Fangshan Active Nutrition Initiative

The goal of this study is to evaluate the effectiveness of a school-based weight management intervention delivered through a digital platform (WeChat) in preventing excessive weight gain and improving health behaviors in school-aged children in Fangshan District, Beijing. The main questions it aims to answer are: Does the intervention group show a significantly lower mean increase in BMI, body fat percentage, and waist circumference compared to the control group? Does the intervention group show a significantly lower obesity rate and new obesity incidence compared to the control group? Does the intervention group show significant improvements in healthy eating, sedentary behavior, sleep, physical activity, and physical fitness test scores compared to the control group? Researchers will compare children in intervention schools (who receive the multi-level intervention targeting students, families, and schools, supported by a digital platform for behavior monitoring and feedback) to children in control schools (who do not receive the intervention during the study period). Participants in the intervention group will: (1) attend 10 student health education sessions; (2) have their physical activity at school increased to 60 minutes/day of moderate-to-vigorous activity; (3) have parents attend health education lectures and use a WeChat platform to receive health information, log child health data, and receive automated feedback; (4) have their height, weight, waist circumference, and body composition measured monthly by school health staff; and (5) be followed with assessments at 6, 12, and 24 months.

Inclusion Criteria: * Schools will be selected based on the consent of primary leadership, demonstrated cooperation, and availability of necessary personnel (e.g., school health professionals). * Classes will be limited to grades 2 and 3, with teachers showing strong willingness to collaborate. * Both parental informed consent and child assent are required for participation. Exclusion Criteria: * Schools will be excluded if they cater to special populations (e.g., schools for children with disabilities), are involved in other obesity-related interventions within the specified timeframe, or plan to close or relocate within two years. * Children will be excluded if they have histories of major organ diseases (e.g., cardiac, pulmonary, hepatic, or renal conditions), special diets (e.g., vegetarian), pathological eating disorders, physical limitations affecting activity, or obesity due to endocrine disorders or medication side effects.