Lack of sleep can make you fat

Adolescents who stay up late gain more weight compared to those who slumber soundly, the study, first of its kind to document an association between sleep duration and weight in adolescents, points.

“Sleep has long been recognized as an important health behavior,” study’s lead researcher, Leslie A. Lytle, from the Center for Child Health, Behavior and Development at Seattle Children's Research Institute notes.

“We are just beginning to recognize its relationship to overweight and obesity in children and adults alike.”

Facts of the study
723 adolescents with an average age of 14.7 years were included in the study. Each participant was questioned about his or her sleeping pattern on weekdays and weekends, how often they experienced sleep problems, if any, and their eating habits measuring their caloric intake over three days.

For seven days, participants were made to wear an accelerometer, a highly specialized device that measures activity level by monitoring movement on three different planes; side-to-side, up and down directions.

Throughout the study, researchers also measured the participants' weight, body mass index (BMI), a ratio of a person's height and weight, and percentage of body fat.

Findings of the study
Shorter sleep durations were linked to higher BMI in boys, but not girls, researchers found. For boys, as sleep hours decreased, their body fat percentage and BMI increased. Likewise, those who slept adequately had a lower body fat percentage and BMI, researchers indicated.

Also, the relationship was especially strong for middle-school students than for those in high-school, researchers found.

However, in girls, only less sleep on weekends was related to higher BMI, Dr. Lytle pointed.

The research was presented at the Pediatric Academic Societies (PAS) annual meeting in Vancouver, British Columbia, Canada.