Losing sleep at night affects our behavior the next day in lots of ways, not the least of which is what we eat. Anyone who’s crammed a donut into their mouth to help them wake up after a rough night can attest to this phenomenon, but now we have a study to prove it. A new meta-analysis finds that partial sleep deprivation—missing a few hours of sleep per night—is linked to taking in significantly more calories the next day. And the bigger issue might be that the connection also seems to work the other way: Poor food choices during the day may affect how well we sleep. So it’s a bit of a vicious cycle we’re up against, and it seems to be mainly be happening in the brain.
The new study, in the European Journal of Clinical Nutrition, looked back at 11 smaller studies, which together included 172 people. The participants were all deprived of sleep to varying degrees for relatively short periods of time (one day to two weeks), and their calorie intake the next day was measured. It’s important to point out that these were all short-term studies, so we don’t know how the results might change over the long term.
People who were sleep-deprived consumed, on average, about 385 calories extra per day. The extra calories were mostly in the form of increased fat; and the participants also tended to eat less protein when they lacked sleep. Interestingly, carbohydrate consumption didn’t change. What also didn’t change were the activity levels of the sleep-deprived participants. And when energy intake increases but activity stays the same, we gain weight.
This isn’t the first time we’ve seen the connection between sleep deprivation and poorer eating the next day. A Mayo Clinic study a few years ago found that when people are sleep deprived, they make different (worse) food choices than when they’re well rested. In fact, in that study, participants ate about 550 calories more when they got two-thirds the amount of sleep as controls who slept a full night. Others have found similar connections.
Why would sleep, or lack thereof, influence food intake? The authors of the new study say that sleep deprivation may alter how the hunger and satiety hormones function, as some studies have suggested. But it may be even more likely that sleep deprivation changes our motivation to seek food and feel rewarded by it. Some research has found that certain areas of the brain related to motivation and reward are activated more in response to food when participants were sleep-deprived. Which means that that donut looks a lot more appealing when we’ve had a rough night than when we’re well rested, and the satiation it provides is that much stronger.
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“Sleep, of course, is vital to health in its own right. In addition, it affects weight in a variety of ways,” says David L. Katz, founding director of the Yale University Prevention Research Center, and contributor at FORBES. “The psychological effects of sleep deprivation influence eating, as suggested here. Sleep disturbances also disrupt our hormones in ways that can lead not only to weight gain, but fat deposition in the most harmful places. Lack of energy from lack of sleep is likely, over time, to sabotage a commitment to exercise, too.”
And perhaps the larger problem is that the connection also seems to work the other way: A study earlier this year found that what we eat can affect our sleep quality. When people ate food of their own choosing, as opposed to healthier, researcher-designed meals, it took them significantly longer to fall asleep at night (29 minutes vs. 17 minutes).
So it may really be a two-way street, with sleep affecting food choice and food choice affecting sleep. And this probably shouldn’t surprise us.
“Whether we treat it accordingly or not, health is holistic,” says Katz. “Pain can affect sleep; sleep can affect mood; mood can affect exercise; exercise can affect weight; and weight can affect pain. Often the only way to deal effectively with any of these, and other, health issues is to address them all. Unfortunately, models of clinical care that do so are very much the exception rather than the rule.”
It’s becoming clear that weight—and in fact health overall—is about a lot more than just the physical stuff. The behaviors we engage in—taking care of our stress levels and staying socially connected, for instance—are at least as important for our health over the long run as the physical endeavors. And sleep is certainly right up there.
“Sleep is on the short list of lifestyle practices most important to every aspect of health,” says Katz. “Perhaps this reminder of a direct link to excess calories will help it get the respect it deserves.”
Source : Forbes
