Modified Project Summary/Abstract Section Nationally, 73.6% of adults are overweight or obese. Rural populations and people living in households with limited financial resources have high rates of obesity. The greatest differences in obesity prevalence between urban and rural counties are in the southern United States. Arkansas has the sixth highest proportion of rural population (~41%) and the third highest obesity prevalence (37.4%). The CDC estimates 18.5% of children age 2-19 in the US are obese. Arkansas has the third highest rate of obesity for high school students (22.1%) and the fifth highest rate for children in ages 10-17 (20.2%). Obesity contributes to increased diabetes incidence, cancer incidence and mortality, and cardiovascular disease incidence and mortality among rural communities. This application seeks funding to evaluate a Comprehensive School Nutrition Enrichment Intervention (CSNEI) for the first time in rural schools. The primary research question is: “Compared with similar school districts that did not implement the CSNEI, does the CSNEI intervention yield improved obesity prevention outcomes among rural K-12 students?” We will conduct a matched-pairs cluster randomized trial with pre-test and repeated post-tests in 6 school districts, 3 implementing CSNEI and 3 matched comparison school districts. The evaluation will include ~11,500 students in 6 school districts: ~5,750 from CSNEI school districts and ~5,750 from matched comparison school districts. The study will explore heterogeneity of treatment effects for age and economic standing to understand effects on populations with higher contextual risk for obesity. Our specific aims are: Aim 1.A Evaluate the effects of a CSNEI on students’ relative BMI change over time. Aim 1.B Evaluate the short-term and long-term effects of a CSNEI on the nutritional quality of food served in school meals. Aim 1.C Evaluate the short-term and long-term effects of a CSNEI on students’ consumption of food served in school meals. Aim 1.D Evaluate the short-term and long-term effects of a CSNEI on students’ skin carotenoid levels, as an indicator of fruit and vegetable intake. Aim 2 Conduct an implementation study to document challenges and facilitators of CSNEI implementation in rural schools. We will complete the first implementation study of a CSNEI in rural schools, which will provide critical information to ensure successful implementation of similar interventions in school districts and will be an innovative step to accelerate translation of evidence into broad practice. Existing paradigms for the study of comprehensive school nutrition interventions do not appropriately address the needs and potential challenges of rural children, particularly those living in households with limited financial resources. This study will fill critical gaps by rigorously evaluating a CSNEI in rural schools with high proportions of students eligible for free and reduced-price meals (>50%); employing a ma...