This chapter concerns the analysis of geographic and contextual effects on health behaviors related to energy balance, such as diet, weight, and physical activity. We adopt a broad definition of the environment to include not just ambient exposures to toxins, meteorological conditions, or other traditional foci of environmental sciences but also the built, economic, social, and policy aspects of the environment. The chapter includes a selective review of research in this area concerning urban sprawl and obesity, built environment and physical activity, social context and energy balance, and the food environment. We then focus on ongoing challenges to advances in the analysis of contextual effects, including discussion of confounding self-selection as a barrier to causal inference, variable selection and spatial scan statistics, and the general problem of incorporating maps into research on health behavior variables. Experimental and longitudinal designs have not been applied extensively in this field and are required to examine causal associations and to quantify which types of interventions are likely to have the largest effect in specific situations.