In this project we examine the definition of “food deserts” created by the US Department of Agriculture, and present some data on food deserts in the Bay Area.
Broadly, food deserts are regions with low access to healthy and affordable foods. Food deserts can be found in rural areas where grocery stores may be difficult to access, but can also occur in urban communities like the counties in the Bay Area. Here we will look at census tracts and determine if they are food deserts. Census tracts are regions within a country that are grouped together by the US Census.
The US Department of Agriculture (USDA) bases its definition of food deserts on the following indicators of access [1]:
Accessibility to sources of healthy food, as measured by distance to a store or by the number of stores in an area.
Individual-level resources that may affect accessibility, such as family income or vehicle availability.
Neighborhood-level indicators of resources, such as the average income of the neighborhood and the availability of public transportation.
A census tract is designated as a food desert based on it being identified as a “Low Income (LI)” or “Low Access (LA)” area. A census tract is a low income area if it satisfies any of the following [1]:
The tract’s poverty rate is 20 percent or greater;
The tract’s median family income is less than or equal to 80 percent of the State-wide median family income;
The tract is in a metropolitan area and has a median family income less than or equal to 80 percent of the metropolitan area's median family income.
Low access census tracts are those who have a large number of people living far from a supermarket or large grocery store. The USDA has the following three descriptions of a food desert [1]:
Half-mile Food Desert. Low-income census tracts where a significant number (at least 500 people) or share (at least 33 percent) of the population is greater than ½ mile from the nearest supermarket or large grocery store for an urban area or greater than 10 miles for a rural area.
1-mile Food Desert. Low-income census tracts where a significant number (at least 500 people) or share (at least 33 percent) of the population is greater than 1.0 mile from the nearest supermarket, supercenter, or large grocery store for an urban area or greater than 10 miles for a rural area.
1 and 20 mile Food Desert. Low-income census tracts where a significant number (at least 500 people) or share (at least 33 percent) of the population is greater than 1.0 mile from the nearest supermarket, supercenter, or large grocery store for an urban area or greater than 20 miles for a rural area.
We give a name to each type of food desert above in order to reference these below. Our emphasis on the distance threshold for urban areas is due to the fact that we are focusing on the Bay Area which is predominantly urban.
After understanding the definitions of a food desert used by the USDA, we began to examine the food deserts in the Bay Area. To the right is a map showing the low income communities in the Bay Area. We can see a high concentration of these in the East Bay -- Richmond, Oakland, San Leandro, Hayward.
Of these low income areas, we can see the half mile food deserts and 1 mile food deserts highlighted below.
Using open access data from the USDA, we were able to look closer at the communities which are classified as food deserts.
Using Python to analyze the data provided by the USDA, we are able to see the number of food deserts in each bay Area County. Below one can see the number of half mile and 1 mile food desetrs in each county. We note that Alameda county and Contra Costa County have the highest number of 1 mile and half mile food deserts, respectively. We can also see that Marin County and Napa county have the lowest number of both types of food deserts.
When we focus on Alameda Country specifically, we find that 6 census tracts are classified as 1 mile food deserts. According to the 2010 Census, these tracts are home to 26,038 people.
When we expand the definition of a food desert to that of the half-mile food desert, we see 83 census tracts listed as food deserts. These tracts are home to 364,729 people.
We present below the demographic breakdown of the people living within half mile and 1 mile food deserts in both the Bay Area and in Alameda County specifically. These charts were created by calculating the average number of people from each demographic group that ives in a census tract labeled as a food desert.
Here we examine what characteristics are shared by census tracts labeled as food deserts of any type. Each census tract in the Bay Area is given an ID number from 1 to 359. If the census tract is either a half mile or 1 mile food desert, the census tract is assigned a blue dot. Otherwise the census tract is assigneed an orange dot. The plots below show how these census tracts compare in terms of the following:
poverty rates,
median family income,
number of housing units with SNAP benefits, and
number of households without a vehicle (which affects access).
From these plots we can observe that food deserts have higher poverty rates, lower family income, and higher frequency of SNAP households. The plots on households without a vehicle show a less well defined difference between food deserts and non-food deserts.
Data on the number of food deserts in the Bay Area is available for 2013 and 2017. Below we present charts which give some idea of how food deserts have changed within some Bay Area counties.
Mandela partners focuses on "building systems change through our cross-cutting areas of work that creates long-term health and economic opportunity in partnership with under-resourced communities" [2]. Mandela partners has community produce stands at the locations to the right.
"Since its early roots in West Oakland, Mandela Partners has been leading innovative and community-centered initiatives to address two competing food access challenges: ensuring fair pricing for small farmers who grow sustainably while simultaneously keeping the cost of produce affordable enough for low-income residents.
With the proliferation of diet-related disease, communities across the Bay Area are seeking means to transform the health landscape and create food secure neighborhoods. Our food access programs were created to secure residents’ right to access fresh, affordable, and healthy food." [2]
[1] US Department of Agriculture; Economic Research Service; Food Access Research Atlas. https://www.ers.usda.gov/data-products/food-access-research-atlas/documentation/
[2] Mandelas Food Partners (2021). https://www.mandelapartners.org