O.K. So, proteins are extremely important molecules in the body. But how are proteins made / acquired?

Let us consider the route food takes once it enters the body. Keep in mind that food contains many nutrients; however, protein is the subject of our discussion.

Protein digestion begins in the stomach and ends in the small intestine. For protein to be absorbed it must be broken down to readily absorbed forms, i.e., amino acids and small peptides. Once absorbed, based on priority and demand amino acids are transferred to different locations. To make a complex process short and basic, inside cells amino acids are once again put together (In appropriate combinations) to make the necessary proteins. Some of these proteins are retained in the cell for intracellular use and some are exported. Even though this may sound straight forward, there is one important condition to protein synthesis.

Proteins are made of about 20 amino acids, 9 of which are essential; must be obtained from the diet. The remaining 11 are nonessential; can be synthesized by converting one amino acid into another in the liver. Although nonessential amino acids can be manufactured by the body, they must still be present and in proportion to the essential amino acids in order for the body to maintain normal metabolic functions. All 20 amino acids must be present for protein synthesis to take place. If one’s diet is deficient in even one of the essential amino acids, protein will not be made, and since protein is not stored in the body, all the other amino acids are either converted to fat and stored or simply excreted. Fortunately, it is not difficult to obtain all 20 amino acids in every day diet. Animal protein is likely to contain all the essential amino acids and is regarded as complete protein. Plant protein often lacks some and is known as incomplete protein. Foods such as rice, potatoes, nuts, and grains contain essential amino acids but in lesser quantities than animal proteins. Nevertheless, protein requirements in vegetarian diets can be safely obtained through a combination of complimentary plant proteins that work synergistically to produce the necessary amino acid balance.

How much protein must one’s diet contain? The recommended daily allowance (i.e., RDA) for protein is based on what an average 154 pound male would require under normal conditions. These requirements are established to ensure that a particular individual would be able to receive the amount of protein necessary to repair and replace tissue proteins. Individual characteristics, such as, size, growth periods, pregnancy, lactation and activity level have considerable effects on protein RDA. Type of protein consumed and certain medical conditions, such as, surgery, hemorrhaging, prolonged illness, burns, injuries and excessive tissue breakdown during extreme exercise or starvation also change the true value of Protein RDA. The factors that result in loss of body protein dictate one to increase their dietary protein. On the other hand, excessive amount of protein in one’s diet may alter fluid balance and place additional stress on the liver and kidneys.

The RDA for protein is 0.8 gm/kg/day.

This may be a good place to begin but, for strength athletes and those interested in muscle hypertrophy, an allowance for making gains in skeletal muscle tissue with training is necessary and, for endurance athletes, an allowance for covering potentially important rise in nitrogen losses due to exercise is appropriate. These allowances vary from one individual to another because of genetic variability and all the different factors mentioned above. Failure to consider all the factors involved would lead to inefficient training, slow or no progress at all. Note that this is a principle applied to all aspects of training.

High protein diets may lead to:

• Calcium depletion
• Fluid imbalance;
• extra work for liver and kidneys
• Eventual hunger;
• uncontrollable cravings for carbohydrates
• Slower metabolism
• Weight rebound
• Energy loss

Protein deficiencies in adults may lead to:

• Lack of energy and stamina
• Mental depression
• Weakness
• Poor resistance to infection
• Impaired healing of wounds
• Slow recovery from disease
• Slow or no recovery from exercise

Let us bring our discussion to an end by addressing a frequently asked question: Is going on a high protein diet the answer to losing "weight"?

You must agree now that eating a high protein diet for the purpose of losing fat and/or gaining lean body mass is simply wrong. (see above for disadvantages of high protein diet) Initial weight loss from a high protein diet is primarily due to loss of body fluids. In addition, a high protein diet is a low-calorie diet in disguise eventually unable to satiate the user. This often leads to uncontrollable eating behavior and concurrent weight gain. Keep in mind that any amount exceeding 25% of total calorie intake would be considered high. For the majority of people, there is no advantage to high protein intake, especially if fat-loss is the main goal. It is all about the number of calories consumed.