School-based obesity prevention program reduces harmful weight-control behaviors in adolescents

Sep 4 2007

Eating disorders among adolescent girls and boys can have substantial negative impact on their health and lead to dangerous weight-control behaviors, such as self-induced vomiting or abusing laxatives or diet pills to control weight.

The middle school age is a high risk time, especially for girls starting to engage in these dangerous weight-control behaviors that affect millions of Americans. Researchers at the Harvard School of Public Health (HSPH) set out to determine if an obesity prevention program called 5-2-1-Go! could reduce the risk of eating disorder symptoms and harmful weight-control behaviors in adolescents. The study showed that almost 4% of middle-school girls receiving only their regular health education began vomiting or abusing laxatives or diet pills, but just 1% of the girls in the 5-2-1-Go! program did so. The results showed no effect of the program on middle-school boys. The study appears in the September 2007 issue of Archives of Pediatrics & Adolescent Medicine.

“We are very encouraged by the results,” said S. Bryn Austin, assistant professor at HSPH and a researcher at Children's Hospital in Boston. “We are hopeful that carefully designed health promotion programs like this one may help us prevent both eating disorders and overweight at the same time. The protective effect that we found was strong and held up under two rigorously designed studies,” she said. The 5-2-1-Go! program (eat 5 servings of fruits and vegetables daily, limit screen time to no more than 2 hours a day, and get at least 1 hour of physical activity daily) includes the Planet Health curriculum, which was developed by HSPH researchers. It emphasizes eating a balanced diet, staying physically active and reducing the amount of time spent watching television. A previous study of the Planet Health curriculum had shown a protective effect on disordered weight-control behaviors in girls. The researchers wanted to see if that beneficial effect could be repeated in a larger study among a different group of schools.

The randomized, controlled study took place in 13 middle schools in Massachusetts between 2002 and 2004 and involved 1,451 sixth- and seventh-graders (749 girls, 702 boys). Six schools utilized the 5-2-1-Go! curriculum and seven utilized just their regular health education. The results showed a two-thirds reduction in risk of adopting disordered weight control behaviors among girls in the 5-2-1-Go! program.

The results suggest that it may be possible for school-based programs to help prevent obesity and eating disorder symptoms in adolescent girls. “Unhealthy weight loss behaviors and overweight are taking an enormous toll on the health of young people today,” said senior author Karen E. Peterson, director of the Program in Public Health Nutrition at HSPH and an associate professor at the School. “These problems may be linked in a number of ways, and the solutions are likely to be too. Approaches that foster healthy weights by changing lifestyles of youth in schools seem to be very promising.”

The authors note that further studies are needed to tackle the question of how other obesity prevention programs are affecting eating disorder symptoms in young people. “We found that our obesity prevention program was safe, that is, it did not worsen eating disorder symptoms and even protected against the development of eating disorder symptoms among girls,” said Austin. “The team of scientists and educators that created the program was also very careful not to single out or stigmatize overweight kids. Those involved with other obesity prevention programs in schools and communities around the country should look at the effects of those programs on eating disorder symptoms and weight-related bullying to make sure they're safe for the children.”