PROJECT SUMMARY/ABSTRACT The overarching objective of this trial is to test the impact of a full-service mobile food market (“a grocery store on wheels”) on diet quality, food insecurity (i.e., uncertain or not enough access to food for a healthy life) and food purchases in underserved communities. We will also explore personal, social, behavioral, and environmental factors that may influence adoption of mobile market shopping. The long-term goal of our work is to increase equity in diet/weight-related health outcomes by improving access to and intake of healthy foods. Currently, individuals from racial/ethnic minority backgrounds and those who experience low incomes are disproportionately impacted by poor nutrition and diet/weight-related health outcomes such as type 2 diabetes and high blood pressure. Lack of affordable, healthy food access and food insecurity are believed to be important contributing factors to these disparities. Mobile food markets have been proposed as a strategy for mitigating these health disparities because they bring low-cost, healthy food directly to underserved populations. Mobile food markets are increasingly available nationally and have been supported by state legislation, but little is known about their effectiveness. Full-service mobile markets may improve multiple aspects of the diet by providing foods to meet all dietary needs through a convenient one-stop shop. The full- service mobile market to be tested in this proposal (Twin Cities Mobile Market) sells staple foods from a bus that regularly visits low-income neighborhoods. Foods are sold at prices 10% below those of grocery stores. SNAP/EBT is accepted, and a state-funded fruit/vegetable incentive program (Market Bucks) is available to shoppers. Working in partnership with our community team members, we will enroll 6 community sites (clusters) in two waves (12 total sites/clusters) and recruit 20 participants per site (N=240). We will collect baseline data and randomize sites to either receive the full-service mobile market intervention or serve as the waitlist control. We will then implement the full-service mobile market at intervention sites, follow participants for one year, and collect follow-up data. After follow-up data collection, waitlist control sites will receive the full- service mobile market intervention. For Aim 1, changes in diet quality (our primary outcome measured with the Health Eating Index-2015) and food insecurity (measured with the 18-item U.S. Adult Food Security Survey Module) will be assessed. For Aim 2, changes in food purchases will be objectively measured by collecting one month of food purchase receipts at baseline and follow-up data collection. We will also assess mobile market food purchases during the implementation period with customer loyalty cards. For Aim 3, we will explore the factors that influence adoption of mobile market shopping. Findings will provide evidence on the effectiveness of a full-service mobile market to...