Which energy concept refers to the energy expended to digest, absorb, and metabolize nutrients?

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

Answer: (B)

The energy used to process a meal is called the thermic effect of food. After you eat, your body must digest, absorb, transport, and metabolize the nutrients, and this work requires energy. The thermic effect of food is a portion of your total energy expenditure and tends to vary with what you eat: protein causes the highest TEF because it takes more energy to convert protein into usable components, carbohydrates cause a moderate TEF, and fat causes the smallest TEF. In practical terms, TEF is roughly a modest share of daily energy use, with protein-driven processing often around 20–30% of the energy from protein, carbohydrates around 5–10%, and fats about 0–3%.

This concept is distinct from basal metabolic rate, which is the energy your body needs to keep basic functions like breathing and circulation going at rest; from the energy spent during physical activity, which is the calories burned through movement; and from adaptive thermogenesis, which covers changes in energy expenditure in response to environmental factors like cold or overfeeding.