Sam Seitz

People in low-income and predominantly minority neighborhoods tend to enjoy much lower access to healthy food options. In Washington, D.C., for example, around 11% of the city is classified as a food desert, though this partly depends on how one defines a food desert. Unsurprisingly, this lack of access is a problem in rural America as well, and it makes it more difficult for residents to conveniently acquire high-quality, healthy food. Not unreasonably, many assume that the solution to this vexing problem is, in fact, quite simple: increase the supply of nutritious food through direct government programs or through subsidies. This would be ineffective, though, as food deserts are actually a demand problem, not a supply problem. In other words, there are shortages of quality eateries and grocery stores because people don’t want healthy food.

The evidence on this is absolutely overwhelming. For example, a recent study by Allcott, Diamond, and Dube conclusively debunks the simplistic notion that lack of access, rather than lack of demand, explains poor health outcomes in food desert neighborhoods. The study specifically examines two types of within-household change to examine the effects of food deserts. First, the authors examine household food purchases after a store opens up in a food desert. Second, they examine household food purchases after a family moves from a food desert to an area with plenty of access to healthy groceries. What they find is that high-income households buy a much higher percentage of healthy food than low-income households, and this pattern holds irrespective of where these households are located. So, when a grocery store opens in a food desert, low-income households do not use the opportunity to improve the quality of their diet. And when poorer families move to more food-rich neighborhoods, they continue to predominantly favor low-quality food options. It is income, not access, that explains purchasing choices. What’s also interesting, though somewhat tangential to the broader point, is that the authors find that “after excluding fresh produce, healthy foods are actually about eight percent less expensive than unhealthy foods.” I know this flies in the face of conventional wisdom, but here’s more evidence if you don’t believe me.

This is not the only study to come to this conclusion, though. For example, a 2013 CDC study comes to a similar determination, finding “no strong evidence that food outlets near homes are associated with dietary intake or BMI.” The authors hypothesize that “[a] likely reason for the null finding is that shopping patterns are weakly related, if at all, to neighborhoods in the United States because of access to motorized transportation.” Boone-Heinonen, Gordon-Larsen, and Kiefe’s 2011 study offers further support, concluding that “Fast food consumption was related to fast food availability among low-income respondents” and “Greater supermarket availability was generally unrelated to diet quality and fruit and vegetable intake.” The authors also point out that “evidence that food resources influence diet or obesity is mixed and almost exclusively cross-sectional.” This is a big problem because it means that most studies only compare food deserts to areas with sufficient access to nutritious food, but they fail to look within food deserts. So, while these studies can show that those living in food deserts consume less healthy food, they are unable to identify why.

Honestly, this is not so surprising. After all, most fast food joints have salads and grilled chicken entrees that are relatively healthy, so an individual could eat well if he or she wanted. Or, as Alex Tabarrok puts it, “Walk into a fast food joint in a food desert and ask yourself, do the customers really want brussel sprouts but are reluctantly settling for Chips Ahoy? The idea is ridiculous and not a bit insulting in denying agency to the people who live in low-income areas. If what people living in food deserts wanted was brussel sprouts, they would get them.”

Culture, not grocery store access, is much better at explaining variation in food choice. Poorer people in food deserts simply prefer less healthy food than wealthier people. I’m not sure why this is the case, but I imagine that a lack of education and poor access to government services, among other things, plays a non-trivial role. In other words, the environment in which people live still has an effect on their dietary choices, but the relationship is not as simple as the food desert narrative suggests. Put simply, it isn’t enough to expand access to healthy food. Governments and community organizations need to do more to educate people and shift their views on the value of purchasing and consuming high-quality food. Once they start demanding nutritious food, the grocers will come.