Proteins - The Building Blocks
Muscles and other tissues are made up of proteins. Although protein contains the same amount of energy as carbohydrates (4calories per gram), it's primary function is the growth of these tissues. Because it is an inefficient source of energy, very little protein is used for fuel unless carbohydrate intake is limited or energy demands are extreme. In this case, protein is detoured from its main functions and is broken down for fuel. Eating adequate amounts of carbohydrates spares protein for building and repairing tissues and prevents the loss of lean tissue.
Lean meats, poultry without the skin, fish and eggs are excellent sources of protein. Other sources include beans, nuts and low-fat dairy products.
Fitness Nutrition Specialist.