11 studies (five randomized controlled trials, three non-randomized controlled trials and three meta-analyses) met inclusion criteria for this question.

Five controlled trials found that school-based interventions utilizing a variety of methods were effective in improving markers of obesity in children. One meta-analysis found that nutrition and physical activity interventions in school-based settings can result in substantial reductions in weight. One meta-analysis found no significant changes between children who received school-based obesity interventions and those who did not.

Two controlled trials found that interventions delivered in community or home settings, utilizing a variety of methods, were effective in improving markers of obesity in children.

One controlled trial and One meta-analysis examined specific interventions for child obesity. Presentation of appropriate portion sizes may discourage over-consumption at meals. One meta-analysis found no association between consumption of sugar-sweetened beverages and BMI.

Minimal research was identified in this age group regarding prevention of obesity.  Further research is needed to determine the effectiveness of specific interventions to prevent obesity.

• Grade I means there is Good/Strong evidence supporting the statement;
• Grade II is Fair;
• Grade III is Limited/Weak;
• Grade IV is Expert Opinion Only;
• Grade V is Not Assignable.
• High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
• Moderate (B) means we are moderately confident in the effect estimate;
• Low (C) means our confidence in the effect estimate is limited;
• Very Low (D) means we have very little confidence in the effect estimate.
• Ungraded means a grade is not assignable.

Three studies (one randomized controlled trial, two non-randomized controlled trials) found that interventions including school-based programs and individualized dietary counseling were effective in reducing risk factors for cardiovascular disease, especially in girls. Effective interventions included both nutrition and physical activity components as well as a strong emphasis on parental involvement in the intervention. The studies demonstrated improvements in nutrition knowledge, blood pressure, weight and BMI. Further research is needed to determine the optimal methods for preventing cardiovascular disease in children.

• Grade I means there is Good/Strong evidence supporting the statement;
• Grade II is Fair;
• Grade III is Limited/Weak;
• Grade IV is Expert Opinion Only;
• Grade V is Not Assignable.
• High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
• Moderate (B) means we are moderately confident in the effect estimate;
• Low (C) means our confidence in the effect estimate is limited;
• Very Low (D) means we have very little confidence in the effect estimate.
• Ungraded means a grade is not assignable.

Three studies (two randomized controlled trials, one non-randomized controlled trial) found that childhood nutrition interventions resulted in improvements in one or more of the following risk factors for type II diabetes: glycemic control, BMI, body composition, and nutrition- and physical activity-related behaviors. Interventions were delivered through school-based and community-based programs, and encompassed nutrition education, physical activity, and development of skills for self-management of health behaviors. 

Further research is needed regarding the prevention of type II diabetes in children as well as the long-term effects of childhood interventions on adult diabetes prevention.

• Grade I means there is Good/Strong evidence supporting the statement;
• Grade II is Fair;
• Grade III is Limited/Weak;
• Grade IV is Expert Opinion Only;
• Grade V is Not Assignable.
• High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
• Moderate (B) means we are moderately confident in the effect estimate;
• Low (C) means our confidence in the effect estimate is limited;
• Very Low (D) means we have very little confidence in the effect estimate.
• Ungraded means a grade is not assignable.