Macronutrient intake was measured using two 24-hour, multipass recall interviews conducted by trained staff. Details were collected about food items and portion sizes, as well as the timing, location, type, and preparation of each meal or snack. Nutrition data were analyzed using the Nutrition Data System for Research, a comprehensive nutrient database.

The authors noted that it is unclear why the association between shorter sleep durations and unhealthy dietary habits may be stronger in girls than boys. However, one explanation may be the increased propensity for female teens to engage in emotional eating.

"Further research is needed to understand how gender may modify the relationship between sleep, stress, metabolism and eating behaviors," Redline said.

The cross-sectional analysis did not allow for an examination of causality. However, Redline states that physiologic studies have identified numerous pathways by which sleep loss may promote weight gain. Reductions in sleep duration may alter metabolic rate and affect the production of leptin and ghrelin, two hormones that regulate appetite. Sleep restriction also may provide increased opportunities to eat, initiate stress responses that promote reward-seeking behaviors such as eating and reduce the physical and motivational drive to exercise.

A CDC study published last January in JAMA reports that the rate of obesity in U.S. adolescents between the ages of 12 and 19 years was 18.1 percent in 2007-2008. The authors concluded that the prevalence of high BMI in childhood has remained steady for 10 years and has not declined despite coordinated prevention efforts.

Redline believes that sleep may be the missing link in obesity interventions that focus only on diet and exercise. She suggests that improving sleep duration should be an essential component of obesity prevention and weight management programs.

Source: American Academy of Sleep Medicine