It's clear that activity is good for kids, lead author Naiman A. Khan told Reuters Health. But he was surprised at just how much of a difference this program made.
"We saw their overall body fat, abdominal fat go down, and in the absence of the program kids actually increased in overall body fat," said Khan, from the University of Illinois at Urbana-Champaign.
For their study, the researchers randomly divided 220 kids ages eight and nine into two groups. One group participated in the FITKids program, which includes 70 minutes of moderate to vigorous physical activity five times per week for nine months, and the other group did not.
In the exercise group, kids did 20 to 25 minutes of health-related fitness activities plus 50 minutes of organized noncompetitive games meant to keep their hearts beating at 55 to 80 percent of their maximum heart rate.
That's higher than most previous exercise studies have aimed for, which may be why this study got such good results, according to Dianne Stanton Ward of the University of North Carolina Gillings School of Global Public Health in Chapel Hill.
Ward studies obesity prevention in children. She was not involved in the new research.
Image: Girl exercising, via Shutterstock