Final answer:
Twenty-four-hour energy expenditure includes resting energy expenditure, physical activity, and the thermic effect of food, but not metabolic rate as it is already encompassed within the other components. Metabolic rate refers to the total energy expenditure, thus it is not a separate factor in the calculation.
Step-by-step explanation:
Twenty-four-hour energy expenditure is calculated using resting energy expenditure (REE), physical activity, the thermic effect of food (TEF), but not metabolic rate directly, as it is encompassed within REE and TEF. REE, which is also called the basal metabolic rate (BMR), represents the rate at which the body uses energy to sustain life when at rest, and accounts for about 70-75% of the total energy expenditure. Physical activity contributes approximately 20% to total energy expenditure, and the thermic effect of food, which is the energy used for digestion, absorption, and metabolizing of food, contributes about 10%.
Conversely, metabolic rate is a general term that includes the total energy expenditure, of which REE is a component, and hence the metabolic rate is not calculated separately when determining total daily energy expenditure. Instead, it is reflected in the measurements of both REE and TEF.