What is the thermic effect of food (TEF) and its impact on daily energy expenditure?

• A. TEF is the energy used to digest, absorb, and metabolize nutrients; it accounts for about 5–10% of daily energy expenditure.
• B. TEF is the energy expended during sleep.
• C. TEF is the energy stored as fat after meals.
• D. TEF is the energy expended during physical activity.

Answer: (A)

TEF is the energy the body uses to digest, absorb, and metabolize the nutrients from the food you eat. After a meal, processes like breaking down proteins, carbohydrates, and fats, transporting nutrients, and converting them for use or storage require energy. This post-meal energy cost adds to your daily energy expenditure and is typically about 5–10% of the day’s total calories, though it can vary with what you eat—protein generally has a higher thermic effect than fats or carbohydrates. TEF is one piece of total daily energy expenditure, alongside your resting energy needs and energy spent through activity. It’s not the energy used during sleep, not energy stored as fat after a meal, and not the energy burned during deliberate exercise.