The PILI 'Āina Project - SUMMARY Native Hawaiians have the highest prevalence of cardiometabolic diseases of any population in Hawai‘i. Diet is strongly implicated as a cause of these disparities. Native Hawaiians historically consumed a diet rich in fish, fresh fruits, and vegetables, but Westernization led to profound shifts in food systems. The Hawaiian Homes Commission Act established a land base for Native Hawaiians to engage in subsistence living and practice their culture. However, today only 20% of Native Hawaiian homesteaders consume at least 1 serving of vegetables per day compared with 73% of other Native Hawaiians. Homesteaders also have twice the prevalence of diet- related diseases (obesity, diabetes, hypertension, dyslipidemia) than other Native Hawaiians. We have developed a multilevel intervention to promote healthy eating, weight loss, and cardiovascular health for overweight/obese Native Hawaiian adults entitled “PILI ‘Āina.” At the individual-level PILI ‘Āina provides 3 months of culturally tailored education based on the Diabetes Prevention Program’s Lifestyle Intervention. The education aims to improve self-management of prevalent cardiometabolic disease (type 2 diabetes, hypertension, and dyslipidemia) and to reduce risk factors for developing new diet-related illness. PILI ‘Āina also includes a 6- month household-level component that provides home garden materials and training as a means of connecting with traditional NH culture, values, and lifestyle in the home environment. A pilot study of PILI ‘Āina was well- received by participants, with 100% retention over 9 months and promising results for cardiometabolic outcomes. We will now conduct a group-randomized controlled trial of PILI ‘Āina on 7 O‘ahu homesteads. First, we will interview the past PILI ‘Āina pilot participants to refine the intervention to better support year-round home gardening and a traditional Native Hawaiian diet. Second, we will conduct a group-randomized controlled trial to test the efficacy of PILI ‘Āina compared to a control group among 180 adult homesteaders with overweight/obesity who have at least 1 other cardiometabolic disease. Data collection will occur at baseline and 3, 9, and 12 months. Primary outcomes are diet quality, adiposity, hemoglobin A1c, blood pressure, and lipids. Secondary outcomes are behavioral and psychosocial factors (e.g., physical activity, self-efficacy) that might mediate effects on primary outcomes. Third, a community-level program will feature traditional cooking and tasting events on all 7 homesteads. Our Specific Aims are to 1) Refine the PILI ‘Āina intervention to optimize its effectiveness for improving diet and managing diet-related cardiometabolic diseases on Native Hawaiian homesteads; 2) Test the efficacy of PILI ‘Āina compared to a control group for improving diet, biomarkers, and behavioral and psychosocial risk factors among homesteaders with diet-related cardiometabolic diseases; and 3) Evaluate the ability of community-wide food demonstrations to promote traditional diets and improve social cohesion on Native Hawaiian homesteads. Results will address the American Heart Association’s call for evidence-based programs to improve diet at the household level for preventing cardiovascular disease.