PROJECT SUMMARY The developmental origins of obesity begin in utero with growth and differentiation of adipose tissue. Fetal white adipose tissue accretion is highly variable and dependent on the maternal intrauterine environment. Unlike white adipose tissue, brown adipose tissue (BAT) has a high capacity for thermogenesis. BAT is present at birth and it is believed to support the critical function of thermoregulation in early postnatal life. Therefore, BAT may also influence the development of neonatal energy balance. Similar to white adipose tissue, it is hypothesized that development of BAT in utero is also influenced by maternal factors such as prepregnancy BMI and gestational weight gain. The overall research aims of this mentored F32 fellowship are to 1) identify maternal and neonatal factors that contribute to neonatal BAT and 2) to identify changes in neonatal BAT and to energy expenditure in response to a mild cold exposure. These aims will be accomplished by leveraging the NIH funded clinical trial of Dr. Leanne Redman (primary mentor) Healthy Mamas (R01DK124806). The long-term goal of the candidate is to develop an independent research program that focuses on the developmental origins of energy balance. To achieve this goal, the primary training objectives are to: 1) develop skills in clinical trial management and data collection for neonates and grantsmanship, 2) acquire theoretical and practical expertise in brown adipose tissue identification (anatomy) and activation (physiology) methodology, and, 3) acquire didactic and hands-on training in the physiology, clinical assessment, and interpretation of human energy expenditure. The research and training will take place at Pennington Biomedical Research Center, an exceptional research environment that offers endless opportunities and will be sponsored by world leaders in the field of energy balance: Drs. Leanne Redman (maternal energy balance), Eric Ravussin (energy expenditure), and Denis Blondin (BAT). Successful completion of this proposal will result in several first-authored publications and will generate a wealth of preliminary data for a competitive K01 application. This F32 proposal will not only serve as a valuable training opportunity to incorporate a balance of didactic, hands-on, and mentor directed learning, but also a novel and meaningful scientific contribution. This proposed fellowship provides the candidate with the opportunity to begin training as a developmental energy balance researcher and to launch an independent academic career.