Protein, carbohydrates and fats, are the three primary macronutrients. Found in virtually every body part, proteins are the main building blocks of the body. They’re used to make muscles, tendons, organs and skin. Proteins are also used to make enzymes, hormones, and neurotransmitters that serve as important functions for life. All these factors play an important role in the body, and getting a balance of each is important for optimum health as well as results in the gym.