Which of the following best describes energy expenditure?

• A. Calories consumed through meals
• B. Physical activity and metabolic processes that use energy
• C. Only exercise sessions
• D. Sleep duration

Answer: (B)

Energy expenditure is the total amount of energy the body uses in a day, including the energy for resting metabolic processes as well as energy spent during movement. It includes metabolism at rest, digestion and absorption of food, and calories burned through physical activity. The description that best fits is energy expenditure as physical activity and metabolic processes that use energy, because it captures both movement and the body's ongoing energy needs. Energy intake from meals describes calories coming in, not what the body uses; focusing only on exercise misses the resting metabolism and other energy uses; and sleep is only a part of energy use and doesn’t define the whole expenditure.