Tuesday, July 06, 2010

Built environments impact on obesity through food, not fitness.

Chalk up another causal win to food in the battle of what's responsible for our current obesity epidemic - this time in the arena of built environment.

Built environment is the term given to the neighbourhood you live in. It has to do with things like walkability, parks, bike paths, sidewalks and all the various and sundry that city planners can do to try to shape your use of where you live.

Built environment is also a hot button issue at obesity conferences with researchers trying to find ways to get people moving more through smarter urban planning.

My belief is that casually moving more doesn't matter too much with regards to obesity. There's simply no amount of sidewalks or bike paths or beautiful parks that you could put in a neighbourhood to help with the issue of obesity because obesity is primarily about energy intake, not energy output, and really no amount of leisurely strolling is going to negate our horrendously calorific food environment.

But built environment does matter. What matters about the built environment though is food and how close you are to it, and what type it is.

In a study published this month in the Journal of Planning Education and Research Samina Raja et al looked at the influence of built and food environments on 172 women's BMIs in Erie County New York between 1999-2004.

What did they find?

1. The more restaurants within walking distance the higher the BMI (p=0.037).

2. The closer you live to a healthful food destination (supermarket), the lower the BMI (p=0.025).

3. Walkability didn't make one whit of difference.

Interestingly the authors listed the fact that they didn't know the types of restaurants as a limitation and suggested that there might be healthier ones. I'd argue, with exceedingly rare exceptions, restaurant food, regardless of whether it's sit down, stand up, casual, or fancy, has non-intuitively, astronomically large numbers of calories.

Ultimately what matters isn't the sidewalks, it's where they take you.

Raja, S., Li Yin, ., Roemmich, J., Changxing Ma, ., Epstein, L., Yadav, P., & Ticoalu, A. (2010). Food Environment, Built Environment, and Women's BMI: Evidence from Erie County, New York Journal of Planning Education and Research, 29 (4), 444-460 DOI: 10.1177/0739456X10367804