 Data will be collected in 12 countries 500 children per site from five major regions of the world Eurasia Africa, Europe, Latin America, North America, and the Pacific. Cross-sectional evaluations will be undertaken in each country. The physical characteristics of the children will be directly measured in order to classify their body weight and adiposity status, and physical activity and dietary patterns will be measured with the most objective techniques currently available. A concise set of environmental measures that are feasible, valid and meaningful across the international settings included in this research will also be employed. The results of this study will provide a robust examination of the correlates of obesity and weight gain in children, focusing on both sides of the energy balance equation. The results will also provide important new information that will inform the development of lifestyle interventions to address childhood obesity that can be culturally adapted for implementation around the world. 