PROJECT SUMMARY Through this COBRE application, we seek to establish the Center for Childhood Obesity Prevention. The goal of the Metabolism Core C is to provide support for metabolic studies, including exercise studies and biological sample analyses, for projects in the Center. It is recognized that suboptimal nutrition and exercise are important factors in the development of obesity, and that improvement of these factors are vital for the reversal of obesity and its corresponding disturbances in metabolism. The structure of this improvement is however debated, e.g., can exercise alone, without changes in bodyweight, improve obesity related metabolic disturbances. The Metabolism Core (MC) includes a physical activity facility for controlled studies of exercise and substrate metabolism, a special procedure/testing facility, and an analytical lab for analyses of biological samples. The MC will assist and mentor the junior investigators in the performance of metabolic studies, including use of stable isotope tracer techniques to measure metabolic rates, and will assist in design of future fundable studies of metabolism in obesity. Among the primary junior investigator projects, focus will be on the response of lean and obese children and also obese pregnant women, to nutritional interventions (probiotics, amino acids or protein). The effects of interventions on insulin sensitivity, fat oxidation, whole body protein turnover (synthesis and breakdown), and plasma and liver lipid content/hepatic steatosis, will be determined. The MC will also serve to educate and support the COBRE junior investigators in measurement of physical activity and biological responses in community/field studies. Thus, the core adds to the uniqueness of the grant in that lab studies and community studies of obesity are bridged in a translational manner. The Metabolism Core is NEW to the revised application.