Principles of Energy Homeostasis

Mammals have evolved complex mechanisms to obtain energy from food; store excess energy in the forms of glycogen, fat, and protein; and utilize energy efficiently for vital functions. Obesity develops when energy intake exceeds energy expenditure. While obesity treatment is mostly focused on reducing food intake, studies suggest that increasing energy expenditure through physical activity and adaptive thermogenesis is an important strategy for weight loss and maintenance of health. This chapter will describe fundamental concepts of bioenergetics and provide a framework for understanding the pathogenesis and treatment of metabolic syndrome.