices When You're Tired | Dr. Marie-Pierre St-Onge & Dr. Andrew Huberman

Sleep Loss & Overeating

00:00I think there's some subconscious need to to eat more when you're sleepd 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. People know that you eat it wakes you up in a way.

00:13You know, neuronal signaling that that enhances uh pleasurable and reward centers of the brain where you know when also fatigue sits in and now it's like do you really want to have this conversation with yourself about what to choose at the buffet table?

00:32you know, 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 consumption with um with sleep restriction and it's been reproduced. There's been so many studies uh 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 3500 excess calories more or less for a pound of body weight and then you start when

01:12people accumulate that over time if they're in a night shift condition or new parents or tending to a sick relative were just final exams like it it's a real thing. It's a real thing. Uh Neymar Kovson in uh 2022 published a paper where uh they had sleep restriction about 5 hours per night versus 7 and 1 half hours per night for two weeks and participants gained half a kilo in a twoe period.

01:36So you do nothing and you just you know sleep less and gain gain almost a pound in two 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.

01:58And

Role of Cortisol

02:00and the the just so story was always that uh 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?

02:15Is it really a way of of I'm not saying just inducing stress because 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.

02:32So 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 short sleep. Tell me more about that. I'm fascinated by circadian rhythms and cortisol. So, what does what does that what does that mean?

02:47There was no difference between the two conditions, the adequate sleep or short sleep on cortisol levels for 5 days of sleep restriction at basically 4 hours a night. So, cortisol is still peaking at in the in the morning, still dropping in the evening.

03:00Yeah. Wow. That's very surprising to me. I don't know I don't know if it's the context of you know being in a lab where everything's safe taken care of for them there's nothing outside to aggravate this so I don't know maybe when you're in the context of sleep restriction but also dealing with your daily life you 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 you know the the added stressful Oh, so the message is if you suffer less than adequate sleep, get someone to take care of everything else.

03:40You better be in a spa. Exactly. Exactly. No, I and I'm not challenging the result. I just find it really interesting. I would have thought that basil cortisol levels would would go ary. Well, in that study also, we didn't see any effect on glucose or insulin.

03:55Nothing. Nothing. The curves were superimposable. while 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

Metabolic Impacts in Daily Life

04:16a 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, poor diet that then triggers a worsening and may be compounded by the lack of sleep, even worsening of of those cardioabolic outcomes because we did a follow-up study to this uh this severe sleep restriction study.

04:49So 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 uh risk of type two diabetes.

05:14So, because we had seen that food choices were different, that they ate a diet that was higher in calories, higher uh in fat and saturated fat, we thought maybe if you're in a free living situation, that's when you start to see those cardio metabolic outcomes because it's compounded by maybe uh more sedentary behavior and alterations in in uh food choices and and diet.

05:46So the follow-up study then was to recruit good sleepers, people who sleep at least seven hours per night, verified by ecttoraphy, 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 that you get an hour and a half reduction in sleep."

06:16Because when we screen people to sleep at least 7 hours per night, they sleep about 7 and 1/2. 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

Long Term Health Consequences

06:36yeah 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 restrict iction compared to adequate sleep.

06:55We saw insulin sensitivity was reduced. It was worse actually in post-menopausal women compared to premenopausal women. We saw blood pressure uh was increased. Uh so those cardabolic outcomes were adversely impacted in freel mild sustained sleep restriction for 6 weeks.

07:146 weeks was something else also. It was it was tough.