Macronutrients are the basic building blocks of nutrition. These building blocks include proteins, carbohydrates, and fats. They serve as your body's energy source and "building material." Energy is measured in units of calories (cal), sometimes called kilocalories (kcal).
Proteins and carbohydrates provide your body with about four calories per gram. Fats, on the other hand, provide nine calories per gram. While it is not typically counted among the three main macronutrients, do note that alcohol will also provide your body with about seven calories a gram.
If you are aiming for a lean and muscular physique, your macronutrient distribution should vary depending on whether your goal is body fat loss or building muscle. Generally, you should consume about 0.3-0.45 g of fat and 0.7-1.15 g of protein per pound of body weight. If you are dieting, you should orient yourself more towards the upper protein value and the lower fat value. The remaining calories are filled with carbohydrates according to your calorie needs.
You can calculate your calorie requirement with our calorie calculator.
Furthermore, macronutrients ensure that your body is able to perform all of its usual functions. Protein and fats are especially essential. Protein provides for the maintenance and building of cells, including in your muscle tissue. Protein is the basic building block for your muscles.
Protein also positively affects the functioning of your organs, your blood circulation, and your immune system. Protein is responsible for many enzymatic processes in your body. An increased protein intake, therefore, only brings advantages. However, your body does not have a protein store. If you supply your body with more protein than it needs for its functions, it converts the excess protein into carbohydrates (glycogen) or energy.
Carbohydrates are your body's energy source. To use the energy obtained from carbohydrates, your body breaks down the complex carbohydrates. This results in monosaccharides, which are simple sugar molecules used by your body.
Unlike protein, carbohydrates are not essential because excess protein can be converted into energy. Besides, your body can also get energy from fats. However, for muscle building, it is optimal to supply your body with carbohydrates, as full glycogen stores are essential for your performance in training.
Fats are also essential because they are involved in important bodily functions. These include the maintenance of your hormone balance and your immune system.