Fast Food

Garbage In, Garbage Out: Fast Food Edition

The notion that fast food causes obesity is an article of faith for many food policy advocates. No doubt, the meals that are commonly served up at fast food restaurants — loaded with lots of calories, fat, sugar, and salt — can give you a magic carpet ride to obesity.

But then some are tempted to make the leap to simplistic ideas about zoning fast food restaurants out of neighborhoods. Los Angeles tried it in 2008, with a ban on new or expanded fast food restaurants in South LA. It started as a moratorium for a year, was extended, and then became permanent in 2011. But there’s no evidence to suggest that this action is doing anything other than fattening the profits of approximately 1,000 restaurants that are already there.

To justify such initiatives, advocates rely on linking the concentration of fast food outlets to poor nutrition and obesity in the neighborhoods they serve. Numerous studies find a correlation. Daniel Kruger and colleagues just published another such study in the American Journal of Health Promotion this week. This study, like others that have come before, has two problems. First, it relies on an association to suggest causality. Other studies have been done that point out the the problem with this — confounding factors are in play here. Second, the study relies on self-reports for both BMI and dietary habits. Self-reports for these data have been shown to be so unreliable as to render the results meaningless.

Meanwhile, in the American Journal of Public Health this week, Donglan Zhang and colleagues point to a more productive strategy. Through an agent-based simulation model, they found that zoning policies would have no significant impact. But they did find substantial potential for improving the visibility of positive social norms for nutrition. These findings echo findings published last fall by Michael Bader in Health & Place. They found that the neighborhood retail environments are complex ecosystems. So simplistically focusing on fast food outlets in isolation could lead to false conclusions. Healthy retail environments might have more fast food outlets, but nonetheless lead to lower obesity rates.

“Politics is the art of looking for trouble, finding it everywhere, diagnosing it incorrectly and applying the wrong remedies.” — Groucho Marx

Click here to read more on fast food zoning, here to read the study by Kruger et al, here to read the Zhang study, and here to read the Bader study.

Fast Food, photograph © Brian Wallace / flickr

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