For whom and under what circumstances do school-based interventions to promote energy balance behaviors work?

The aim of a review recently published on-line by Mine Yildirim et al. in the International Journal of Pediatric Obesity was to systematically review the results and quality of studies investigating the so-called moderators of schoolbased interventions aimed at energy balance-related behaviors (diet, phsyical activity and sedentary behaviors). Such moderators tell us for whom and under what circumstances these interventions are effective or not. In total 61 original studies were included in our review. Gender, ethnicity, age, baseline values the different behaviors, weight status and socioeconomic status were the most frequently studied potential moderators of intervention effects. Gender was found to be a consistent moderator of intervention effects, i.e. school-based interventions appear to work differently for boys and gilrs, and our review evidence suggests that such interventions generally work better among girls.  For the other potential moderators, there were just not enough studies of good enough quality to draw further conclusions. Consequently, our review revealed that there is still lack of insight into what interventions work for whom and that future studies should do better jobs to explore if and how intervention effects differ among different target group segments.