Urban Sprawl
Urban sprawl is the outward expansion of a city and its suburbs into what was once rural land. Researchers have found that people who live in these areas of urban sprawl are more likely to be overweight than those living in the city.
For more information, consult these resources:
Active Living by Design: http://www.activelivingbydesign.org/
Center for Built Environment: http://www.cbe.berkeley.edu/
APA: Toxic America: http://www.apa.org/monitor/apr07/toxictoc.html
Sprawl City: http://www.sprawlcity.org/defining.htm