ABSTRACT The increasing prevalence of diet-related chronic conditions, such as obesity, diabetes, and cardiovascular disease, has elevated the importance of improving nutrition as a national health priority. However, critical evidence remains limited on the long-term health outcomes and economic impacts of interventions aimed at improving dietary intake and reducing food and nutrition insecurity. This project seeks to fill these critical gaps by evaluating the health and economic effects of selected food and nutrition interventions, generating evidence to inform national priorities related to reducing diet-related disease and improving population health. Guided by three criteria – (a) strategic priorities outlined in the national report on Hunger, Nutrition, and Health, (b) a conceptual framework incorporating the health impact pyramid and NIMHD research framework on the domains of influence (population- vs. individual-level), and (c) the availability of supporting empirical evidence, we will evaluate four promising and scalable interventions: (1) expanding the USDA-supported Gus Schumacher Nutrition Incentive Program and (2) reforming the Supplemental Nutrition Assistance Program (SNAP) benefit structure and eligibility, (3) increasing adoption of nutrition-related screening in clinical settings, and (4) enhancing access to dietary and lifestyle counseling. To estimate the long-term health and economic impacts of these interventions, we will use a validated, NIH-funded, dynamic microsimulation model that simulates diet-related disease progression in U.S. adults over the life course. The model incorporates demographic, behavioral, and clinical risk factors and is designed to evaluate long-term population health outcomes, medical expenditures, and intervention costs. Through comprehensive scenario, sensitivity, and subgroup analyses, we will assess variation in effectiveness and cost-effectiveness across population subgroups, considering differences in baseline risks (e.g., food insecurity) or vulnerability to the risk (e.g., effects of food insecurity on outcomes) or intervention’s effects across demographic subgroups. Our research team brings interdisciplinary expertise in policy evaluation, simulation modeling, nutrition science, and health economics. We are uniquely positioned to: (Aim 1) measure long-term population health effects of food and nutrition interventions; (Aim 2) estimate long-term effects on health across population subgroups; and (Aim 3) quantify economic impacts and cost-effectiveness. An independent dissemination aim will improve knowledge translation to end-users by legal and administrative feasibility analysis and developing a web-based platform, the National Food and Nutrition Policy Impact Simulator. This project responds to the need for actionable, policy-relevant evidence to inform national strategies to reduce diet-related disease and improve population health. Findings will support identifying food and nutrition ...