It seems everyone is looking for a culprit when it comes to childhood obesity: fast food, sugary drinks, super-sized everything. But it turns out part of the blame may lie with the simple matter of turning out the lights and rolling into bed.

That’s according to the results of a study conducted by Chantelle Hart, associate professor of public health at Temple’s Center for Obesity Research and Education (CORE), published this week in Pediatrics. The study, entitled “Changes in Children’s Sleep Duration on Food Intake, Weight, and Leptin,” is the first known study to examine the impact of sleep on children’s eating behaviors by manipulating the amount of sleep that study participants were able to get.

Thirty seven children, ages 8 to 11—27 percent of whom were overweight or obese—participated in the study over a three week period. For the first week, the children were asked to sleep their typical amount. Next, during the second week, the group was randomized to either reduce or lengthen their sleep time; participants completed the opposite sleep schedule during the third and final week of the study.

The results were conclusive: During the week that the children increased their sleep, they reported consuming an average of 134 fewer calories per day, weighed a half pound less, and had lower fasting levels of leptin, a hunger-regulating hormone that is also highly correlated with the amount of adipose tissue, when compared to the week of decreased sleep.

“Findings from this study suggest that enhancing school-age children’s sleep at night could have important implications for prevention and treatment of obesity," said Hart. "The potential role of sleep should be further explored."

So what’s next? Hart is working on a study funded by the National Heart Lung and Blood Institute of the NIH using a brief behavioral intervention to get kids to increase their sleep to determine if there are significant changes in eating, activity behaviors and weight status.

While it is still early in the testing, Hart hints that the intervention looks promising:

“Given all of its documented benefits, in many ways, you can’t lose in promoting a good night’s sleep.”

Hart conducted the research while at the Miriam Hospital and Alpert Medical School of Brown University. Funding was provided by a grant from the American Diabetes Association.

-Susan Vogel