For the latter two meals of the day lunch and dinnerour natural dietthat is, the normal diet that average people eat will consist of soup, meat, one or two vegetables, a salad and a dessert. For many people lunch and dinner are more or less close duplications of each other. For others lunch is a very skimpy affair, consisting of a salad and a cup of coffee; or fruit; or a sandwich and a glass of milk.
At any rate, we will consider just one meal, assuming the other one to be similar, and therefore not requiring separate discussion.
The soup may or may not have any nutritional value. A clear soupbouillon–has none. Its value is as a stimulant to digestion arouses interest through smell and taste, and starts the digestive juices. Heavier soupscream soups, stock soups, cucumber soup, stews, vegetable and oyster stewsmay have almost enough nutritional value for a full meal. They are easily digested and relieve fatigue, just the thing after a hard day’s work.
Next the moot question of meat. Is meat part of the natural diet of man? Some think not and restrict themselves to vegetables, getting their animal protein out of milk and eggs.
On the contrary, it is quite certain that man’s digestive apparatus is well designed for the use of meat. Even including the teeth, which are more canine than ruminant in structure. The digestive juices of the stomach are exclusively for the purpose of protein digestion. And one of the most important digestive enzymes of the pancreas is for the same purpose, carrying out protein digestion in the intestine.
So much for digestion. For nutritionthe use of foods for building materials in the bodythere is even stronger evidence in favor of meat. The body must have proteins for building materials. Now proteins are made up of a combination of chemical structures known as amino-acids. The vegetable proteinsfound in peas and beans and corn and wheat and nutscontain certain amino-acids, but consistently are lacking in certain amino-acids found in animal proteins. And these latter are absolutely essential for the growth and maintenance of animal bodies. (And the body cannot build these from other chemicals. They must be furnished completely formed in the diet.)
To illustrate, two of these amino-acids, named tryptophane and lysine, are certainly essential in this sense. If young rats are fed exclusively on zein, an amino-acid found in vegetables, as the sole protein food, and a sufficient diet in all other respects, they not only cease to grow, but begin to lose weight. If now tryptophane is added to this diet they maintain their weight. If lysine is now added they begin to increase in growth and weight at a normal rate.
Of course, these essential amino-acids can be found in milk and eggs. But for most of us the most economical place to obtain them is from meat, and we must conclude that meat is part of a. natural diet.