Fat City: Questioning The Relationship Between Urban Sprawl and Obesity

From the abstract:

"We study the relationship between urban sprawl and obesity. Using data that tracks individuals over time, we find no evidence that urban sprawl causes obesity. We show that previous findings of a positive relationship most likely reflect a failure to properly control for the fact the individuals who are more likely to be obese choose to live in more sprawling neighborhoods. Our results indicate that current interest in changing the built environment to counter the rise in obesity is misguided."

From the conclusion:

"It has been widely observed that urban sprawl is associated with higher rates of obesity. This observation has led many researchers to infer that urban sprawl causes obesity. The available evidence does not, in fact, permit this conclusion. The higher observed rates of obesity associated with urban sprawl are also consistent with the sorting of obese people into sprawling neighborhoods. In this paper we conduct an analysis which permits us to distinguish between these two possibilities.

Our results strongly suggest that urban sprawl does not cause weight gain. Rather, people who are more likely to be obese (e.g., because they have an idiosyncratic distaste for walking) are also more likely to move to sprawling neighborhoods (e.g., because they can more easily move around by car). Of course the built environment may still place constraints on the type of exercise that people are able to take or the nature of the diet that they consume. The key point is that individuals who have a lower propensity to being obese will choose to avoid those kinds of neighborhoods. What if they are not always able to avoid those neighborhoods because (say) their choice is constrained for financial reasons? Our results suggest that, even then, individuals adjust their exercise and diet to avoid gaining weight. Overall, we find no evidence that neighborhood characteristics have any causal effect on weight."

Contributing authors include: Jean Eid, University of Toronto, Henry G. Overman, London School of Economics, Diego Puga, Universitat Pompeu Fabra, Matthew A. Turner, University of Toronto

Thanks to Peter Gordon's Blog