1. Thermic effect of food: 1 calorie of protein is not the same as 1 calorie of carbohydrates or fats. The body requires energy to digest food. Fats require only 0-3% of the total energy from food to get digested. Carbohydrates require 5-10% of energy while proteins require 20-30% of energy. Therefore, the macronutrient profile (protein, carbohydrates and fats ratio) play an important role in weight loss.