The term "metabolism" refers to the complex biochemical processes that convert food into energy. It encompasses all chemical reactions within the body, including the breaking down of nutrients for energy (catabolism) and the synthesis of new compounds necessary for growth and repair (anabolism). Metabolism also determines how efficiently the body utilizes stored energy and regulates vital functions like temperature and hormone balance. Factors influencing metabolism include age, muscle mass, activity level, and overall health, impacting individual energy needs and weight management.