ABSTRACT Childhood obesity is highly prevalent, difficult to treat and prevent, and of major health and economic consequence. Lower income children and children of Black, Latinx, and Native American race/ethnicity experience a disproportionate burden of obesity as compared to higher income and White or Asian children. Evidence suggests that economic and environmental factors, many driven by structural racism, underlie racial and income disparities in obesity. These structural factors are often acknowledged as potential root causes of obesity and obesity disparities; however, they are also recognized as difficult to intervene upon. Policy interventions are one option for affecting change upon these potential root causes. Using a natural experiment approach, we have an opportunity to leverage a recent policy change—the Community Eligibility Provision (CEP) of the Healthy Hunger-Free Kids Act of 2010—to assess the degree to which providing free meals to all children in high poverty schools affects obesity prevalence. The CEP was passed in 2010 and allows schools in high- poverty school districts to provide universal free meals (breakfast and lunch) to all children in the school without requiring individuals to sign up for the free and reduced lunch program. The goal is to increase participation in school meals and ultimately reduce both food insecurity and obesity. The program is targeted at lower- and lower-middle income children, many of whom were not receiving free- and reduced-price lunches despite being eligible. Because the CEP is targeted to high-poverty schools, focuses on a social determinant (income constraints) and is a non-agentic policy (i.e. children and their families do not need to do anything extra to receive the benefits), this policy has high theoretical potential to decrease obesity and possibly decrease obesity disparities. CEP could be expected to impact child body weight by prompting individuals to substitute healthier foods for unhealthier food and by providing two meals a day at no cost, thus affecting child BMI through indirect pathways of increased disposable household income. This increase in disposable income could lead to decreased food insecurity, decrease parental stress, and/or could potentially be used for health promoting behaviors, such physical activity or purchasing of healthier foods in the household, each of which has been associated with obesity. CEP represents a significant change in school policy and an expansion of social safety nets, but scant scientific literature exists on the health impacts of CEP. The proposed study aims to comprehensively assess the impacts of CEP on obesity outcomes through using robust data and methods for causal inference in order to assess: 1) the impact of CEP on obesity 2) impact of CEP on potential mediating mechanisms 3) heterogeneities in impacts on obesity by race/ethnicity and income 4) impacts on population- level obesity disparities.