"Do I look fat?" The statement that elicits a roll of the eyes from a husband or boyfriend has a more tragic tone when it comes from the mouth of an 11-year-old girl. The sad fact is that obesity rates among children and adolescents are growing, while girls remain under intense social pressure to be thin. That combination is a recipe for eating disorders, including bulimia and anorexia. Eight percent of middle school girls reported taking laxatives or vomiting to control their weight in the past year. Harvard researchers looked at whether a program to teach children about nutrition, with the purpose of reducing obesity, could also lower the number of girls with unhealthy eating patterns.

What the researchers wanted to know: Do school-based obesity-prevention programs reduce disordered eating in middle school girls?

What they did: The researchers went to middle schools, enrolling about 500 girls in the study. In half of the schools they ran a two-year program called Planet Health, which integrates information about nutrition and fitness into the normal curriculum. One lesson, for example, asks students how the industrial revolution might have changed the amount of physical activity in people's daily lives. Both before and after the program, the students were given a questionnaire that asked them about their health, including their use of dieting, diet pills, or vomiting to control weight. Students in the middle schools that did not run the program responded to questionnaires at the same time as the other students.

What they found: Between the time of the first and second questionnaires, 2.8 percent of the girls who were involved in the Planet Health program said they started using diet pills or vomiting to control their weight, compared with 6.2 percent of the girls who were not exposed to the program. The researchers say this is the first study they know of to show that an obesity-prevention program can also help young teens learn to control their weight in a healthy way, rather than turning to behaviors that can lead to serious illnesses such as bulimia nervosa.

What it means to you: Programs that teach adolescents about proper nutrition and fitness may have the added benefit of helping girls stay away from dangerous dieting techniques. Around the country, schools are using lessons to teach children how to eat and exercise, and this study shows it may be important for more than just preventing obesity.

Caveats: The number of girls who started using diet pills or vomiting was small in both programs (fewer than 10 in each), so another study should be done to make sure these numbers aren't a fluke. Also, three of the five authors of this paper helped develop the curriculum that was used in the schools, so they could be biased as to how well it works.

Find out more: Planet Health is a project of the Harvard School of Public Health.

The American Academy of Family Physicians has a site for teens about eating disorders.

Read the article: Austin, S.B. et al. "The Impact of a School-Based Obesity Prevention Trial on Disordered Weight-Control Behaviors in Early Adolescent Girls." Archives of Pediatrics and Adolescent Medicine. March 2005, Vol. 159, No. 3, pp. 225-230

Abstract online: http://archpedi.ama-assn.org