Research tells us that if we don't get enough sleep we could get fat. Lack of sleep has been linked to dysfunction of the appetite hormones leptin and ghrelin.
According to the American Journal of Clinical Nutrition, men in a study increased their food intake by more than 20 percent after just one night with too little sleep, as compared to their intake after a solid eight hours of sleep. If they were to continue that way, they would put on a pound of fat a week.
Dr. Michael Breus has been blogging about the importance of sleep, and now points to studies admonishing us to make sure we sleep soundly if we don't want our weight to get out of control.
"A study published in 2005, for instance, looked at 8,000 adults over several years as part of the National Health and Nutrition Examination Survey. Sleeping fewer than seven hours a night corresponded with a greater risk of weight gain and obesity, and the risk increased for every hour of lost sleep."
http://blogs.webmd.com/sleep-disorders/2010/05/sleep-it-off.html