Obesity disparities among American Indian (AI) youth exist and, to date, there are limited interventions available to successfully address weight and consequential outcomes for AI youth. The high prevalence of youth-based obesity is alarming, placing them at disproportionate risk for adult obesity and obesity-driven metabolic diseases including diabetes, cardiovascular disease, high blood pressure, and stroke. In addition, although cancer has traditionally been considered a distinct spectrum of disease, increasing evidence supports the importance of metabolic disturbances in the cause of cancer. This underscores the urgent need to address excess weight in AI youth to protect against obesity-related diseases, including cancers, in later life. Schools provide concentrated time with students, provide up to 50% of daily food intake, provide physical activity opportunities, and teach health education. Tribal schools participating in the federal school meal programs are required to adopt and implement a School Wellness Policy (SWP) that sets clear expectations for nutrition education, foods served and sold, physical activity and physical education practices. Despite widespread research on the implementation of SWPs in U.S. schools, their generalizability to schools in tribal communities remains limited, highlighting a major gap in understanding how tribal schools adopt and implement SWPs. The goal of P2 is to engage and partner with 3 separate tribal schools on Navajo Nation. The objectives are to implement an established health promotion curricula among 4th graders after completing formative research to strengthen SWPs at each school, to establish a baseline for each school. We will use a train-the-trainer approach to establish structured lessons and practices, as warranted, for physical education instructors and food service personnel, for example. The health promotion curricula for the students will include culturally tailored health education focused on nutrition and physical activity. We hypothesize that participation in our health promotion efforts will strengthen school-specific SWPs, including structured physical activity, and that 4th grade youth will increase their knowledge and exhibit improved behaviors for fruits and vegetables consumption and increased physical activity. Specific Aim 1 – Complete formative assessments at three K-8 Navajo Nation tribal schools to understand the capacity and resources of each to implement a train-the-trainer approach to establish structured lessons and practices, as warranted, for physical education instructors and food service personnel. Specific Aim 2 – Assess changes in the knowledge and behaviors of Navajo youth exposed to a culturally appropriate health promotion curriculum during the academic school year. Changes in fruits and vegetables consumption and physical activity will be compared between 4th graders to 3rd graders. Specific Aim 3 – Assess changes in SWPs at each participating school using t...