The Child and Adolescent Trial for Cardiovascular Health (CATCH), the largest and most comprehensive school-based intervention yet undertaken, targeted diet and physical activity behaviors as secondary outcome variables (Box 7-2). This randomized trial involving 96 elementary schools did not result in significant changes in body weight; however, significant changes did occur in the school food environment and in reported dietary intakes by students (Luepker et al., 1996). Compared to control schools, the fat content of meals at the intervention school meals was substantially lowered, and intervention students’ reported dietary fat intake was significantly reduced relative to that of control students. Also, as noted below in the discussion on physical activity, the percentage of physical education classroom time with moderate to vigorous physical activity increased in the intervention schools. The researchers speculated that the reasons for the lack of changes in physiologic risk factors may be related to the growth and development stage of the students or to the relatively low magnitude of the changes in food intake and physical activity levels (Luepker et al., 1996).
Pathways, a large, multicomponent school-based intervention designed as an obesity prevention study, was conducted among third- to fifth-grade American-Indian children in reservation schools over a 3-year period (Caballero et al., 1998). Pathways did not significantly affect body-weight change, but significant intervention-related changes were observed for some dietary and physical activity behaviors, including lower fat intake and higher self-reported physical activity levels in the students in the intervention schools (Caballero et al., 2003). The goal of the food service intervention—to reduce the fat content of the school meals—was achieved. Both the CATCH and Pathways interventions show the feasibility of making positive changes in the school food environment, but also the challenges still to be faced in designing primary obesity prevention interventions in schools. As pointed out by the researchers in the Pathways study, restriction of energy intake is not an option in schools because there are students who are below the fifth BMI percentile, additionally, the school meals programs have to meet minimum mandatory levels for calorie content (Caballero et al., 2003).
Several other school-based intervention studies have shown significant effects on body-weight outcomes; these studies tested multicomponent interventions not limited only to targeting dietary change. Planet Health reported reductions in the prevalence of obesity among girls only (Gortmaker et al., 1999), and the Stanford Adolescent Heart Health Program observed reductions in BMI, triceps skinfold thickness, and subscapular skinfold thickness among boys and girls (Killen et al., 1988).
Overall, school-based interventions, both multicomponent and single component, have produced healthful food choices among students. Envi-