Community Investments and Diet-related Outcomes: A longitudinal study of residents of two urban neighborhoods

"Diet is a social determinant of health. Low income, racial minorities are at increased risk for mental illness, chronic disease, higher mortality, and lower life expectancy. Also, they often have limited access to healthy foods. Evidence suggests that the neighborhood food environment may influence diet and obesity. To promote healthy eating for improved health, the federal government financed the Healthy Food Financing Initiative to incentivize supermarkets to open in neighborhoods lacking access to fresh food (i.e. food deserts).

Funded by NCI, the RAND PHRESH study was designed as the largest natural experiment (n=1,372) to assess if opening a supermarket in a food desert actually impacts healthy eating. We leveraged a longitudinal pre-post design using an "intervention" neighborhood and using qualitative informative with quantitative methods to identify a "counterfactual". A community-based participatory research (CBPR) approach to ensure study success including enrollment and retention. We conducted a rigorous evaluation using difference-in-difference and Instrumental variables methods with the rich data to estimate the "intervention effect" on residents' diet. While we found short-term positive effects, they disappeared in the long term. On the other hand, there were large, sustained effects on secondary outcomes such as perceptions and neighborhood satisfaction. Diet, like all health behaviors, is hard to change. A combination of individual and neighborhood level interventions may be necessary to bring about sustained dietary changes."