What is protein
Proteins are simply large molecules composed of nitrogen and containing amino acids. Half of the dry matter of an adult is protein. Of this amount, one-third is in the form of muscle, one-third in bone and cartilage, one-tenth in the skin, and the rest in other tissues and in body fluids. Because these tissues regularly need additional proteins for maintenance, the body must have a regular supply of protein in the diet.
For the body to use protein, food must be broken into amino acids in the digestive tract. The amino acids are absorbed by the body and then resynthesized into proteins necessary for the body. The body requires a vast number of proteins, but they are all formed from the same pool of amino acids.
When we eat a source of protein, chemicals in the stomach act on the protein to liberate the amino acids. Thus protein foods and foods contain appreciable amounts of amino acids. Meat, dairy products, chicken, and fish are examples of protein foods.
There is also another type of commercially prepared protein food. This is the popular protein supplement which includes protein pills, liquids, and powders. They are made from such thins as skimmed milk powder, powdered liver, yeast, egg whites, beef organs, calcium caseinate, and soybean. Most brands carry wording on the label that is similar to “Super Protein” or “High Protein” and contain high percentages of protein with very small amounts of fat and carbohydrate.
What about protein quality? Are some protein foods better than others?
In order to select adequate sources of dietary protein, it is important that individuals understand the concept of protein quality. Proteins may be classified simply in two categories: high-quality or complete proteins and poor-quality or incomplete proteins. The high-quality protein has amino acid and human requirements than a poor-quality protein. Body or tissue proteins are composed of amino acids, some of which the body cannot synthesize. These must be provided in the diet. Consequently, the food that has the greatest amount of these essential amino acids present in it has the highest quality of biological value
The ultimate source or proteins is plant. Animals cannot “fix nitrogen in their tissue-like plants. They must obtain their proteins or nitrogenous compounds from plants or other animals that have consumed plants. Proteins from plant and animal tissue are not of the same quality because they do not contain the same amount or the same kinds of amino acids. It turns out that the food item which supplies the highest quality proteins for humans comes from animal tissues like beef, pork, fish, chicken, eggs, and dairy products. This is not surprising when a person realizes that the composition of animal tissues would be more similar to that of human tissues than the composition of plant tissues.
How much protein is needed each day?
What Happens If You Eat Too Much Protein?
Too much protein can result in liver or kidney disorders. The amount of protein that may put the patient at risk varies inversely with the degree of liver or kidney malfunction.
Studies counted on animals also suggest that excessive amounts of dietary protein may be damaging to the liver and kidney. The metabolism and excretion of these nonstorable protein loads impose serious stress and may cause excessive growth of the very important organs.
Most of the liquid protein diets sold over the country are not properly fortified with minerals particularly potassium. A deficiency of potassium can lead to sudden death. The liquid protein diet may also produce big shifts in body water and electrolytes, causing cardiac arrest.
Since bodybuilders and weightlifters are interested in developing muscular size and strength, they should consume extra protein. Right?
It does seem as though extra protein would be needed for building large muscles. Especially since muscles supposedly are made of protein. To look closely at this assumption, however, unravels some misleading statements. When chemically analyzed, a muscle contains over 70% water. Only 22% of the muscle is protein.
What does this mean? simply, it takes very little protein to produce a pound of muscle, particularly since so little muscular growth actually takes place within a given 24 hours period. A normal diet will supply more than enough protein to build muscles.
Although it is possible to exit on a diet of meat and a vitamin-mineral supplement for a period of time, it is surely not recommended. The almost complete abstinence from eating carbohydrates imposes a number of serious hardships on the body.
No single food provides all the essential nutrients. Any diet that contains large amounts of single food will tend to be unbalanced or deficient in one or more nutrients. The best diet will always include a wide variety of foods.