Understanding Food Deserts

By Anise Vance

January 26, 2016

At the close of the 20th century, researchers and scholars, increasingly interested in issues of public health, introduced a new term into our collective social discourse: food desert. Defined as an area with little or no access to quality and healthy food (at, critically, affordable prices), food deserts were easily identifiable in almost every American urban center and rural region. During the 21st century, as public health took on increased importance in policymaking, research on food deserts multiplied. While progress has been made in both awareness of and policymaking directed at nutritional access, a recent study, conducted by Jerry Shannon, demonstrates what little we understand about food deserts.

Shannon, a professor of geography at Georgia State University, noticed a commonality among research on the availability of quality food: studies were primarily concerned with assessing the density of available supermarkets and the distance between residences and the closest food source. While logical, and a necessary starting point, density and distance are not, in reality, an accurate predictor of health outcomes. Studies of California schoolchildren, low-income Philadelphia neighborhoods, and policy interventions in Flint (MI), revealed that decreasing the distance between residences, and increasing the density of available supermarkets, do not, on their own, alter dietary behavior.

Looking at the results of that recent scholarly work, Shannon then asked, what factors — in addition to density and distance — are at play?

To address his question, Shannon identified two low-income areas in Minneapolis, one of which included sub-populations with low-access to food sources. Shannon recruited 38 neighborhood residents to participate in a five day study. The participants’ daily movement and food sources were tracked during the five-day period. Additionally, participants were interviewed twice, once before and once after the study, to gain further insight into their daily patterns. The results reveal a reality more intricate than simple distance-based analyses suggest:

"Although both areas contain a range of stores including at least one large supermarket, study participants used food sources a median of 2.8 km from their homes."

Further highlighting that finding, Shannon notes that when making trips to large supermarkets, the median distance travelled was 5 km, despite the 2 km average distance between participants and the closest large supermarket. Participants shortest trips were to convenience stores and mid-sized grocers. Those trips were, however, complemented by farther travel to larger stores. Notably, particular ethnic groups, in search of foods not available in standard supermarkets, traveled well beyond the closest grocery to find the products they desired. While income, gender, and education were factors in distance travelled, a similar trend held across demographic categories: residents often travelled farther than was strictly necessary to buy their food.

Shannon found that of the 217 trips participants made to 158 food sources, only 28 locations were visited more than once. Interviews revealed that everyday mobility — that is, one’s daily movement across and within neighborhoods — was a significant factor in where people bought food. While car ownership, public transportation, and social networks all played a role in participants’ mobility, the neighborhood supermarket was far from their single or assumed choice regardless of transportation options. Participants undoubtedly preferred using several stores to meet their needs. Shannon’s research thus

"...emphasizes the multiple ways in which food access is tied to everyday mobility, which problematizes a conceptualization of food deserts as static, clearly bounded space."

In more direct terms: neighborhoods will influence but not determine where and how people buy food. Participants identified numerous other factors in their food purchasing decisions. Perceived quality of food, perceived safety of a supermarket’s location, attitude of a store’s staff, available transportation to a food source, and diversity of food offerings were among the many variables that went into seemingly simple purchasing decisions.

The view of food access that Shannon presents is far more nuanced and complex than that of standard analyses. Understanding local context — transportation options, housing location, perceptions of quality and neighborhood safety, affordability — that drives purchasing patterns is key to planning for healthier and more affordable food options. Importantly, Shannon’s work points to a potential and dramatic shift in our policy-related thinking on food access: planting large supermarkets in low-income areas is likely less effective than nurturing a diverse array of smaller grocers located both within low-income neighborhoods and throughout cities.