Purpose: To assess the effects of the Children’s Health, Activity and Nutrition: Get Educated! intervention on body size, body composition and VO2peak in a sub-sample of 10-11 year old children. Method: Sixty children were recruited from 12 schools (N= 6 intervention) to take part in the CHANGE! sub-sample study. Baseline, post intervention and follow measures were completed in October 2010, March-April 2011, and June-July 2011 respectively. Outcome measures were BMI z-score, waist circumference, body composition assessed using DEXA (baseline and follow up only), and VO2peak. Results: Significant differences in mean trunk fat mass (control 4.72 kg, intervention 3.11 kg, p = 0.041) and trunk fat % (control 23.08%, intervention 17.75 %, p = 0.022) between groups were observed at follow up. Significant differences in waist circumference change scores from baseline to follow up were observed between groups (control 1.3 cm, intervention -0.2 cm, p = 0.023). Favourable changes in body composition were observed in the intervention group; however, none of these changes reached statistical significance. No significant differences in VO2peak were observed. Conclusion: The results of the present study suggest the multicomponent curriculum intervention had small to medium beneficial effects on body size and composition health outcomes.