New research suggests that an early night may aid weight loss by curbing the urge to snack the next day.

Plamen Penev and colleagues enrolled 11 adults for their study to determine whether sleep restriction had any impact upon calorie intake. Participants slept at the University of Chicago's sleep research lab for two weeks, during which they were only allowed to sleep for 5 ½ hours each night. Then, three months later they returned for a second two-week stint, however this time they were allowed to sleep for 8 ½ hours each night. Participants were provided with meals and had unlimited access to snacks during both study periods.

Results showed that participants consumed, on average, 220 more calories – mainly in the form of carbohydrates, which were mostly eaten at night – the days after sleeping for just 5 ½ hours, than they did the days after sleeping for 8 ½ hours.

The authors concluded: “Recurrent bedtime restriction can modify the amount, composition, and distribution of human food intake, and sleeping short hours in an obesity-promoting environment may facilitate the excessive consumption of energy from snacks but not meals.”

Nedeltcheva AV, Kilkus JM, Imperial J, Kasza K, Schoeller DA, Penev PD. Sleep curtailment is accompanied by increased intake of calories from snacks. Am J Clin Nutr. 2009;89:126-133. doi:10.3945/ajcn.2008.26574