Getting too little sleep can have all kinds of negative consequences, including making you cranky and impairing your driving. A growing body of evidence suggests an addition to that list might be in order: Lack of sleep might also make you fat.
The intriguing prospect that sleep duration may play a role in how much we weigh has researchers busily conducting studies to tease out the potential relationship between shut-eye and BMI.
Although it might seem intuitive that under-sleeping leads to overeating, science hasn’t yet found a direct cause-and-effect relationship between lack of sleep and being overweight. “There is a very, very strong link,” says Jim Hill, director of the Colorado Nutrition Obesity Research Center at the University of Colorado and a spokesman for the American Society for Nutrition. “People with sleep problems tend to have obesity. Why? That’s where the research is.”
In one of the latest studies, Marie-Pierre St-Onge of the New York Obesity Nutrition Research Center at St. Luke’s-Roosevelt Hospital found that sleep-deprived people tend to burn the same number of calories — in her study, about 2,600 per day — as people who enjoy a full night’s sleep. But her research, published in the August issue of the American Journal of Clinical Nutrition, found that sleep-deprived subjects consumed about 300 more calories per day (2,800 vs. 2,500) than the well-rested subjects. Because it takes just 3,500 calories to add a pound to your body, St-Onge says, “if people kept that up for a while, it would add up really, really quickly.”