Lack of physical activity found to be the most significant factor in contributing to childhood obesity. Researchers from the University of California, San Diego (UCSD) School of Medicine, in collaboration with investigators at San Diego State University, assessed the exercise and eating habits of nearly 900 children who were either at risk of becoming overweight or were already considered overweight. They also documented how often the children watched television.

Results of the study show a lack of vigorous physical activity is the main contributor to obesity for adolescents between 11 and 15 years old.

Researchers found children in the normal-weight group participated in two to four more minutes of vigorous physical activity per day than those in the at-risk and overweight group.

Researchers also found that fiber intake, and not fat calories, was more closely related to a child's weight. Normal-weight children consistently reported consuming more fiber than at-risk and overweight children did.

Also, researchers found overweight boys reported watching more minutes of television than normal weight boys.

Thus researchers conclude that insufficient physical activity and too much time spent on sedentary behaviors like computer games and watching TV may equal, and even exceed, diet quality as important contributors to overweight in adolescence.

"Diet, Physical Activity, and Sedentary Behaviors as Risk Factors for Overweight in Adolescence", Arch Pediatr Adolesc Med. 2004;158(4):385-390. doi:10.1001/archpedi.158.4.385.