There’s no scientific proof that sleep habits can lead to weight gain, but studies certainly point in that direction. Researchers have found that short sleepers (five hours or less a night) show a 32 percent gain in belly fat, as opposed to a 13 percent gain among those who sleep six or seven hours a night. Those who oversleep (eight or more hours a night) show a 22 percent gain in visceral fat.
“One of the more interesting ideas that has been smoldering and is now gaining momentum is the appreciation of the fact that sleep and sleep disruption do remarkable things to the body — including possibly influencing our weight,” says David Rapoport, MD, associate professor and director of the Sleep Medicine Program at the New York University School of Medicine in New York City.
A lot of this has to do with the hormones leptin and ghrelin, which influence our appetite and both of which are influenced by our sleep patterns. The two hormones work as checks and balances to control our hunger and make sure we don’t eat too much (or too little). One of the problems with sleeping too little is that it decreases the production and levels of leptin.
“When you don’t get enough sleep, it drives leptin levels down, which means you don’t feel as satisfied after you eat. Lack of sleep also causes ghrelin levels to rise, which means your appetite is stimulated, so you want more food,” explains Michael Breus, PhD, of the Atlanta School of Sleep Medicine.
Thus too little sleep, whether by design or because of a sleep disorder, can throw off the balance of the hormones that regulate our appetites and our eating. In short, we gain weight because we’re hungry and eat too much due to lack of proper sleep.
Doctors at the University of Chicago set about to research this phenomenon by studying 12 healthy men, who were subjected to two days of deprived sleep followed by two days of extended sleep. When sleep was restricted, leptin levels went down and ghrelin levels rose. The men’s appetite also increased, and their hunger for high-carbohydrate foods soared by a stunning 45 percent.
A Stanford University study was even more comprehensive, involving 1,000 volunteers who reported the number of hours they slept each night. Doctors then measured their leptin and ghrelin levels, along with their weights. Those who slept less than eight hours a night exhibited not only decreased leptin and increased ghrelin levels but also a higher level of body fat.
So if you’re fighting a bulging waistline, you may want to examine your sleep habits and make sure you’re getting a good night’s sleep. If a disorder is causing your sleep difficulties, then by all means seek professional help.