Which of the following lists the three components of total energy expenditure?

• A. Basal metabolic rate, digestion energy, energy expenditure during sleep
• B. Resting metabolic rate, digestion energy, physical activity energy
• C. Resting metabolic rate, energy required for the thermogenic effect of digestion, energy expenditure associated with physical activity
• D. Resting metabolic rate, thermogenesis energy, metabolism during rest

Answer: (C)

Total energy expenditure is the sum of three parts: the energy used at rest to keep basic bodily functions; the energy cost of processing the food we eat (thermogenic effect of digestion); and the energy burned through all physical activity, including intentional exercise and everyday movement. Resting metabolic rate represents the energy needed at rest, the thermogenic effect of digestion accounts for the energy required to digest and metabolize nutrients, and energy expenditure from physical activity covers all activity-related calories burned. This trio—resting metabolic rate, the thermogenic cost of digestion, and activity-related energy expenditure—matches how TEE is defined. Other choices blur or duplicate components (for example, energy use during sleep is part of resting metabolism, not a separate component; the term thermogenesis energy is imprecise; and metabolism during rest overlaps with resting metabolic rate).