A School-Based Intervention to Reduce Excess Weight in Overweight and Obese Primary School Students

Background: This study evaluated the effect of an intervention for reducing excess weight gain in primary school-age children in Tehran. Methods: A cluster-randomized controlled trial was conducted in 12 primary schools in Tehran. Three hundred thirty-four pupils, 167 in the intervention and 167 in the comparison group, determined to be overweight or obese based on World Health Organization standards, were recruited for the study. The intervention included nutrition education and increased physical activity (PA) for the pupils, lifestyle modification for parents, and a change in food items sold at the schools’ canteens. The entire intervention lasted approximately 18 weeks. Measures were taken before and immediately after the intervention. Results: The intervention significantly reduced body mass index Z-score and hip circumference ( p = .003 and p < .001, respectively). Waist circumference increased in both groups, but the increase was higher in the comparison group ( p = .001). No significant difference was seen in time spent on TV viewing between groups ( p = .08). Vigorous PA increased in the intervention group ( p < .001), while the comparison group showed an increase in moderate activity only ( p < .001). Energy intake increased significantly in the intervention group ( p < .001). Neither triceps skinfold thickness nor time spent on the computer changed in the intervention group ( p = .51 and p = .1, respectively), while they increased in the comparison group ( p < .001 and p = .004, respectively). Conclusion: The study provides a successful model for the implementation of similar interventions throughout the country.