Efeito de interven？？es sobre o índice de massa corporal em escolares

objective: to evaluate the effect of intervention programs using nutritional education, physical activity or both on the reduction of body mass index in school-age students. methods: the systematic review with meta-analysis included randomized controlled studies available from the following electronic databases for the years 1998 to 2010: pubmed, lilacs, embase, scopus, web of science and cochrane library. the descriptors were: randomized controlled trial, overweight, obesity, body mass index, child, adolescent, physical activity, nutrition education and schools. a weighted average was based on the standardized means difference and used a 95% confidence interval. the inconsistency test was utilized to evaluate the heterogeneity of studies. results: initially, 995 studies were identified, of which 23 were included, and 3 meta-analyses were performed. isolated physical activity interventions did not present a significant reduction in bmi, with a standardized mean difference of -0.02 (95%ci: -0.08; 0.04). a similar result (n= 3,524) was observed in the isolated interventions of nutritional education, with a standardized mean difference of -0.03 (95%ci: -0.10; 0.04).when the interventions with physical activity and nutritional education were combined, the result of the meta-analysis (n= 9,997) presented a statistically significant effect in the reduction of body mass index in school-age students, with a standardized mean difference: -0.37 (95%ci: -0.63; -0.12). conclusions: the interventions that combined physical activity and nutritional education had more positive effects in the reduction of body mass index among school-age students than when they were applied individually.