What are the commonly-reported TEF values for protein?

The correct answer reflects the commonly-reported thermic effect of food (TEF) values for protein, which are typically in the range of 20-30%. This high TEF for protein is due to the fact that protein requires more energy for digestion, absorption, and metabolism than carbohydrates and fats. When people consume protein-rich foods, the body expends significant energy in breaking down amino acids, incorporating them into proteins, and processing nitrogen. This increased metabolic activity results in a higher percentage of caloric expenditure associated with the intake of protein.

While other macronutrients have lower TEF values—carbohydrates generally have a TEF of about 5-10%, and fats are even lower—protein stands out for its higher thermogenic effect. This characteristic has implications for weight management and nutritional strategies, as foods high in protein can contribute to a higher overall calorie expenditure through the TEF. Understanding these values is essential for those seeking to optimize their diets for weight management or muscle preservation.