Sleep deprivation and food purchases

Another study linking diet and sleep. This article describes research with normal weight, healthy men after one night of sleep deprivation. Researchers gave the men about $50.00 to buy groceries the morning after a normal night's sleep or a night of sleep deprivation. After the night of sleep deprivation, the men bought more food and food that had more calories. The sleep-deprived men also had elevated levels of ghrelin, a hormone involved in appetite, but this did not correlate with food purchase behavior.

The take home message was to not go grocery shopping after a night of sleep loss. I wonder if the effect would taper for the many Americans who have chronic, partial sleep deprivation?

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.