#16: Sleep & Weight Gain – Part 2

02/28/22 • 10 min

2 Listeners

Matt returns with Part 2 of his series on sleep and weight gain. This time around, he teaches us how a lack of sleep not only makes you eat more food, but changes what types of food you want to eat, and eat to excess.

First, Matt describes how underslept individuals that are limited to 4-5 hours of sleep for several nights will experience a 33% increase in the desire to eat obesogenic, sugary treats. In addition, they will suffer a 30% increase in craving for heavy-hitting carbohydrates, like pasta and pizza, and a 45% increased desire for salty snacks!

Matt goes on to explain that your brain plays a role in this sleep loss-weight gain equation. In one of his experiments, a group of normal, healthy-weight individuals went through the study twice: once when sleep-deprived and once after a full night of sleep. After each condition, the individuals were placed inside an MRI scanner and shown different food types, and asked to rate how much they wanted each food item.
What they found is that the sleep-deprived brain changed markedly, shifting to a pattern of activity associated with what is called hedonic eating, or impulsive eating. Specifically, the prefrontal cortex, which is responsible for impulse control, was shut down by lack of sleep. As a result, the very primitive deep brain regions that drive excessive appetite become hyperactive and hyper-responsive to highly desirable, unhealthy food items, such as ice cream and donuts, rather than nuts or leafy greens.

He also reveals that staying awake across the night doesn't burn vastly more calories. You only burn about an extra 140 calories by staying awake all night relative to being asleep, yet you will eat more than twice that amount more in calories when sleep-deprived. Plus, you are less active when sleep-deprived, so you don't burn off those calories.

Worse still, Matt tells us that dieting becomes ineffective without sleep: 60% of the pounds you will lose come from lean body mass (such as muscle), and not fat. Specifically, when you are sleep-deprived, the body becomes especially stingy with fat, stubbornly refusing to give it up. In other words, you end up losing what you want to keep, which is muscle, keep what you want to lose, which is fat. Also, inadequate sleep increases levels of cortisol, which also makes your body store food as fats.

Matt concludes with an optimistic note by highlighting the fact that getting enough sleep is a scientifically proven way to help you regulate your appetite and a healthy body composition (a little bit less painful than going to the gym!?)

Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.

The good people at InsideTracker are the sponsors of this week's episode, and they are generously offering 25% off any one of their programs for anyone who uses the above link. InsideTracker is essentially a personalized biometric platform that analyzes your blood and your DNA to better understand what's happening inside of you and also offers suggestions regarding things that you can do to better try and adjust some of those numbers, optimize them, and, as a result, optimize you.

So, make your way over to InsideTracker, and take advantage of this incredible deal on this valuable and remarkably convenient service. And, as always, if you have thoughts or feedback you'd like to share, please reach out to Matt on Instagram.

Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.

Previous Episode

#15: Sleep & Weight Gain – Part 1

Matt kicks off a two-part series all about sleep, eating, and weight gain.
He starts by introducing two appetite-regulating hormones: leptin and ghrelin. Matt explains how leptin sends a signal of fullness, to your brain. When leptin levels are high, your appetite is reduced, and you feel satisfied by the food you eat. Ghrelin does the exact opposite. It revs up your hunger, so when your ghrelin levels are high, you don’t feel satisfied by the food you ate, so you want to eat more.

Matt tells us that when you’re not getting enough sleep, the levels of these two hormones are affected in unfortunate ways, causing you to feel less full and more hungry. Specifically, sleep loss decreases leptin levels by 18%, yet increases ghrelin levels by 28%!
So when you are not getting enough sleep, the body losses the fullness signal AND suffers an increase in hunger levels. The combined consequences? Your appetite rockets up!

It’s also been discovered that levels of endocannabinoids --a class of cannabinoids we naturally produce ourselves -- increase sharply in response to a lack of sleep. As a result, your hunger levels increase even more (as you may know, cannabinoids are part of the reasons that cannabis gives you the munchies).

Adding up all of these effects, Matt describes how this lack of sleep causes people to consistently overeat. Usually somewhere between 250 to 400 extra calories each and every day!

Snacking also becomes a problem. For example, if you present a group of people with a large meal of over 1,000 calories, then give them the option to keep snacking, under-slept individuals will continue to snack, consuming an additional 200 to 300 calories relative to those who’ve been getting a full eight hours of sleep.

This all begs the question: is there a reason why your hunger goes into overdrive when you are under-slept? Matt explains one plausible theory from an evolutionary perspective, based on the fact that when animals are in a starvation state, the brain keeps them awake longer so they can forage further. Therefore, when the brain doesn’t get enough sleep, it thinks we may be in a state of starvation and increases our desire for food.

Finally, notes what's coming in part two: that insufficient sleep not only increases how much you eat but changes your food preferences, and changes how your bodies deposit the extra calories we take on as our hunger increases, relevant to body fat accumulation.

Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.

The good people at Athletic Greens are the sponsors of this week’s episode, and they are generously offering three benefits for anyone who uses the above link for their first order: 1) a discount on your order, 2) a one-year free supply of vitamin D, and 3) five free travel packs. Athletic Greens is a nutrition drink that combines a full complement of antioxidants, minerals, and biotics, together with essential vitamins. Matt’s been using it for several years now, first because he’s serious about his health and uses it as a full nutritional insurance policy, and second, because Matt did his research on the science and ingredients in Athletic Greens and thinks it’s science and scientific data that can be taken as ground truth.

So, make your way over to Athletic Greens, and take advantage of this incredible deal. And, as always, if you have thoughts you’d like to share, please reach out to Matt on

Next Episode

#17: Sleep is Bloody Remarkable #1

Matt has a special announcement this week: a new recurring type of episode called, ‘Sleep is Bloody Remarkable’. This series of episodes will share fascinating facts about sleep that will blow your mind! In the premier episode, Matt focuses on something truly (bloody) remarkable: half-brain sleep, or unihemispheric sleep.
Unihemispheric sleep is the phenomenon of when one hemisphere of the brain is awake, while the other sleeps. Matt goes on to discuss how the two sides of the brain rotate their sleep roles, such that after a set period of time, the side that got to undergo sleep first wakes, so that the other half of the brain gets its needed opportunity for sleep.

Whales and dolphins are great examples of half brain sleepers. They need to maintain movement in their underwater environment. Half-brain sleep allows them to still do this while still getting plenty of NREM slumber (just one half of the brain at a time). Birds are also capable of half-brain sleep. Birds use unihemispheric sleep for survival purposes, although for different reasons. Birds use it to keep one eye on things, literally!

When birds land as a flock, the birds on the farthest left and right sides - the sentinels, as it were - undergo unihemispheric sleep, to keep one eye open for threat detection on their respective side (180 degree views on the left and right). The result being, combined, the entire flock gets full 360 degree panoramic threat detection. Indeed, all of the rest of the birds are allowed to sleep with both hemispheres i.e., full brain sleep.

The poor birds on the sides don’t actually get the chance to come into the middle of the flock, it seems. Instead, to get equal sleep on both sides of the brain, when one hemisphere has fulfilled its sleep need, these birds will rotate 180 degrees, and switch sides of the brain that is sleeping. Bloody remarkable!

We humans undergo our own rendition of unihemispheric sleep...sort of =) In an unfamiliar location, such as a hotel room, humans keep one of their hemispheres on guard in this potentially dangerous context. Meaning, one half of the brain does not go into as deep NREM sleep, almost as if it is remaining semi-conscious. Matt also notes that half-brain sleep only happens during NREM sleep. When all species go into REM sleep, both sides of the brain sleep. There is no unihemispheric dream sleep, it seems.

Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.

The good people at Athletic Greens are the sponsors of this week’s episode, and they are generously offering three benefits for anyone who uses the above link for their first order: 1) a discount on your order; 2) a one-year free supply of vitamin D; 3) five free travel packs. Athletic Greens is a nutrition drink that combines a full complement of antioxidants, minerals and biotics, together with essential vitamins. Matt’s been using it for several years now, first because he’s serious about his health and uses it as a full nutritional insurance policy, and second, because Matt did his research on the science and ingredients in Athletic Greens and thinks it’s science and scientific data that can be taken as ground truth.

So, make your way over to Athletic Greens, and take advantage of this incredible deal. And, as always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram.