June 11, 2008 (Baltimore) -- Can't figure out why you can't keep your hand out of the cookie jar? It could be those long hours you've been keeping, a small study suggests.
Researchers have found that people who don't get enough sleep often indulge in excessive snacking.
The study is important because it attempts to tease out the reasons why sleep deprivation can lead to obesity, says Sanjeev Kothare, MD, a spokesman for the American Academy of Sleep Medicine (AASM). Kothare, a sleep specialist at Harvard Medical School, was not involved with the work.
"It suggests that high calorie intake from snacks plays a role," he tells WebMD.
The study involved 11 healthy men and women who agreed to enter the sleep lab for two 14-day periods. During one visit, they were allowed to sleep for only five-and-a-half hours each night. During the other, they slept for eight-and-a-half hours a night. During both visits, they could eat as much as they wanted, whenever they wanted.
Plamen Penev, MD, PhD, of the University of Chicago, headed the study. He presented the findings here at SLEEP 2008, the 22nd Annual Meeting of the Associated Professional Sleep Societies.
Results showed that when bedtimes were restricted to five-and-a-half hours, participants consumed an average of 1,087 calories a day from snacks alone. In contrast, they consumed 866 in calories from snacking when given eight-and-a-half hours to sleep.
The total number of calories consumed each day and the total weight gain was similar during both visits. But Kothare notes that participants were only studied for a few weeks. It's possible other changes would have been seen if they were followed longer, he says.
The AASM recommends that adults get between seven and eight hours of sleep nightly.