Duke 2008 | ASHE | Equity and Efficiency in Health and Healthcare

One often mentioned explanation of the significant rise in obesity in the U. S. is an increasingly sedentary lifestyle and an often cited cause of this lifestyle change is urban sprawl. However, whether urban sprawl is a cause of a sedentary life is unknown as the interpretation of this relationship is confounded by self selection of residents. This paper addresses the ?selection? issue by using exogenous variation in urban sprawl caused by the original plan of the Interstate Highway System. By combining data from the National Health Interview Survey (1976-2001) and the U.S. Census (1970-2000), this paper assesses the extent to which urban sprawl has contributed to the increase in obesity. Empirical estimates show that a 10 percentage point decrease in the proportion of population living in dense areas leads to about a 1.5 percentage point increase in the obesity rate. If the average metropolitan area had not experienced the exogenous decline in population density, the estimates thus indicate that the rate of obesity would have been reduced by about 18%.