Man is able to adjust himself to greatly varied levels of protein consumption, and the protein may be exclusively animal or vegetable in origin or of any mixture of these.
During fever and following injury there is a considerable loss of protein, and during convalescence, the total intake of protein is frequently raised above normal levels. For this restoration of wasted tissues animal protein Is considered to be superior to vegetable protein.
Where economic circumstances permit there is a tendency to raise the intake of animal protein to the region of 60 percent of the total protein. Because of the many complicating factors involved, it is not yet known to what extent this tendency is determined by a real need for animal protein and other dietary essentials associated with animal protein.
But important considerations are the attractive flavor, its easier assimilation, and the variety of ways in which it can be cooked. It has also been suggested that animal proteins form a more suitable mixture with other dietary principles from the standpoint of metabolism.
There is a general association of good physique, endurance and virility in racial groups with diets relatively rich in animal protein, and a general absence of these qualities where the diet is very low in animal protein or devoid of it, but many other factors, particularly heredity, may be operative.
In general, the animal proteins are superior to vegetable proteins for building human tissues, so they are called ‘first-class’ proteins. Vegetable proteins or ‘second-class’ proteins are used by the body to supplement those obtained from animal sources.
So it is essential for us to include some first-class proteins every day. The first-class proteins consist of milk, cheese, meat, fish and eggs. Dried beans also contain valuable amounts of protein and if they are used with one of these foods, such as meat or fish or a cheese sauce, they will make the animal protein foods go further and will make a nutritious dish.