The term "metabolism" refers to the set of chemical reactions in the body that convert food into energy. It encompasses all metabolic processes, including catabolism (breaking down molecules for energy) and anabolism (building up complex molecules from simpler ones). Metabolism affects how quickly the body uses energy, contributing to weight management and overall health. Factors such as age, muscle mass, and physical activity levels influence individual metabolic rates, making it a key consideration in nutrition and fitness.