This review, published in 2009 by The Cochrane Collaboration, assesses the effectiveness of interventions designed to prevent obesity in children through diet, physical activity, and/or lifestyle and social support. The review includes 22 studies, ten long-term (at least 12 months) and twelve short-term (12 weeks to 12 months). The studies were heterogeneous in design, quality, target population, theoretical underpinnings, and outcome measures, making it difficult to combine findings statistically. Most studies were short-term, and those that combined dietary and physical activity approaches did not significantly improve BMI. However, some studies focusing on dietary or physical activity approaches showed small but positive impacts on BMI status. The review concludes that while many interventions are not effective in preventing weight gain, they can promote healthy diets and increased physical activity levels. Future research should assess broader population-level changes, such as improvements in food availability and safe spaces for physical activity, and should consider long-term health effects and costs.This review, published in 2009 by The Cochrane Collaboration, assesses the effectiveness of interventions designed to prevent obesity in children through diet, physical activity, and/or lifestyle and social support. The review includes 22 studies, ten long-term (at least 12 months) and twelve short-term (12 weeks to 12 months). The studies were heterogeneous in design, quality, target population, theoretical underpinnings, and outcome measures, making it difficult to combine findings statistically. Most studies were short-term, and those that combined dietary and physical activity approaches did not significantly improve BMI. However, some studies focusing on dietary or physical activity approaches showed small but positive impacts on BMI status. The review concludes that while many interventions are not effective in preventing weight gain, they can promote healthy diets and increased physical activity levels. Future research should assess broader population-level changes, such as improvements in food availability and safe spaces for physical activity, and should consider long-term health effects and costs.