Obesity ensues when calorie intake exceeds energy expended. Hitherto, up-regulating energy expenditure is a relatively unexplored avenue. This project will address 3 facets of energy expenditure (fat, muscle and neural control). Understanding how sex and steroids act in concert to regulate energy expenditure will pave the way towards developing novel anti-obesity agents. This work will delineate mechanisms that underpin gender differences in the regulation of body weight.