Researchers collected data on 723 young people with a mean age of 14.7, studying how long they slept on weeknights and weekends, how often they reported sleep problems, and the foods and beverages they consumed.
The study was presented in Vancouver, British Columbia, at the annual meeting of the Pediatric Academic Societies.
The youths were asked on three separate occasions about foods and beverages they consumed; they also wore accelerometers on their belts to measure their activity levels.
According to study researcher Leslie A. Lytle, PhD, of the Seattle Children's Research Institute, shorter sleep duration was related to higher body mass index and also to the percentage of body fat.
This relationship, she says in a news release, seemed especially strong for boys and for middle school pupils, compared to youths in high school. In girls, only less sleep on weekends was related to a higher body mass index.
"Sleep has long been recognized as an important health behavior," Lytle says in the news release. "We are just beginning to recognize its relationship to overweight and obesity in children and adults alike."
The researchers say their study is one of the first to document an association between sleep duration and weight in adolescents.
Lytle also says the use of accelerometers and 24-hour dietary recalls was "unique" and a "real strength" of the study.