Do the Suburbs Make Us Fat?
“But numbers are numbers.” [1] This statement from a recent editorial sums up what is likely the typical reaction to a new study claiming that urban sprawl contributes to obesity among suburbanites. It seems like there has to be more going on, but who can argue with a scientific study published in an academic journal? As is often the case with these “shocker” studies, what the research actually reveals and how those results are portrayed in the media can lead to two very different impressions.
In the latest issue of the American Journal of Health Promotion, a roughly ten-page article lays out the case that there is a significant relationship between housing density and problems such as obesity and hypertension. [2] At approximately the same time, Smart Growth America and the Surface Transportation Policy Project released a more media-friendly report co-authored by one of the journal article’s authors and using the same results. [3]
The premise of these publications is that people who live in suburban communities are more likely to live sedentary lives than their urban counterparts. They drive from door to door, rather than walk or bike, for groceries, school and work. Moving out of the city now means packing on the pounds, and the numbers are hard to argue with. With the facts established, the studies’ recommendation — more densely planned communities — appears to be a practical response.
The missing ingredient is context. First, we must understand what the studies actually state. The authors estimate, for example, that an average person in the most dense and compact county would be six pounds lighter than someone in the least dense county. Changing one’s diet even slightly can achieve similar results, and regardless, the relationship between health outcomes and the weight difference attributed to sprawl is weak at best.
Second, the studies seem to ignore larger cultural changes. With rising incomes have come greater levels of home and car ownership. Along with this, so has the demand for at-home entertainment — DVD’s, computers, video games and the like. Combine this with an increase in the preference for higher-calorie food such as fast food and pizza, and the waistlines of Americans will expand regardless of their location in the metropolitan area. This weight gain has actually been a well-established trend over the past ten years, one for which the “sprawl factor” is insufficient to explain. [4]
Finally, the image the authors have crafted is one of static communities. In contrast, one of the most striking population trends of the 1990s was the densification of suburban areas and the loss of population within urban areas. [5] Again, this suggests that there is more at work in America’s battle of the bulge than simply that there are too many people living in detached homes with a yard. Until city leaders address issues of crime and poor public services under their jurisdiction, for instance, people will likely continue to make the tradeoffs necessary to move out. [6]
One could easily get the impression that these studies are an effort to save us from ourselves. Seeking to dictate neighborhood form to prevent a small weight increase is, however, a tall order for even the most committed social engineer and probably the least cost-effective method to address America’s growing waistlines.
Notes
[1] Editorial, “The new ‘urban sprawl,’” The Toledo Blade, 3 September 2003. Available at: http://www.toledoblade.com/
[2] Reid Ewing, Tom Schmid, Richard Killingsworth, Amy Zlot and Stephen Raudenbush, “Relationship Between Urban Sprawl and Physical Activity, Obesity and Morbidity,” American Journal of Health Promotion, Vol. 18, No. 1, September/October 2003. Available at: http://www.smartgrowthamerica.org/.
[3] Barbara A. McCann and Reid Ewing, Measuring the Health Effects of Sprawl (Washington, DC: Smart Growth America and the Surface Transportation Policy Project, September 2003). Available at: http://www.smartgrowthamerica.org/.
[4] Wendell Cox, “Sprawl and Obesity in Ohio: What’s All the Fuss About?” (Columbus, OH: The Buckeye Institute, September 2003). Available at: http://www.buckeyeinstitute.org.
[5] Samuel R. Staley and Matthew Hisrich, Urban Sprawl and Quality Growth in Ohio (Columbus, OH: The Buckeye Institute, December 2000). Available at: http://www.buckeyeinstitute.org.
[6] Joshua C. Hall, Samuel R. Staley, Matthew S. Hisrich and Aengus L. Barry, Education Empowerment Zones: Revitalizing Ohio’s Cities through School Choice (Columbus, OH: The Buckeye Institute, March 2003).
