There's a researcher at the RAND Corporation who has been building a reputation as a curmudgeonly skeptic when it comes to trendy ways to fight America's obesity epidemic.
First, Roland Sturm took aim at the idea that "food deserts" — areas without well-stocked grocery stores — cause unhealthy diets and obesity. His studies found that they do not. When Los Angeles decided in 2008 to ban new fast-food restaurants in some of the city's poorest neighborhood, Sturm was skeptical that it would help lower obesity rates.
Now Sturm, an economist, has taken a close look at what LA's fast-food ban has accomplished. He concludes in new paper published online by the journal Social Science & Medicine that there's no evidence it had any effect at all. In fact, obesity rates in South Los Angeles and other neighborhoods the law was aimed at increased faster than in other parts of the city or other parts of the county.
Advocates of the measure saw it as a powerful tool to help improve diets. Opponents, like fast-food chains, said "the sky is falling," Sturm tells The Salt. In reality, he says, "this has had no measurable impact."
In part, he says, it's because the fast-food ban took aim at an inconsequential target. It merely blocked new construction or expansion of "stand-alone fast-food" restaurants. Yet Sturm found that in South LA, the area covered by the ban, free-standing restaurants are relatively uncommon. They are far outnumbered by restaurants in strip malls and small food shops such as corner stores, none of which are restricted by the new city ordinance.
In the years since the ordinance was enacted, he says, the distribution of food outlets in this part of LA has remained more or less the same. Small corner stores are common, and so are fast-food restaurants in strip malls. No new free-standing fast-food restaurants have opened, but they were rare to start with.
Finally, he says, "social norms have not changed, either." Surveys of diet and obesity show no changes that can be attributed to the new fast-food restrictions. Fast-food consumption and obesity rates continued to increase in all areas of LA from 2007 to 2011-2012, and the increase was greatest in the areas affected by the fast-food restrictions. There was one notable exception: Soda consumption declined, but this was true across the city, not just in South LA.
Barry Popkin, a professor of global nutrition at the University of North Carolina, Chapel Hill, says he wasn't surprised at all by Sturm's observations. "That little ban was just too trivial," he tells The Salt. Many studies have now concluded that physical access to food "is less important than people think."
"Trivial" not how Kelly Brownell, a professor of public policy, psychology and neuroscience at Duke University, characterizes it, though. "I would not agree that this was a trivial measure, as it could be precedent setting, and in communities without many fast food restaurants, setting limits could help prevent problems," Brownell writes in an email. But he says he also wasn't surprised that the ban wasn't effective.
Sturm says he never set out to be an obesity policy killjoy. "I have no horse in that race, I care about getting facts right," he says. He admits, though, that the notion of supermarket proximity reducing obesity "always seemed fishy" even before he looked at the data.
And sometimes, he says, altering aspects of food environment can affect diets and obesity. He's come to the conclusion, for instance, that food prices matter. He's analyzed data from the U.S. and from South Africa, and in both cases, when fruits and vegetables were cheaper, people ate more of them, compared to less-healthy foods.
Popkin agrees. Diets won't change significantly, he says, "until we start changing the relative price of food," making nutritious food more affordable.