Fan He, an epidemiologist at Penn State University College of Medicine, and his colleagues found a strong correlation between the variation in sleep patterns among a group of teens and the amount of calories they consumed. And for every hour difference in sleep on a night-to-night basis over a week, for example, they ate 210 more calories—most of it in fat and carbohydrates. Those with uneven sleep patterns were also more likely to snack.
Previous studies have linked poor or disrupted sleep to obesity; people not getting enough shut-eye, for example, may experience changes in the hormones that regulate appetite and how well they break down glucose in their diet. Levels of the hormone leptin, for instance, drop in those who are sleep deprived, and less leptin prompts the body to feel hungry.
In the current study, however, all the teens got an average of seven hours a night, so it wasn’t as if some of the teens were sleeping for extremely long or short periods of time. Any metabolic changes they would have experienced due to their sleeping less than the recommended eight to nine hours would have been similar among the consistent and inconsistent sleepers.