Aspects of what researchers and planners call the “built environment” are important determinants of physical activity for both children and adults and therefore of rates of childhood obesity (Black and Macinko, 2008; Booth et al., 2005). The built environment encompasses all of the man-made elements of the physical environment, including buildings, infrastructure, and other physical elements created or modified by people (e.g., sidewalks, streets, trails, bicycle lanes, parks, playgrounds), as well as the functional use, arrangement in space, and aesthetic qualities of these elements (e.g., zoning, neighborhood design, mixed-use development) (IOM, 2005). Handy (2005) categorizes these elements as follows:
Land use—the location and intensity of activities, including residential, commercial, and institutional activities, and the design and arrangement of the buildings and sites that house them.
Transportation systems—the physical layout and design of roads, sidewalks, bike paths, and other transportation infrastructure, and their function and appearance.
The “social environment” is just as important to physical activity. It includes such elements as family, friends, place of employment, home, culture, socioeconomic status, and neighborhood. The social environment also encompasses neighborhood reputation, defined by perceived safety and social nuisances, as well as social support and social capital (Black and Macinko, 2008). For example, parental modeling of and support for participation in physical activity (e.g., by providing transportation and purchasing equipment) has been associated with higher levels of physical activity in children (Hoefer et al., 2001; Sallis et al., 2000).
However, the environment in which some children live often makes it difficult to engage in physical activity. Many neighborhoods lack open space, parks, recreational facilities, or sports fields. Neighborhood features that encourage physical activity are consistently associated with decreased weight. Among these factors, mixed land use, access to fitness facilities, and neighborhood “walkability” have all been linked to higher levels of physical activity and lower body weight (Black and Macinko, 2008). These are all aspects of the built environment.
The built environment’s influence on childhood obesity is determined by its effect on physical activity levels and also, as the previous chapter explains, its effect on healthy eating. It can promote or deter physical activity, such as organized active recreation, active commuting, and unstructured play. Various elements