With flexible dieting, you count the grams of each macronutrient in the food you eat, rather than a total number of calories. The calculator on this page will provide an optimal macronutrient ratio based on your goals—fat loss, muscle gains, or maintenance.
Macronutrients give us energy Although each of these macronutrients supplies the energy needed to run body functions, the amount of energy that each provides varies. Carbohydrates and proteins each provide 17kJ/g whereas fats provide 37kJ/g. 1 kilojoule (kJ) = 1000 joules.
Nutrients are environmental substances used for energy, growth, and bodily functions by organisms. Depending on the nutrient, these substances are needed in small amounts or larger amounts. Those that are needed in large amounts are called macronutrients. There are three macronutrients required by humans: carbohydrates, lipids, and proteins.
Proteins are also important in the diet for many reasons. For example, protein is the major constituent of most cells, making up more than 50% of the dry weight. Also, protein defines what an organism is, what it looks like, and how it behaves, because the body is made of thousands of proteins.