Body mass effects of a physical activity and healthy food intervention in middle schools

Objective: To evaluate the effects of a 2-year middle school physical activity and healthy food intervention, including an environmental and computer-tailored component on BMI and BMI z-score in boys and girls. Research Methods and Procedures: A random sample of 15 schools with seventh and eighth graders was randomly assigned to three conditions: an intervention with parental support group, an intervention-alone group, and a control group. Weight and height were measured at the beginning and end of each school year to assess BMI and BMI z-score. A physical activity and healthy food program was implemented over 2 school years. Results: In girls, BMI and BMI z-score increased significantly less in the intervention with parental support group compared with the control group (p < 0.05) or the intervention-alone group (p = 0.05). In boys, no significant positive intervention effects were found. Discussion: This was the first study evaluating the effectiveness of an intervention combining environmental changes with personal computer-tailored feedback on BMI and BMI z-score in middle school children. After 2 school years, BMI and BMI z-score changed in a more positive direction in girls as a result of the intervention with parental support.