Background. Programs to improve cardiovascular health in schoolchildren need careful scientific evaluation.Method. In a randomized controlled trial of nutrition and fitness programs over a period of about 9 months, 1,147 10- to 12-year-olds from 30 schools were allocated to one of five health programs: fitness, fitness + school nutrition, school-based nutrition, school + home nutrition, home-based nutrition, or a control group. Nutrient intake, fitness, anthropometry, blood pressure, and blood cholesterol were measured before and after intervention.Result. Fitness increased and diastolic blood pressure and triceps skinfolds decreased significantly for girls in the fitness groups. Baseline consumption of sugar, fat, and fiber was outside national guidelines; blood cholesterol exceeded recommendations in one-third of children. In girls, fat intake decreased significantly in the two home nutrition groups and fiber intake increased in the school + home nutrition and fitness groups. Boys in the fitness, fitness + school nutrition, and school + home nutrition group reduced sugar intake. Change in sugar intake correlated negatively with change in fat intake in both boys and girls.Conclusions. Teacher-implemented health packages are feasible with minimal training but programs should differ between boys and girls. Fitness programs were more successful than nutrition education particularly in girls. Clearer nutrition messages should prevent reciprocal changes in sugar and fat. For girls, the 3 mm Hg reduction of diastolic blood pressure, less obesity, and increased fitness could translate into a substantial reduction in cardiovascular risk in adult life. (C) 1995 Academic Press, Inc.