This study used structural equation modeling (SEM) to examine associations between environmental factors and indicators of adiposity. We analyzed data from a cross-sectional Southeast Asian Nutritional Survey of 1,161 Thai children aged 7.0-12.9 years who were recruited by multi-stage sampling. Standardized questionnaires provided data on socio-economic, health status, and physical activity, while a 24-hour dietary recall provided dietary intake data. SEM analysis show that socio-economic, health status, physical activity, and nutrient intake were not associated directly with adiposity, but their relationship with adiposity was via the environment. This analysis confirms many relationships between possible causal factors and adiposity, and it enables insight into the complex mechanisms leading to higher body fat. As such, it could serve as a working model to combat the increasing prevalence of obesity (excess body fat) affecting many countries.