Aptly enough, the word "protein" is derived from a Greek root meaning "of first importance," and protein which constitutes about one-fifth of an adult's body weight, is the basic material of life. Muscles, organs, bones, cartilage, skin, antibodies, some hormones, and all enzymes (the compounds that direct chemical reactions in cells) are made of protein.

Proteins are constantly being broken down in our body. Most of the amino acids are reused, but we must continually replace some of those that are lost. This process is known as protein turnover. Our need to keep this process going begins at conception and last throughout life. Without dietary protein, growth and all bodily functions would not take place.

When we eat foods containing protein, the digestive system breaks it down to the constituent amino acids, which enter the body "pool" of amino acids. Each cell then assembles the proteins it needs using the building blocks available. If, however, one or more of the needed amino acids is in short supply or not available at all, others that may be on hand cannot be utilized to form a protein. This is why it is important to eat a diet rich in proteins.

Many "experts" differ on the amount of protein needed in the diet. Some suggest very low amounts; some suggest much higher amounts.

The following protein requirement chart can be used only as a guideline for determining the protein requirement. One may need more, or may be slightly less. Our requirement depends on the percent of body fat, weight and the physical activity one does. The higher the activity level, the more one will need to increase the dietary protein intake to repair and rebuild muscle.

While undergoing any type of severe stress (including the stress of cancer, burns, radiation exposure, or pregnancy), one may need more. If you are susceptible to infections, the requirement may increase.