Philadelphia, which has the highest obesity and poverty rates of the 10 largest cities in the US, is known for spearheading the fight against food deserts in the country, or areas where fresh produce isn’t available to buy in the near vicinity. But the $900,000 invested in new and improved grocery stores in the city may not be enough to curb obesity, a new study indicates (paywall). Researchers at the London School of Hygiene & Tropical Medicine and Penn State University report that an initial pilot study, which focused on the results from one of these grocery stores on the surrounding community, shows little effect. Without more research, they say, it’s difficult to know if these interventions are going to have any impact on obesity rates at all.
There’s reason to invest heavily in effective obesity intervention programs: By some estimates, US obesity-related medical spending increased costs by as much as $147 billion in 2008. The $400 million Healthy Food Financing Initiative—a federal project modeled after Philadelphia’s—is a reasonable effort compared to that sum. But are those eggs going in the right basket?
While the study only observed one store, checking in on local residents six months after its opening, the results are compelling. Only 27% of surveyed residents in the intervention area made the new supermarket their main store, and just over half of them used it for any shopping at all. And while residents perceived a greater availability of fresh fruits and vegetables, there was no significant increase in their daily intake of these foods, nor did the researchers see a significant decrease in body mass index (BMI).
As Wonkblog underlined back in 2012, the empirical evidence backing this method of obesity intervention is limited. This marks the first controlled US study of a subsidized market in a food desert, but a similar study in Leeds, England found that even when many residents switched to the new market, their eating habits barely changed. And a 15-year study of areas with “healthy” food options (fresh food market) versus “unhealthy” ones (fast food and convenience stores) found no direct connection between healthy food availability and health. While it seems logical that more widely available fruits and veggies would help foster healthy habits, a causal relationship has yet to be proven.
The authors aren’t suggesting that subsidized grocery stores should go away in the US, but to maximize their impact, the country’s federal initiatives should include other interventions as well. Marketing and branding need to focus on helping residents make the switch, the researchers say, and price incentives should be implemented to push shoppers into grabbing fresh food instead of low cost, high calorie items. With complementary efforts, they say, these grocery stores could make an impact—but simply helping them to open won’t be enough.