Our Research

Vouchers 4 Veggies – EatSF, in partnership with the UCSF Center for Vulnerable Population’s Food Policy, Health, and Hunger research program, conducts research and evaluation measuring the impact of produce prescription and healthy food voucher programs on food security and dietary intake among low-income populations. Through our research we seek to advance nutrition policies that equitably increase healthy food access and improve health. This page highlights our research findings, publications from our founder, Dr. Hilary Seligman, and relevant resources from the field.

UCSF Center for Vulnerable Populations

Our Findings:

Fruit and Vegetable Vouchers in Pregnancy: Preliminary Impact on Diet & Food Security


Study Summary:

Pregnancy is a critical time period for supporting food security and maternal nutrition because of long-term potential impacts on the developing fetus. We conducted a pre-/post-analysis of pregnant WIC participants (n = 592) in San Francisco receiving $40/month of fruit and vegetable vouchers in addition to the standard WIC package. We compared pre-/post- changes to a comparison group of non-pregnant WIC participants (n = 108) receiving only the standard WIC package. We observed significant improvements in food security and mean daily frequency of total vegetables, combined fruits and vegetables, salad and non-fried potatoes (p < .05 for all comparisons).

Ronit A. Ridberg , Sanjana Marpadga , Melissa M. Akers , Janice F. Bell & Hilary K. Seligman (2020): Fruit and Vegetable Vouchers in Pregnancy: Preliminary Impact on Diet & Food Security, Journal of Hunger & Environmental Nutrition, DOI:10.1080/19320248.2020.1778593

Effects of Alternative Food Voucher Delivery Strategies on Nutrition Among Low-Income Adults


Study Summary:

Nutrition assistance programs are the subject of ongoing policy debates. Two proposals remain uninformed by existing evidence: whether restricting benefits to allow only fruit and vegetable purchases improves overall dietary intake, and whether more frequent distribution of benefits (weekly versus monthly) induces more fruit and vegetable consumption and less purchasing of calorie-dense foods. In a community-based trial, we randomly assigned participants to receive food vouchers that differed in what foods could be purchased (fruit and vegetables only or any foods) and in distribution schedule (in weekly or monthly installments, holding total monthly value constant). The use of vouchers for fruit and vegetables only did not yield significantly greater improvements than the unrestricted voucher did in terms of fruit and vegetable consumption or Healthy Eating Index (HEI) score. Weekly vouchers also failed to yield significantly greater improvements than monthly vouchers did. Proposed policies to make assistance more restricted or more frequent, while holding benefit value constant, might not improve nutrition among low-income Americans.

Sanjay Basu, Christopher D. Gardner, Justin S. White, Joseph Rigdon, Mandy M. Carroll, Melissa Akers, & Hilary K. Seligman (2019): Effects of Alternative Food Voucher Delivery Strategies on Nutrition Among Low-Income Adults, Health Affairs, DOI: 10.1377/hlthaff.2018.05405

Heterogeneity in the Effects of Food Vouchers on Nutrition Among Low-Income Adults: A Quantile Regression Analysis


Study Summary:

Purpose: To determine whether baseline fruit and vegetable (FV) intake or other predictors are associated with response to food vouchers (change in FV intake) among low-income adults.
Design: Secondary analysis of a randomized, 2 x 2-factorial, community-based trial.
Setting: San Francisco, California.
Intervention: Participants were mailed $20 of food vouchers monthly for 6 months, and randomized to 1 of 4 arms according to: eligible foods (FV only or any foods) and redemption schedule (weekly or monthly).
Results: FV-only weekly vouchers were associated with increased FV intake at the 25th percentile (0.24 cups/day, p ¼ 0.048) and 50th percentile (0.37 cups/day, p ¼ 0.02) of the distribution, but not at lower and higher quantiles. Response to the vouchers diminished 0.10 cups/day for each additional household member (p ¼ 0.02).
Conclusion: Response to food vouchers varied along the FV intake distribution, pointing to some more responsive groups and others potentially needing additional support to increase FV intake. Larger households likely need vouchers of higher dollar value to result in similar changes in dietary intake as that observed in smaller households.

White JS, Vasconcelos G, Harding M, et al. Heterogeneity in the Effects of Food Vouchers on Nutrition Among Low-Income Adults: A Quantile Regression Analysis. American Journal of Health Promotion. September 2020. doi:10.1177/0890117120952991

Relevant Selected Articles from Dr. Hilary Seligman, MD, MAS:

Dr. Hilary Seligman is one of the nation’s foremost experts on the health implications of food insecurity. Dr. Seligman is Core Faculty for UCSF’s Center for Vulnerable Populations at San Francisco General Hospital and Professor of Medicine and of Epidemiology and Biostatistics. She is also the Director of the CDC’s Nutrition and Obesity Policy Research and Evaluation Network, Senior Medical Advisor for Feeding America, and the Director of the Food Policy, Health, & Hunger Program at UCSF.

For more information about Dr. Hilary Seligman, click here.
Please hover and click on the key selected articles from Dr. Hilary Seligman to read more.

Food Insecurity & Chronic Disease

Food Insecurity & Health Care Expenditures

Supplemental Nutrition Assistance Program (SNAP) & Nutrition Incentive Programs

The following resources and publications highlight and support relevant work around produce prescription (Rx) and nutrition incentive programs. Please hover and click on each resource to read more.


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