Introduction

Obesity is a major public health concern in the United States, disproportionately affecting low-income and minority families and producing long-term chronic disease consequences.¹ Diet quality is an important component of weight regulation and positive health.^2,3 High rates of obesity among low-income individuals are likely due, in part, to lower diet quality observed in this vulnerable population,⁴ which may reflect the limited access and exposure to fruits and vegetables (F&Vs) observed in urban settings in developed countries throughout the world.⁵ Indeed, poor eating patterns among low-income and inner-city populations are strongly associated with lack of exposure to F&V and high allostatic loads, which together may drive a preference for high-satiety processed foods and sugar-sweetened beverages. Urban farmers’ markets, when developed in low-income and minority neighborhoods, are one avenue to improve access and exposure to F&V⁶ and potentially reduce the risk of obesity in this population.

Several matched and bonus monetary incentive programs for food assistance recipients in the United States have been implemented to encourage the purchase of fresh F&V at farmers’ markets in under-served communities.^7-9 Coupled with expanded acceptance of electronic benefit transfer (EBT) cards at markets, incentive programs in cities such as New York, Philadelphia, and San Diego have proven effective at increasing the amount of food assistance dollars spent at farmers’ markets, as well as improving self-reported fresh F&V consumption among participants.^8,9

While these programs may successfully improve access to F&V among target populations adjacent to farmers’ markets,¹⁰ they do not directly address issues of exposure to and acceptance of F&Vs. Recent studies of farmers’ market use among recipients of the US Federal Supplemental Nutrition Assistance Program (SNAP) indicate that barriers to exposure – which includes availability in the home, cooking, serving, and tasting of F&V – may be as significant as access barriers in limiting F&V consumption and increasing intake of nutrient-poor, calorie-dense foods.^11,12 That is, parents may decline to purchase F&V because they cannot expend their limited budget on foods that will go to waste.¹⁰

Exposure interventions are defined here as activities which encourage tasting and acceptance of F&V, and include F&V tastings, cooking demonstrations, peer F&V eating environments, and family nutritional education. Access/incentive interventions include placement of markets in underserved neighborhoods and provision of financial subsidies, and directly improve the ability of families to obtain F&V. Therefore, access interventions are complemented by exposure interventions, which encourage consumption of increased F&V quantities and diversity after access is obtained. Furthermore, there is substantial evidence that conducting exposure interventions that enable children to taste F&V in novel environments may improve child acceptance, and therefore, increased consumption of F&V.¹³

Farm Fresh Rhode Island (FFRI), a non-governmental organization with the mission of providing access to local food in Rhode Island, has begun implementing a program that seeks to addresses not only F&V access, but also exposure and acceptance among federal food assistance recipients. Healthy Foods, Healthy Families (HFHF) is implemented in six farmers’ markets in low-income, urban neighborhoods from July through October each year. Families with at least one child under the age of 12, and who participate in at least one of the US food assistance programs Women, Infants and Children (WIC) or SNAP, may enroll to receive financial incentives to purchase F&V in exchange for participating in family-based nutrition exposure and education interventions held weekly at farmers’ markets.

This study was conceived as a feasibility and efficacy analysis using existing process evaluation data collected by the HFHF program during the summer of 2013. Our specific research aims included the following: (1) analyze and disseminate programmatic data on financial benefits and exposure activities; (2) examine effects of HFHF participation on participants’ F&V and soda consumption; (3) investigate the program’s effect on WIC/SNAP budget F&V expenditure patterns and use of food assistance at participating farmers’ markets; and (4) explore the relative importance of financial (access) incentives and exposure interventions as drivers of participant enrollment and retention, as well as participants’ perceptions of barriers, support, and benefits from HFHF participation.

Materials and Methods

Results

Discussion

The retention and attendance results illustrate high participant engagement in the program, despite modest financial incentives. The significant increases in vegetable consumption found in this study agree with and expand upon previous findings.⁸ Non-significant increases in fruit consumption may be partially explained by the high reported consumption of fruit at entrance to the program, as well as the fact that vegetables dominate farmers’ markets offerings. The small, but statistically significant decrease in soda consumption occurred despite none of the programmatic education efforts being targeted specifically at lowering sugar-sweetened beverage intake. It was not feasible to conduct more reliable measures of dietary intake, such as 24-hour recalls for food frequency questionnaires (FFQs) with participants, however, this preliminary finding of a decrease in soda consumption should be explored further in future studies. Previous studies examining increased F&V consumption have found mixed evidence of commensurate decreases in sugar-sweetened beverages.¹⁶ We could not find any prior research where soda intake decreased when only F&V intake was targeted.

Importantly, the study findings suggest that participants are using the program’s financial incentives to supplement, rather than replace, their WIC/SNAP F&V budget. Specifically, HFHF participants reported no change in the amount of their WIC/SNAP budget spent on F&V despite 70% of participants reporting that program participation had significantly increased their families’ consumption of F&V. This finding rebukes the argument made by some critics that F&V subsidies provided by programs such as HFHF allow participants to spend a larger percentage of their WIC/SNAP budget on less healthy items. Instead, it appears that the financial incentives offered by the HFHF program, like other monetary incentive programs at farmers’ markets, are being used effectively by participants to increase F&V consumption. The survey data also support the relative importance of HFHF’s exposure and educational components in motivating participants to both enroll and continue to attend the markets. The increase in SNAP expenditures with Bonus Bucks implementation is in keeping with findings at other farmers’ markets implementing similar financial incentives for SNAP users.

A third of participants cited the fact that their families were eating more F&V as a result of the program as the most important driver of their attendance at markets, followed by financial incentives and exposure interventions. Review of staff records regarding activities offered at each market indicated high participant attendance of children’s activities and collection of educational materials by parents, reinforcing the evidence that participants highly valued the education and exposure interventions offered by HFHF. The lack of statistically significant associations between dietary change, attendance, and monetary incentives is likely due to the small sample size of exit surveys and minimal between person variation in dietary change.

Limitations

A major limitation of this evaluation is the lack of a control group, which was not deemed feasible since waitlisted participants did not participate in surveys in adequate numbers. These findings may not be generalizable to the broader SNAP and WIC recipient population because of demographic, geographic and community factors that may specifically encourage farmers’ market attendance. Also, dietary intake was reported in “times per day” instead of “servings per day,” limiting comparison with several traditional reference studies.

Although the exit sample was statistically representative of the entire participant group, the approach of capturing participants at all markets on specific days required by staffing constraints allows the chance of some small amount of selection bias. The high self-reported consumption levels of F&V prior to program participation may have diminished dietary intake changes resulting from program participation. Participants also may have overestimated F&V intake and underestimated soda intake, in part, because of social approval bias.¹⁷ However, while research indicates that self-reporting may not accurately capture consumption, it is valid for ranking intake between participants and in paired samples via non-parametric methods.^18,19

Conclusion

Urban farmers’ market-based interventions combining exposure activities and small financial incentives can improve diet quality of low-income families. This study reinforces the existing evidence that even relatively small amounts of financial incentives that directly target F&V purchasing can be effective in helping low-income families to increase F&V intake. Importantly, however, HFHF also employed exposure and education interventions in addition to financial incentives, with participants reporting high engagement and use of the program to supplement existing WIC/SNAP F&V purchasing, instead of replacing it.

The potential of expanding the use of farmers’ markets as an intervention setting bears further examination. The social and cultural norms and values asserted in such an environment may play a reinforcing role that increases the efficacy of incentive programs and exposure interventions, warranting further research. Additional research into the tangible health effects of increased F&V consumption resulting from access and exposure improvements for target populations is warranted.

Ethical approval

The study protocol was reviewed and exempted by the Harvard T.H. Chan Institutional Review Board.

Competing interests

None to be declared.

Acknowledgements

The 2013 HFHF Program itself was made possible with generous support from Blue Cross Blue Shield of Rhode Island, the van Beuren Charitable Foundation, the Fresh Sound Foundation, Seven Stars Bakery and CVS Caremark. The authors would like to recognize FFRI’s tireless staff members, the participating farmers, and families, without whom the study could not have been conducted.

References

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