Falling short on shut-eye can make you consume more food throughout the day. In a 2012 Mayo Clinic study, individuals who cut their sleep time by an hour and 20 minutes a night consumed an average of 549 more calories the next day than those who caught their usual amount of Z’s. The results might have to do with the effect sleep has on our levels of ghrelin and leptin, two hormones that work together to stimulate and suppress appetite. What's more, feeling sluggish may cause you to turn to a snack for a quick pick-me-up. “An exhausted person will look for energy in food, and then it becomes a habit,” says Keri Gans, RD, author of The Small Change Diet.