A meta‐analytic review of obesity prevention in the schools: 1997–2008

A meta‐analysis was conducted on school‐based interventions to reduce obesity in children. Sixty‐six ( k = 66, N = 31,059) comparisons from 40 published studies from 1997 through 2008 were included in analyses. Results indicated a significant effect for school‐based interventions with an overall weighted effect size of r = .05. Several moderating factors were examined to explain the heterogeneity in study outcomes. Interventions that were universal ( k = 37, r = .07), conducted in elementary schools ( k = 41, r = .06), implemented collaboratively ( k = 19, r = .12), primarily included children of Asian ethnicity ( k = 5, r = .30), encouraged nutritional change ( k = 28, r = .13), and sought to reduce sedentary behaviors ( k = 17, r = .15) were identified as more successful in reducing students' obesity‐related outcomes. Factors that resulted in negative effects for school‐based programs included interventions of short duration ( k = 11, r = −.04) and those that implemented system‐wide changes in nutrition ( k = 15, r = −.03). The variability in study effect sizes is discussed, and recommendations are made for future school‐based interventions targeting children.