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Food access: prices, the retail environment, and health

IOM Workshop: Mapping the Food System an its Effects

September, 2013 Washington, DC

Parke Wilde

Literature Review: Overview

Food spending and health: • Food insecurity hypothesis • Food environment hypothesis • Food price hypothesis

Source: Wilde, Llobrera, and Valpiani, 2012. Current Obesity Reports.

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Outline

• Prices • Food retail environment

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Outline

• Prices • Food retail environment

Theory

Fruits and Vegetables

Price

Quantity

Theory

Fruits and Vegetables

Price

Quantity

Demand

Theory

Fruits and Vegetables

Price

Quantity

Supply

Theory

Fruits and Vegetables

Price

Quantity

Demand

Supply

Source: Andreyeva et al. (2010), American Journal of Public Health.

Elasticities show how beverage quantities respond to changes in prices and total beverage spending

Source: http://www.fns.usda.gov/ora/MENU/WhatsNew.htm .

Abt Associates | pg 12

Interim Impact on Mean TFV Intake

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Cup-

Equi

vale

nts

Treatment group (N=1047 recalls over 946 respondents)

Control group (N=1033 recalls over 924 respondents)

}

impact = 0.22 cup-equivalents per day;

25% difference (p=0.001)

1.09 cup-equivalents per day

0.88 cup-equivalents per day

Effect of prices on child obesity

Source: Wendt and Todd (2011).

Literature Review: Food Prices and Mean BMI

Source Treatment BMI Design Type

FOOD PRICES

Wendt and Todd (2011)

A 10% price increase low-fat milk 0.07 ***

Longi- tudinal

A 10% price increase dark green veg 0.05 ** A 10% price increase for sweet snacks -.05 *** A 10% price increase for carbonated beverages 1 year prior1 -.08 ***

A 10% price increase for 100% juices 1 year prior1 -0.06 ***

A 10% price increase fresh/frozen starch veg 1 year prior1 -0.06 ***

Source: Wilde, Llobrera, and Valpiani, 2012. Current Obesity Reports.

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Conclusions: Prices Main point: • It is plausible that retail prices affect

health. • In a framework, perhaps better to

address what you would like to happen to supply and demand (rather than prices).

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Conclusions: Prices Research caution: • For each study, what is the source of

price variation?

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Conclusions: Prices Policy caution: • In contemplating changes to market

prices, consider their effect on incentives for both producers and consumers.

• In contemplating taxes/subsidies, realistically assess the policy-making process.

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Outline

• Prices • Food retail environment

Literature Review: Food Environments

• Larson N, Story M, Nelson M. (2009). Neighborhood environments: disparities in access to healthy foods in the U.S. Am J Prev Med.

• Giskes K, van Lenthe F, Avendano-Pabon M, Brug J. (2011). A systematic review of environmental factors and obesogenic dietary intakes among adults: Are we getting closer to understanding obesogenic environments? Obes Rev.

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Matrix of Options

Food Environment

Measures

Other Measures of

Access

Geographic Unit

Geographic Boundary

•Density •Proximity •Composite

•Vehicle •Poverty •Food Insecurity

•Political •Census •Geometric

•Buffer •Distance, travel time •Size

≥1 mile from nearest supermarket

no automobile ≥ 10 miles

<1 mile from supermarket

and has automobile

Orange shading represents poor access to a supermarket.

Low access and low income (1)

Note: Analysis at the block group level.

low access: has ≥ 500 persons or ≥ 33% of population

≥ 1 mile from supermarket

rural urban

low access: has ≥ 500

persons or ≥ 33% of pop ≥ 10 miles

from supermarket

Orange shading represents tracts with low access and low income.

low income: low relative income or poverty rate ≥ 20%

Low access and low income (2)

Note: Analysis at the census tract level.

Low-income areas are more likely to have a supermarket nearby.

Source: Ver Ploeg, Breneman, Dutko, Williams, Snyder, Dicken, and Kaufman (2012). Access to Affordable and Nutritious Food: Updated Estimates of Distance to Supermarkets Using 2010 Data, ERR-143, USDA/ERS.

-6-4

-20

2

0 .2 .4 .6 .8 1Poverty rate, people

lndist lndistFitted values

Census block groups: log(distance) from supermarket and poverty rate

Note: red indicates “low income/low access.” Source: Wilde and Llobrera (in review).

Literature Review: Food Environment and Mean BMI

Source Treatment BMI Design Type

FOOD ACCESS

Block et al. (2011)

A 1-km increase in distance to fast-food restaurant -0.11 * Longitudinal

A 1-km increase in distance to convenience store 0.02

Longitudinal

A 1-km increase in distance to grocery store -0.06 *

Longitudinal

A 1-km increase in distance to chain supermarket -0.02

Longitudinal

Source: Wilde, Llobrera, and Valpiani, 2012. Current Obesity Reports.

Literature Review: Food Environment and Odds of Obesity

Source Treatment OR Design Type

FOOD ACCESS

Currie et al. (2011)

An additional fast food restaurant within 0.1 miles (compared to having one within 0.25 miles)4

1.08 **

Longitudinal

Ludwig et al. (2011)

Receipt of a voucher to live in a low-poverty census tract versus no change in benefits4

0.95

Randomized trial

Source: Wilde, Llobrera, and Valpiani, 2012. Current Obesity Reports.

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Conclusions: Retail Environment Main point: • It is plausible that the food retail

environment affects health, although empirical evidence is mixed.

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Conclusions: Retail Environment Research caution: • Correlation is not causation. • Diagnosis of food deserts should

– avoid presuppositions, – account for vehicles, and – account for population density.

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Conclusions: Retail Environment Policy caution: • Address poverty. • Consider neighborhoods not just from

the perspective of a community-based focus group, but also from the perspective of a commercial retailer.

• In contemplating retailer subsidies, focus on areas of greatest need only.

For more information … Food Policy in the United States: An Introduction

(Routledge/Earthscan, March 2013)

www.usfoodpolicy.com