I tend to emphasize that while walkable living is probably thinning, one shouldn’t underestimate the extent to which the correlation between obesity and driving is a result of self-selection of the obese into auto-oriented lifestyles. But hey, walkable living is probably thinning:
Increasing the availability of public transit systems is one among a number of modifications to the built environment that offers opportunities for increasing physical activity and reducing the prevalence of obesity and its associated problems. In a study published in the August issue of the American Journal of Preventive Medicine, researchers from the University of Pennsylvania, Drexel University and the RAND Corporation found that construction of a light-rail system (LRT) resulted in increased physical activity (walking) and subsequent weight loss by people served by the LRT. These findings suggest that improving neighborhood environments and increasing the public’s use of LRT systems could improve health outcomes and potentially impact millions of individuals.
That’s via Freakonomics. I don’t support improvements in urban policy because they’re healthy; I support them because they make good economic sense. But for people making decisions about where to live, this is a data point worth keeping in mind.