FOOD DESERTS Lori Kowaleski-Jones

Department of Family and Consumer Studies

University of Utah

Energy Balance Research Group

Food Desert

Broadly conceptualized as limited access to affordable and nutritious foods, particularly in low income areas

Food Environment and Health

Overweight increasing in the United States Recent research has linked food

environments to health 2008 Farm Bill called for information about

the identification of food deserts But how to define…

USDA Food Desert Definition defines a food desert as a low-income census tract

where a substantial number or share of residents has low access to a supermarket or large grocery store:

To qualify as a “low-income community,” a census tract must have either: 1) a poverty rate of at least 20% OR 2) a median family income at or below 80 % of the area's

median family income; To qualify as a “low-access community,”

at least 500 people and/or at least 33 % of the census tract's population must reside more than one mile from a supermarket or large grocery store (for rural census tracts, the distance is more than 10 miles).

Food Deserts in Salt Lake City Utah (USDA)

Alternate definitions

Does it have to be low income areas? Are deserts mirages? Estimates suggest

that only 15% of people shopped for food within their own census area.

Should the focus be on supermarket? (what about smaller retailers and farmers

markets?)

Research on Food Deserts in SLC

Coauthors are Jessie Fan, Ikuho Yamada, Barbara Brown, Ken Smith and Cathleen Zick.

Different data sets have been used—do they have comparable information?

Variety of geographic scales to describe local food environment and the methods used to describe distance

Our study was an initial assessment of how sensitive the analyses are to these issues

Our Study

Assess the comparability of data from Reference USA Dun and Bradstreet

Roughly, about a 1/3 of the records in each data set are unique

Research results can only be as good as the data used

• 564 census block groups

Research Aims

1. Where? Explore variation with different data sets to measure food deserts and their prevalence in Salt Lake County Compare “all grocery stores” (GS) to “large

grocery stores” (LGS) Simple in-out measure vs. 1-km radius buffer

measure2. Who? Use multivariate analysis to relate

demographic characteristics and built environment factors to the likelihood that a census block group will be a food desert.

3. Low income only? Incorporate an economic component to the definition of food deserts

All Grocery Store (GS) and Large Grocery Store (LGS) Counts in Salt Lake County: by Data Source & Sales Volume

DB RefUSA

All grocery 243 246

Large Grocery (sales volume>$1M)

70 95

Research Aim 1: Where?

Alternative Definitions of Food Deserts

Dichotomous measure, 1= BG (Block Group from census) contains any grocery store

Dichotomous buffer measure captures whether a BG is covered by any 1km buffer of grocery stores

1km buffer continuous measure: percentage of the BG land area that is not covered by the 1km grocery store buffer These three measures are repeated for large grocery

stores (sales volume > = million) These measures are repeated for whether the above is in

a low income (median household income < 25th percentile for the county) or higher income BG

Census Block Group

R=1km

Food Outlet A

R=1km

Food Outlet B

R=1km

Food Outlet C

Definition of Food DesertBG Income

DB RefUSA

No GS in BG

All $ 73% 76%

Low $ 67% 65%

BG > 1km from any GS

All $ 8% 8%

Low $ 3% 3%

% of BG area > 1km from any GS

All $ 36.1% 37.3%

Low $ 22.8% 21.5%

No Large GS in BG

All $ 88% 83%

Low $ 88% 81%

BG > 1km from any Large GS

All $ 22% 15%

Low $ 18% 17%

% BG > 1km from any Large GS

All $ 58.6% 49.7%

Low $ 50.1% 42.6%

dichotomous with all grocery stores dichotomous with large grocery stores only

Buffer-based dichotomous with all grocery stores Buffer-based dichotomous with large grocery stores only

Results Aim #1

Using the most basic definition, 73% of Salt Lake County BG is a food desert; higher when only large grocery stores are considered

Using the 1 km circular buffer definition, much smaller estimate of food deserts; variation across data sets; variation even more distinct when large grocery stores are considered

Aim 2: Who?

Demographic Characteristics and Built Environment

Ave. residents per sq. mile (density, BG) Ave. intersections w/in ¼ mile of residence

(design, BG) Ave of (1999 – Median Yr. Built) (design,

CT) Within the Block Group, the proportions of

African Americans Hawaii and Pacific Islanders Asians Hispanics

No GS No LGS

DB RefUSA DB RefUSA

% African American .98 1.21 .94 .97

% Pacific Islander .84 .71 .80 .78

% Hispanic .96 .95 1.01 .78

% Asian .94 .94 .96 .91

Population density 1.04 1.1 1.01 .99

Age of housing .95 .74 .94 .87

Intersection density .85 .95 .99 .95

Median family income 1.03 1.02 1.01 1.00

Odds ratios for BG not covered by 1 km circular buffer of any grocery store (GS) and not covered by large grocery store (LGS)

Results Aim #2

Little variation across data sets Little variation across size of grocery store Overall, BG that have older housing stock,

greater intersection and population density have lower odds of being food deserts

BG with higher median family income are more likely to be food deserts

Aim #3: Low income only? Separate Analyses for lower income and higher income CBGs

Results Aim #3

Overall, similar associations between demographic characteristics and odds of non coverage across income level of BG—exceptions In lower income BGs, higher proportion of

Hispanics predicts lower odds for FD, whereas in higher income BGs, higher proportion of Hispanics predicts higher odds for FD

In lower income BGs, higher median income predicts lower odds for FD, whereas in higher income BGs, higher median income predicts higher odds for FD

Discussion• Aim #1: variation across data sets in identification of food deserts

Future research and policy activity should be careful to appreciate the limitations of data used to define and identify food deserts.

Recommendation: If the focus is to identify FD for policy implementation, more detailed measurements and multiple data sets give a more comprehensive picture.

Aim #2: limited variation across data sets in estimating correlates of food deserts

Surprising, given the lack of agreement across data sets Recommendation: If the focus is to estimate correlates of food

deserts, employing a single data source seems to be fine. Aim #3: some variation in direction of odds ratios across income

specification Preliminary and likely proxying for more complicated processes Recommendation: future research incorporate economic

dimensions in food desert research.

Implications

Controversy that there has been a dearth of evidence linking food deserts to dietary health. Consensus that improving access might not change consumer behavior. Patterns might persist, role of preferences and prices.

Food Deserts and Public Policy

Recent activity has been the Healthy Food Financing Initiative 2010 with the aim of eliminating food deserts

More information on spatial elements of food environment http://www.ers.usda.gov/Food

Atlas/

http://www.ers.usda.gov/data/fooddesert/