An interesting study in the American Journal of Clinical Nutrition about sleep deprivation and calorie consumption. Thirty men and women in their 30's and 40's, all of about normal weight, lived and slept in a research center during 2 different 5-night periods. During one of the visits, participants were allowed to sleep 9 hours each night. During the other 5-night visit, the participants were only allowed to sleep 4 hours per night. During both 5-night periods, they were fed strict diets for the first four days, then allowed to eat whatever they wanted on the fifth day.

The results showed that regardless of the sleep schedule they were on, the participants burned a similar amount of calories, about 2600 calories per day. In those that slept only four hours, they fed themselves about 300 more calories on average on that final day than when they slept 9 hours.

The researchers propose that sleep is involved in how your body manages hormones that are involved in hunger and food choices when you're hungry. The difference between 9 and 4 hours is dramatic, and I wonder if people would eat more calories if they got 5, 6, 7, or 8 hours of sleep? More studies are needed to answer this and other questions about the relationsip between sleep, sleep deprivation, and obesity.