Which component of energy expenditure represents energy used to maintain basic physiological functions at rest?

• A. Basal metabolic rate
• B. Thermic effect of food
• C. Physical activity
• D. Adaptive thermogenesis

Answer: (A)

Basal metabolic rate is the energy your body needs at rest to keep basic physiological functions going, such as breathing, circulation, kidney and brain activity, and cellular maintenance. It reflects the minimal energy required to sustain life and is the largest portion of total energy expenditure for many people who are sedentary. TEF, the thermic effect of food, is the energy used to digest and absorb nutrients and accounts for a smaller share. Physical activity energy expenditure varies widely based on activity level, and adaptive thermogenesis refers to small adjustments in energy use in response to cold exposure or overfeeding. In short, basal metabolic rate represents the energy required to maintain essential bodily functions while at rest.