Lack of sleep makes you prone to overeating, according to a new study.

RODALE NEWS, EMMAUS, PA—Lack of sleep has been linked to depression, cardiovascular disease and other health problems. Studies have found a connection between lack of sleep and weight gain, too, and new research explains why. In the study, people who got half the recommended amount of sleep durng one night took in significantly more calories the next day.

THE DETAILS: In a small study carried out in France and reported in the American Journal of Clinical Nutrition, researchers measured the food intake of 12 men on two separate occasions. On one of them, the men were allowed to sleep for eight hours the night before having their food intake monitored the next day. The second time, the men were only allowed to sleep for four hours before having their food monitored the next day. Food-intake results: The men ate an average of nearly 600 more calories—a 22 percent increase—after the four-hour night of sleep compared to after the eight-hour sleep. It's a convincing demonstration of how sleep and weight gain are related.

WHAT IT MEANS: The study is important because it shows that sleep loss—if it happens often enough over the long term—could increase your risk of gaining weight thanks to increased calorie intake. But why exactly would sleep loss have this effect on eating the next day? In part, it could simply be a case of your system getting out of whack, suggests lead study author Laurent Brondel, PhD, of the Centre European des Sciences du Gout in Dijon, France. “Traditionally, the human environment was very different,” explains Brondel. “There was less access to food, people were more active, and they generally slept longer. During the last century, this has changed in most parts of the world.”