Story highlights One-third of U.S. adults don't get enough sleep, and roughly the same percentage are obese

Sleep-deprived participants in a study tended to eat more snacks with more carbohydrates, fat and protein

(CNN) If you crave chocolate or Cheetos after a hectic day, it may be because you're sleep-deprived, a new study suggests. Researchers have found that lack of sleep may lead to increased appetite and an affinity for unhealthy foods.

According to the Centers for Disease Control, one in three U.S. adults don't get enough sleep and roughly the same percentage are obese. Study author Erin Hanlon, a research associate at the University of Chicago, aimed to connect these two nationwide problems.

"Evidence from laboratory and epidemiological studies has started to consistently associate insufficient sleep with an increased risk of obesity," she said.

Lack of sleep can be a risk factor because it boosts hunger, due to the delicate balance between the nutrients consumed and the energy costs of staying awake, which remain generally the same whether you've had enough sleep or not.

Hanlon's study, published in the journal Sleep, compared 14 otherwise healthy young adults who had four nights of normal sleep (8.5 hours) with those with four nights of restricted sleep (4.5 hours). Both groups were provided with carefully prepared meals. On the final day, participants were given a healthy meal, followed by free rein at a snack bar containing tasty treats including cookies, candy and chips (what researchers dubbed "highly palatable, rewarding snacks"). Those in the sleep-deprived group tended to eat snacks with more carbohydrates and nearly twice as much fat and protein.

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