What is protein?

Shakes, tuna and chicken are a bodybuilder's best friend, and as such, protein is often thought of as only a gym rat's food. Protein is an important and essential nutrient for everyone. It has several functions including (but not limited to): providing energy, building/repairing tissue and structural support (skin and hair).

Protein's Role

Protein is the building block of all the tissue in the body including hair, nails, skin and muscle. As it relates to exercise, protein provides the body with the material it needs to repair damaged muscle tissue.

Exercise causes tiny tears to the muscle. The body treats these tears as injuries and repairs them during rest. In addition to rest, the repair process requires nutrients such as: vitamins, minerals, fats, carbs and proteins. The repair process makes you bigger, stronger and faster.

Amino Acids

Protein is made up of amino acids. There are two types of amino acids; some the body can produce (non-essential amino acids) and others that need to be ingested (essential amino acids). There are nine essential amino acids (isoleucine, valine, leucine, tryptophan, threonine, methionine, arginine, lysine, histidine) that must be provided to the body through proper nutrition.

Complete vs. Incomplete Proteins

Proteins are made up of a specific sequence of amino acids; there are an almost endless amount of unique proteins. If a protein contains all nine essential amino acids, it is called a complete protein. Proteins lacking one or more of the essential amino acids are called incomplete proteins.

To build and repair tissue, the body needs access to all nine essential amino acids. This does not mean you should only eat complete proteins; ensure your intake comes from a wide variety of foods.

Sources of Protein

Complete proteins are found mainly in animal products while incomplete proteins are found in plant products. Because many animal products are high in saturated (unhealthy) fat, it is important to find lean sources of complete proteins.

Lean Sources of Complete Proteins:

  • lean meats (chicken, turkey, lean cuts of beef)
  • low-fat dairy
  • seafood
  • soy
  • protein supplements

Unhealthy (fatty) Sources of Complete Proteins:

  • pork
  • red meat
  • whole dairy

Sources of Incomplete Proteins:

  • grains (bread, rice, pasta)
  • nuts/seeds
  • fruits/vegetables (contain small amounts of protein)

It is unnecessary to get 100% of your needs from complete proteins. During digestion, proteins are broken down into individual amino acids. The body can use essential amino acids from incomplete proteins to produce complete ones. You can build muscle with incomplete proteins if your intake comes from a wide variety of foods (especially important for vegetarians).

How much protein do I need to eat each day?

The Bottom Line

Protein's main function is to build and repair tissue. The amount of muscle needing to be repaired is not dependent on how much protein you eat, rather the amount of damage caused during exercise. Protein contains calories, which in addition to building muscle, can also be stored as fat, causing unsightly weight gain.