March 23, 2011 -- People who get too little sleep tend to overeat, a Columbia University study suggests.
St-Onge and colleagues kept 13 men and 13 women in a controlled environment for six days on two separate occasions. During one visit, they spent nine hours a day in bed. On the other visit, they were allowed only four hours of bed time.
For four days, all of the men and women were kept on the same diet. On the fifth day they were allowed to eat anything they chose.
On that day, people gobbled about 300 more calories when they were sleepy compared to when they were well rested. Most of those extra calories came from fat, especially saturated fat.
Women were especially vulnerable to overeating when sleepy. Tired women ate 328.6 extra calories, while tired men indulged in 262.7 extra calories. Women were more likely to choose fatty foods when tired, but men tended to choose the same amount of fat.
With five extra hours to eat, didn't subjects simply use the extra time for an extra meal? St-Onge doesn't think so. Only seven of the 26 subjects ate after bedtime.
"Our data show that reducing sleep increases energy and fat intakes, which may explain some of the association observed between sleep and obesity," St-Onge and colleagues conclude. "If sustained, the dietary choices made by individuals undergoing short sleep would predispose to obesity and increased risk of cardiovascular disease."
St-Onge and colleagues presented their findings at the American Heart Association's Nutrition, Physical Activity and Metabolism/Cardiovascular Disease Epidemiology and Prevention conference, held March 22-25 in Atlanta.