PROJECT SUMMARY Black Americans experience a disproportionate burden of obesity, one of the most significant public health challenges of the 21st century. Obesity is a major risk factor for multiple chronic conditions, including diabetes, hypertension, osteoarthritis, and depression, and is associated with a lower quality of life and shortened life span. Despite decades of public health interventions to address this problem, racial disparities in obesity persist and, in some cases, are widening. Substantial evidence shows that neighborhood environments, including segregation, deprivation, and food environments are associated with obesity risk and that these neighborhood characteristics vary systematically between Black and White populations. However, a critical scientific gap remains in understanding the root cause of obesity among communities of color – structural racism. The impact of structural racism vis-à-vis historical racialized policies and urban planning decisions on current day inequitable food environments and obesity disparities has received little systematic investigation. We propose to examine three historical racialized policies and practices, starting in the late 1930s – redlining, “slum” clearance, and highway placement – that have been hypothesized to have cemented residential racial segregation and maintained an advantaged status of White populations by limiting commercial, housing, and economic opportunities afforded to Black populations. To our knowledge, no studies have investigated these racialized policies as structural determinants of obesity disparities. Our aims are to: 1) determine the extent to which cumulative exposure to redlining category (red, yellow, blue, green), “slum” clearance, and highway development is associated with contemporaneous and longitudinal change in racial composition, economic indicators, and food environments of neighborhoods; 2) examine the historical and contemporary sociopolitical context of these three racialized policies through qualitative analysis of city comprehensive plans, newspaper media, and key informant interviews; and 3) examine the extent to which cumulative neighborhood-level exposure to these three racialized policies is associated with increases in BMI and risk of obesity. We are proposing a short-term, developmental R21 research grant to test the feasibility of linking newly compiled spatial and contextual urban planning and policy data with the Multi-ethnic Study of Atherosclerosis (MESA) cohort, which contains in-depth, longitudinal health data for people who were initially recruited from six cities. Findings from this work will be consequential for refocusing scientific attention on upstream causes of obesogenic environments and obesity disparities, and identifying structural solutions to advance racial equity in obesity prevention. In the future, we will build on this developmental grant (R21 proposal) with additional cohorts that include BMI and diabetes health data in ...