Study ties lack of sleep to obesity

December 13, 2004 LAS VEGAS - Sleep scientists say the less you sleep, the more likely you are to become overweight. In a study released in mid November at the North American Association for the Study of Obesity (NAASO)'s Annual Scientific Meeting, researchers found that people who slept less than four hours per night were 73% more likely to be obese than those who slept from seven to nine hours per night. People who got five hours of sleep per night were 50% more likely to become obese. And people who got six hours of sleep were 23% more likely. "The results are somewhat counterintuitive, since people who sleep less are naturally burning more calories," lead researcher James Gangwisch, a post-doctoral fellow in psychiatric epidemiology at Columbia University said in a press release. "But we think it has more to do with what happens to your body when you deprive it of sleep as opposed to the amount of physical activity that you get. Other studies have shown that leptin levels decrease and grehlin levels increase in people who are sleep-deprived, leading to increased appetite and consumption." Why would that happen? According to Gangwisch, one possible answer can be found in looking back at our early forebears. "The metabolic regulatory system may have evolved to motivate humans to store fat during summer months when the nights are shorter and food is plentiful, which was a survival mechanism for the body to prepare for the dark winter months when food would not be as plentiful," said Gangwisch. "As a result, sleeping less could serve as a trigger to the body to increase food intake and store fat."