Proteins are considered to be “building blocks” in that they are responsible for the growth and repair of tissue in the body. All enzymes are made of proteins. Proteins are involved in the production of many hormones and are necessary to maintain the immune system and fluid electrolyte balance. They are also involved in the transport of nutrients throughout the body and across cell membranes and are broken down into their amino acids for energy when there are insufficient carbohydrates and fats available. Proteins provide your body with 4 calories per gram.