Among all these components protein has a different and very essential role to play to keep the body in shape and make it strong. The main function of protein is reviving the dead tissues and enabling the growth of cells. Another essential function performed by proteins in body is making of hormones in the body and other serums required by the body. Proteins from plants are as nutritious as animal proteins. The total calorie intake should comprise of 20 percent of it. Proteins are made of essential and non-essential amino acids.
A normal diet should contain 15-20% of protein. The intake of protein shouldn’t be more than 20% as suggested by the new researches. Protein contributes 4calories of every gram consumed by the body. The right combination of essential amino acids as per the Recommended Dietary Allowance (RDA) 1989 is: Isoleucine (10 mg), Lysine (12mg), Leucine (14 mg), Phenylalanine (14 mg), Methionine (13 mg), Threonine (7mg), Valine (10 mg) and Tryptophan (3.5 mg). These are those amino acids, which the body needs but cannot make them and are thus only made available to the body from food intakes comprising of these amino acids. And the protein needed by an infant is Histidine (28 mg). These amounts of proteins are taken in accordance with the body weight, per kilogram of it per day, by the body.
Requirement of protein depends on different factors like weight of the body, sex, age and the physical condition of the body. A normal human need for protein varies from that of the needs of an athlete or a body builder, or a person who is sick and lacks essentials required for a fit body. The body intakes essential amino acids that further help in making other non-essential amino acids required by the body to replenish the complete protein requirement of the body. The protein requirement of a body-builder is different from that of a normal workingman; the protein required by them is whey protein. Proteins from plants and from animals are the only outer sources of protein; milk has all the 8 different amino acids that the body requires for building muscles, hardening of bones and repairing cells. Eggs also provide complete protein, especially the white part of the egg.
An individual should take proper amount of protein, because any lesser than that or more than that can affect the body functioning adversely, which may result in body discrepancies. The amount of proteins suggested by physicians all over the world and by Recommended Dietary Allowance (RDA) has been agreed universally as the right intake of proteins for individuals with normal physical needs. The right combination of protein should be the proper combination of proteins from vegetarian food and non-vegetarian food. Vegetarian people are advised to take some dairy foods along with vegetables to keep the protein level in body at par. Dairy foods have high and good quality of proteins in them.