the energy gained by proteins and carbohydrates differs from the energy gained by fats. proteins and carbohydrates both give 4 kcal per gram fats give 9 kcal per gram mass of proteins - 2 g energy given by proteins - 2 g x 4 kcal/g = 8 cal mass of carbohydrates - 20 g energy given by carbohydrates - 20 g x 4 kcal/g = 80 cal mass of fat - 1 g energy given by fat - 1 g x 9 kcal/g = 9 cal total energy = 8 + 80 + 9 = 97 kcal energy = 97 kcal
