Here's yet another reason to get enough Zzzs: Sleeping less than you should at night could spur you to consume unneeded calories, a small new study suggests.
Researchers from the University of Colorado at Boulder found that people tend to consume more calories from after-dinner snacks if they sleep fewer than five hours a night for a week. The findings are published in the journal Proceedings of the National Academy of Sciences.
"When people are sleep-restricted, our findings show they eat during their biological nighttime when internal physiology is not designed to be taking in food," study researcher Kenneth Wright, the director of the university's Sleep and Chronobiology Laboratory, said in a statement.
The study, which was conducted along with researchers from the University of Colorado Denver's Anschutz Medical Campus, included 16 young, healthy adults. The study participants stayed at the University of Colorado Hospital, where they were in "sleep suites" that provided quiet, light regulation and trackers to see how much oxygen and carbon dioxide was breathed in and out.
At the start of the study, researchers had study participants sleep as long as nine hours a night for three nights. They also fed them calorie-controlled meals (enough to maintain their weight) during this time.
Then, the participants were split up into two groups. The first group was only allowed to sleep for five hours for five days, while the other group was allowed to sleep for nine hours for five days. Both groups of participants were allowed access to bigger meals and unlimited snacks at any hour of the day. Snack choices ranged from fruit to chips.
Then, after five days of this eat/sleep assignment, they switched spots, so that the group that was only allowed to sleep five hours was then allowed to sleep nine hours, and vice versa.
Researchers found that those who were only permitted five hours of sleep a night burned slightly more energy -- 5 percent more -- than those who were allowed nine hours of sleep. But they also consumed 6 percent more calories, ate smaller breakfasts, and consumed more in evening snacks (they consumed more calories from evening snacks than they did from any single meal during the day).
"I don't think extra sleep by itself is going to lead to weight loss," Wright said in the statement. "Problems with weight gain and obesity are much more complex than that. But I think it could help. If we can incorporate healthy sleep into weight-loss and weight-maintenance programs, our findings suggest that it may assist people to obtain a healthier weight."
Just last month, a small study in the journal Psychoendocrinology showed further evidence that sleep deprivation can make people more apt to eat bigger portion sizes. And a study presented last year at a meeting of the american Heart Association showed that sleep deprivation is associated with consumption of an extra 500 calories a day.
For more potential effects of not getting enough sleep, click through the slideshow: