Date of Award

January 2012

Document Type

Open Access Thesis

Degree Name

Master of Public Health (MPH)


School of Public Health

First Advisor

Kelly Brownell

Second Advisor

Kathryn E. Henderson


Federal food assistance and nutrition programs share a mission of helping low-income households achieve adequate nutrition, but the benefit structures of the programs differ significantly. The Women, Infants and Children program (WIC) offers vouchers for a limited number of nutritious foods, while the Supplemental Nutrition and Assistance Program (SNAP) has few restrictions on benefit use. The objectives of this research were to compare the composition of grocery purchases among WIC and SNAP households and assess the effect of benefit design on total grocery purchases. To accomplish these objectives, transaction data from a supermarket chain was used to assess store purchases (n=7,358,835) of 22,464 low-income households in January-June 2011. Purchased products were classified into fourteen categories and thirty subcategories. The proportion of grocery spending was compared for four groups of low-income households: Former WIC, WIC, SNAP and WIC & SNAP. General linear regression models controlling for program participation and store level socio-demographics were used to predict purchase behavior by food category. Participation in nutrition assistance programs is associated with purchasing behavior. WIC households spent a larger proportion of grocery dollars within WIC targeted categories and a smaller percentage of grocery dollars within discretionary food categories (e.g., snack foods, desserts), compared to the other three groups. The percent of purchases within WIC-targeted food categories exceeded the share of WIC spending in total groceries, indicating a spillover effect of WIC-category purchases into personal funds. Conversely, SNAP households spent a greater proportion of grocery dollars within discretionary food categories, crowding out spending on fruits, vegetables and dairy, compared to the other groups. These results suggest the benefit design of WIC appears to influence purchasing decisions, including those made with personal funds. Limiting SNAP purchases could shift spending towards recommended foods, and likely improve the diets of participating households.


This is an Open Access Thesis.