Which components make up total energy expenditure?

• A. Basal metabolic rate, Thermic effect of food, and Physical activity
• B. Resting energy, Digestion energy, Sleep energy
• C. Basal metabolic rate only
• D. Food energy only

Answer: (A)

Total energy expenditure is the sum of three main parts: the energy your body uses at rest to keep essential functions, the energy required to digest and process the food you eat, and the energy you burn through all physical activity. The first part is the baseline energy needed for things like breathing, circulating blood, and keeping cells alive. The second part, the thermic effect of food, accounts for the calories you burn to digest and metabolize nutrients from meals. The third part covers all movement, including intentional exercise and everyday activity such as walking, standing, and fidgeting. Together, these components add up to what you expend in a day.

The other options don’t fit because they either include energy you don’t expend (like “food energy” refers to calories in rather than calories expended) or break out components in nonstandard ways (such as separating sleep energy or using only the resting baseline). Basal metabolic rate alone is just the resting portion, and omitting the thermic effect of food and physical activity means you’re not accounting for all energy used.