The term “food desert” describes neighborhoods and communities that have limited access to affordable and nutritious foods. In the United States, those who live in urban and rural low-income neighborhoods are less likely to have access to supermarkets or grocery stores that provide healthy food choices. While many food desert studies have focused primarily on their socioeconomic determinants, less is known about their public health impacts—including the prevalence of obesity and the incidence of chronic diseases—on local populations.

As part of a year-long congressionally mandated study coordinated by the Economic Research Service (ERS) of the U.S. Department of Agriculture, the Institute of Medicine (IOM) and the National Research Council (NRC) were asked to convene a two-day workshop to understand the public health effects of food deserts. On January 26-27, 2009, workshop speakers provided presentations on how to measure and understand the extent of food deserts, their impact on individual behaviors and health outcomes in various populations, and effective ways to increase the availability of fruits and vegetables and to improve the food environment. Workshop participants also identified areas where additional research could be helpful to inform future efforts to increase the availability of affordable and nutritious foods. It was beyond the workshop’s scope to examine ways to decrease access to unhealthy food options.

Although larger food stores are not the only outlets able to sell healthy food, their presence (or lack) is used as a proxy for access to healthy lower-cost food options. Using national-level data and community-level research, presenters confirmed that food deserts do exist in the United States, particularly in lower-income, inner-city and rural areas with few supermarkets and numerous smaller stores that stock very limited healthy food items such as fruits and vegetables. Mapping shows that these are also frequently areas with high rates of obesity and chronic, diet-related diseases. However, presenters emphasized that food retail is only one component of the total food environment that affects how people eat and, more fundamentally, their health. Another caveat is that the supply of healthy food will not suddenly induce people to buy and eat such food over less-healthy options, especially when relative prices of the healthier foods are high.

To better understand the public health implications of food deserts, speakers reviewed the evidence on the link between different foods and health outcomes. The research showed that the increased consumption of fruits and vegetables, whole grains, and healthy fats slows weight gain but does not reduce weight unless they are substituted for other more energy-dense foods, and it does have benefits in terms of cardiovascular disease (CVD) risk and some cancers. Consumption of sweetened beverages has doubled since 1965, and this has had a harmful effect on weight, CVD, and some cancers. Perhaps not coincidentally, the relative price of these beverages has decreased over time. The evidence linking diet to health outcomes discussed at the workshop points to the reality of the complex relationships between interventions and health outcomes, therefore there is no magic bullet for improving health and those limitations need to be kept in mind.

Research-based experiments and policy interventions to mitigate food deserts have included working with supermarket chains to determine new store sites in underserved areas, providing incentives to small-store owners to improve offerings, and encouraging the growth of farmers’ markets that can improve access to fresh produce and possibly also accommodate payment with government nutrition assistance programs from the Supplemental Nutrition Assistance Program and the Special Supplemental Nutrition Program for Women, Infants, and Children.

A number of specific research needs were identified throughout the course of the workshop. These include the need for longitudinal research to track the same population over time as changes in their food environment occur, a focus on multiple outcome measures given the complexity of the food environment, and the role of price in food choice. Solving the food desert problem might not alone improve health or necessarily change what individuals eat. However, understanding where food deserts exist in the United States can provide guidance on where changes can be made to improve the availability of affordable healthy food options. Marshaling resources to help alleviate food deserts in this context will be a step toward better health for all Americans.

This report is a summary of workshop presentations and discussions. Meeting transcripts and presentations served as the basis for the summary. The planning committee served as the organizing body for the workshop, and they identified themes for the workshop and invited speakers from the United States and the United Kingdom to address the various issues. The biographical sketches of members of the planning committee can be found in Appendix A, and the workshop agenda is found in Appendix B. Appendix C provides biographical sketches of invited speakers and moderators listed on the agenda. More than 75 stakeholders from the general public attended the workshop, and a list of those participants from the public is found in Appendix D.

The reader should be aware that the material presented here expresses the views and opinions of individuals participating in the workshop as either speakers, moderators, or audience members, and not the deliberations or conclusions of a formally constituted IOM or NRC committee. The invited speakers provided presentations based on their research or perceptions of research in the field. The purpose of the workshop was not to reach consensus on any single issue, but to gather information to inform the ERS food desert study in its report to Congress. These proceedings summarize only the statements of workshop participants and are not intended to be an exhaustive exploration of the subject matter nor a review of all empircal evidence on the topic.