Caloric expenditure refers to the total number of calories the body uses to maintain basic functions and perform physical activities. This includes the energy required for vital processes like breathing, circulation, and cell production, known as the Basal Metabolic Rate (BMR). Additionally, calories are burned during activities such as walking, exercising, and even digesting food. Factors influencing caloric expenditure include age, gender, weight, and muscle mass. For instance, individuals with more muscle tend to burn more calories at rest compared to those with higher fat percentages. Understanding caloric expenditure is essential for managing weight and overall health.