Here’s What Happens to Your Appetite When You Miss Out on Sleep
Just five nights of sleep deprivation can mess with your hunger cues and metabolism, making you feel less satiated after eating and hindering the clearing of fat from your bloodstream, new research published in the Journal of Lipid Research suggests.
This can lead to overeating, which can set you up for weight gain.
The hit your metabolism takes from bad sleep—whether we’re talking about not enough time spent sleeping, waking up too much, or missing out on deep ZZZs—has been covered in numerous studies, particularly the way sleep disorders can mess up your hormones and your metabolism.
Now, there’s another reason to add to the mix: Just a few days of sleep deprivation can make you feel less full after eating—possibly leading to more snacking and overeating in general—and also mess with the way your body metabolizes fat, causing it to be stored in the body more easily, new research published in the Journal of Lipid Research suggests.
In the small study, 15 healthy men in their 20s checked into a sleep lab for 10 nights. For five of those nights, they were kept awake well into the evening so that they didn’t spend more than five hours in bed. For the remaining nights, they were able to sleep as normal.
After four nights of sleep restriction, researchers gave participants a late-night meal of chili mac and cheese to represent a calorically dense, high-fat dinner. Later in the study period, when they were allowed to sleep for a longer time period, they also got a high-fat meal before bed.
Although both types of meals were similar in terms of fat content, participants reported feeling less satiated on the nights they were sleep deprived.
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When researchers looked at blood samples taken throughout the study timeframe, they also found that the participants’ bodies were more sluggish in clearing out the fat—also known as lipids—from their bloodstream after a meal than they were on longer-sleep nights. That’s a problem, because excess amounts of lipids can cause the fat to deposit in your artery walls, increasing risk of heart disease, and can also prompt storage of that fat, causing weight gain.
“This shows that restricting sleep, even just for several days, changes how satisfied we are by a meal, even one that is very calorie-dense,” said study co-author Orfeu Buxton, Ph.D., a professor in the department of biobehavioral health at Pennsylvania State University. He told Runner’s World, “This might cause people to eat far more than they actually need. Also, restricting sleep changes how our body processes what we eat in ways that promote weight gain and diabetes in the long term.”
The study has its limitations—particularly in terms of the small sample size, brief research period, and similar participant group. For example, it’s unknown if a similar effect would happen for women and/or older people as well, and what may occur with those who have metabolic disorders or high cholesterol.
Also, lead author Kelly Ness, Ph.D., at the University of Washington, told Runner’s World that the highly controlled environment of the study makes it an imperfect model for the real world, and it’s possible that more recovery time—for example, catching up on sleep for more than five nights after shorter-sleep nights—might have a beneficial effect that reduces the impact of occasional sleep deprivation.
But even with those caveats, Ness says the research is one more piece of evidence that long-term incidence of short sleep can increase the risk of obesity, diabetes, and or other metabolic diseases.
She adds that at the very least, skip the temptation to have a high-fat meal just before bed when you know you’ll be short on sleep. Even if it is chili mac—it might not satisfy you as much as you think.
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