The effect of participation in school-based nutrition education interventions on body mass index: A meta-analysis of randomized controlled community trials

► This MA shows that nutrition education is effective to reduce BMI among students. ► Intervention time is more relevant than the intervention component. ► The estimated effect size for the eligible RCTs was − 0.33 kg/m2. ► Among RCTs with more than one intervention year the effect size was − 0.48 kg/m2.