Protein is used by the body to build, repair, and maintain muscle and organ tissues by repairing and building cells, aid in the formation of antibodies, they work in conjunction with enzymes and the hormonal system, help transport oxygen and participate in muscle activities.

When Protein is digested it is broken down into a number of amino acids (Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, Valine, Alanine, Arginine, Aspartic Acid, Cysteine, Glutamic Acid, Glutamine, Glycine, Histidine, Lyrosine, Proline, Serine, Taurine and Tyrosine), These amino acids are divided by definition into two main groups. The first group is termed essential amino acids and are required by the body to make the second group called non-essential amino acids. Don't be fooled by the term non-essential these proteins are very important to sustaining a healthy and vital life. A deficiency of any one essential amino acid can cause a corresponding deficiency in some or all of the non essential amino acids.

Some foods contain what is called complete protein, that is, they provide all the amino acids necessary to produce usable protein. Examples of these foods would be milk, eggs, meat, fish, and various vegetable products, such as soybeans. But even these foods contain differing amounts of usable protein per weight.

The suggested RDA for Proteins and Amino Acids varies from 0.8 to 1.5 grams per Kilogram body weight per day. I would like to point out to the reader that the RDA of any Nutrient is based on the absolute minimum to sustain life.

I have not been introduced to any research documents that proves conclusively that over consuming proteins can adversely effect a persons health (with the exception of weight gain). I have read and heard from many so called professionals that the over consumption of protein can lead to kidney problems and other complications but I have as of yet to read any such reports or literature supporting this claim. I've even read in some literature that males should consume 63 grams a day and female should consume 50 grams a day. This is fine if you only weigh 138 lbs for a male and 110 lbs for a woman and live a sedentary life style. In my personal experience I have consumed between 100 grams to 400 grams of protein on a daily basis for up to 10 months at a time while training. I found that 100 grams a day is a good maintenance intake and 400 grams a day was more then sufficient to grow on, my gains on 400 grams a day were both muscle mass and fat gains. My protein consumption consisted of both whole foods and supplements because I found that trying to eat 400 grams of protein a day from normal food sources was next to near impossible and time consuming as well. So in a nutshell the over consumption of protein in my opinion will led to fat gains only and not to some sort of metabolic disease, excess protein is converted into glucose or stored as fat... its as simple as that. My recommendation as well as others in the field of sports nutrition is to start out with 1 gram per pound of body weight and adjusting from there to met your needs. If you are an athlete and you don't make any gains from this then you should also look at the rest of your dietary and lifestyle habits. Arguably I've been taught to consume no more the 35 grams of protein per meal as this is the most that the gut (reportedly) can handle at any given time, with the remainder going to waste, fat or glucose. So breaking up your meals into smaller meals more often is of great benefit and aids in maintaining a positive state of muscle growth as well as making it easier on your body. I know of many athletes including myself that try to eat about every 3 hours, I've even been known to get up in the middle of the night for a glass of milk or a bowl of cottage cheese.

Below you will find information on quality food and supplement choices to help you met your basic protein - amino acids requirements.

Eggs are such a good source of quality protein that they are used as a basis of comparison for rating the protein quality of other foods, with eggs given an arbitrary value of 100.

As you can see from this list, foods like rice, potatoes, and beans give you considerably less usable protein than eggs or fish. Because these foods lack one or more of the essential amino acids they cannot satisfy the body's protein needs. You can, however combine two or more sources of this low-quality protein (incomplete protein) to obtain high-quality, complete protein. Combining protein in this way is useful too because it usually involves eating foods that are very low in fat, and this can contain fewer calories then most complete protein sources.
Since each of the sources of incomplete protein lacks certain essential amino acids, you need to be very specific in your food combinations in order to end up with complete protein. For other sources of Protein please consult the USDA website.