The part which the proteins should play in the balanced ration is the most serious consideration in arranging a diet. If insufficient protein is taken, the body cannot grow or build up the wornout parts; while, if too much is taken, the result is serious disease. As a matter of fact many of the so-called degenerative diseases are traced to too much protein in the diet. So the selection of protein foods involves considerable thought. Another cause for thought is that many foods analyze a large proportion of protein that is not digestible - and we live upon what we digest, irrespective of what we eat. Mushrooms, for example, contain a certain amount of protein, but it is in such form that the body cannot digest it all. The outer layers of certain grains contain considerable protein, yet, as it cannot be assimilated, the nutritional value of this part of the grain is chiefly in the mineral matter which is also present. As these foods contain a large amount of waste material, they are also of value as "ballast" in the diet.

The following foods may be roughly classified as proteins:

Beef, poultry, game, pork, lamb, mutton, veal, cheese, nuts, milk, eggs, fish, dried beans, peas, lentils and milk soups.

All dishes which consist largely of any of these foods also belong to this classification, so that the possibilities of presenting protein in the diet are considerable. Many housewives have the idea that only savory dishes, suitable for the main portion of a meal, are proteins, but this idea is erroneous. Any of these foods, whether in a sweet, a salad, or a soup, is a protein. For instance, dried lima-bean soup, chicken salad, escalloped beef, baked egg custard, cheese souffle, or nut croquettes are all proteins, and if they are not so considered in the menu, the body may rebel and become heir to the ills attending a diet too rich in protein. This is not difficult when the common error of serving meat three times a day is made. It is obvious that with so wide a variety of protein foods from which to choose there should be no trouble in planning menus in which meat figures but once a day.

The statement is frequently made that the protein value in three eggs, three ounces of cheese, two ounces of salted peanuts, or a pint of milk equals that in five ounces of meat. While this may be true, it is impracticable to serve many of these meat substitutes uncombined, for, unless they are supplemented by some food which serves as ballast, they do not contain a bulk equalling that of meat. Most people feel that the satisfying of hunger consists in eating until the stomach is full, and this cannot be done on a concentrated diet, as overeating and illness result. If the cheese is escalloped with coarse crumbs, the peanuts hash-browned with potatoes, the eggs creamed and served on toast, the milk solidified into junket or enforced with oatmeal or whole wheat crackers, the ballast will be supplied and the body satisfied. The reason that meat substitutes are not more generally used is probably because most women fail to grasp this point, and a single trial of the so-called substitutes, plain or not properly combined, convinces them that "their family would rather have meat" and they turn back to their former ways.

The selection of protein best suited to the menu depends largely upon the family. The more digestible types are advisable for those doing light work, the "heartier," or less digestible foods for those of greater activity.

The digestibility of a few more common foods may be noted roughly as follows:

Quickly Digested

(One to three hours)

Milk

Broiled tripe

Turkey

Broiled chicken, lamb chops and steak

Broiled, poached, scrambled and coddled eggs

Baked custard

Broiled trout, halibut and salmon

Boiled cod, halibut and salmon

Salt codfish, baked or creamed

Oysters, raw or baked in shell

Boiled beef

Slowly Digested

(Three to five hours)

Pork in all forms

Veal in all forms

Nuts in all forms

Cheese in all forms

Mushrooms

Pot-roast of beef

Casserole dishes

Hard-cooked and fried eggs and omelets

Stews

Fried meats of all kinds

All "made dishes" of meats

Fried fish of all kinds

Mackerel, sardines, canned salmon, and all fat fish

Lentils, peas and beans

This raises the most important point in connection with proteins - their cookery - for it is possible to make a food that is otherwise digestible difficult of digestion by improper cooking, and to make those so-called "indigestible" much more palatable and nutritious by the right treatment. To a considerable extent perfect digestion depends on perfect cooking, and on the same consideration hinges the greatest possibility for absorption of nutriment. Food that is not digested is wasted; a human machine clogged with the wastes of indigestion is inefficient. However, in searching for digestible foods any tendency to "pamper" or "spare" the digestive organs of a normal person should be avoided. The whole body needs exercise - the stomach, liver and intestines, as well as the legs and arms, and, while they should not be overloaded, they should not be given a diet of eggs, milk and predigested foods on which they will become weakened.

The cooking of all protein foods is alike in that they should never be subjected to high temperatures, as this has a hardening effect on the protein element, making it indigestible. If an egg, for instance, is boiled or poached in rapidly boiling water for four minutes, the white becomes opaque and leathery, while, if the time is slightly increased and the egg is immersed in water just below the boiling point, it becomes perfectly cooked, having a jellied, translucent appearance.

It may be given, then, as a rule, that eggs should always be cooked at the lowest possible temperature. If eggs are to be hard-cooked, the only way to avoid the unpleasant chemical changes brought about by the usual prolonged cooking is to put them on in cold water, bring them slowly to the boiling point, boil rapidly for ten minutes, then plunge at once into cold water to stop all further cooking. This is the only case when an egg, as a protein food, should be boiled. Scrambled eggs, as usually served, are leathery and indigestible, because they are turned into melted butter in a pan so hot that the eggs are not only coagulated immediately, but are fried as well. Properly, the mixture should be turned into a cold, thick frying pan, the lump of butter added, and the whole cooked so gently that the result is creamy. Fried eggs and omelets should also be cooked slowly. A perfectly fried egg cannot be prepared under five minutes, while an omelet of fair size needs ten. Custards and desserts of all kinds, containing eggs, should be surrounded by boiling water while cooking, as this keeps the temperature below boiling point. Otherwise they will "curd," or, in other words, the eggs will cook in lumps.

Fish consists of a considerable proportion of protein, yet there is probably no other food so maltreated. The majority of people "do not care for fish," but in how many cases is it ever served other than fried or boiled? If the former method is used, the delicate flavor and texture is usually overcome by the hot fat; if the latter, the fish is "cooked to death." If fish must be fried, let it be in deep fat. The high heat will immediately coagulate the outside protein cells, preventing the escape of juices, while the cold fish will reduce the temperature sufficiently to carry on the process slowly. In boiling (a misleading term) fish should be started in water just at boiling point; for, as the protein of fish is soluble in cold or merely warm water, it will otherwise be lost. If it be wrapped in a cloth and the complete cooking carried on at simmering-point (as with the boiled eggs), the fish will present a "jellied" appearance, be very tender and remain whole. If boiled rapidly, it is not only "cooked to pieces" but the breaking open causes the loss of both flavor and part of the protein. In boiling, the fish should be subjected to high heat only long enough to seal the outside. The same rule also applies to planking. In no case should the process be hurried.

Meats may be cooked in various ways, boiling, broiling, stewing, pot-roasting, braizing, roasting and casseroling being the most common. "Boiled beef," properly prepared, is one of the juiciest and most digestible of meats, but, like fish, it must never be actually boiled. Again, though different in appearance, meat contains practically the same protein as eggs and fish, and, if boiled, becomes tough and leathery. The protein of meats, like that of fish, is soluble in cold water, so they should always be plunged into boiling water to seal, or "sear," the pores, in order to preserve the protein, then simmered gently till done. In this way the juices will be retained and the meat become tender and gelatinized. In preparing a five-pound piece it will be necessary to increase the time of cooking about an hour over the old method. The fireless cooker is a successful medium for preparing tough meats, because it necessitates a slow process. The resulting stock will be thin and rather "flat," because the flavors have been retained in the meat, which is of first importance. In stewing, on the other hand, the meat and liquor are of equal importance; so the meat is immersed in cold water, and brought slowly to the simmering point, in order to make the broth of strong flavor. In this way the juices are divided between the meat and the broth, making the stew more palatable. Casserole cooking is merely baking a stew in an earthen dish. Pot-roasting is modified boiling, the meat being first browned or seared all over in fat to keep in the juices, then added, with the vegetables and spices, to boiling water sufficient to cover it half over. It should never boil.

In broiling or pan-broiling, meat should be subjected to heat sufficient to sear it quickly, then turned immediately to sear the other portions, lest the juices escape. As most meat for broiling is cut crosswise, the fibers containing the meat fluids are left exposed. Unless the searing be quick and complete, these juices will escape, the result being a flat, tasteless meat. If, however, the searing is thorough, and the meat is turned frequently, the juices run back and forth in the fibers, which expand with the heat until the meat assumes a puffy appearance. In roasting, meat is exposed to a very hot heat till seared, all over, then finished at a lower temperature.

Cheese is another protein that requires careful cooking. It consists largely of casein, the protein of milk, and, like all the other foods in this group, is rendered indigestible by high temperatures. This is the reason it disagrees with many. If baked, it should always be set in a pan of hot water; if in a rarebit or cheese sauce, it should be cooked in a double boiler; either method keeps it below the boiling point. In case it is to be added to soup or macaroni, the dish should be fully prepared before the addition, the heat being sufficient to melt the cheese. If served plain, it should be finely shaved, or cut in small pieces, and some bulky food should always accompany it.

Dried peas, beans and lentils should always be soaked several hours before cooking, thoroughly rinsed, and then simmered until tender. Again, it takes slow-cooking to make the protein digestible. A little baking soda, added while cooking, aids in softening the husks and overcoming the gases that frequently attend the eating of dried vegetables.