Chart Of Composition Of Foods Percentage Of Nutrients Of Edible Portion, I. E., Without Bone, Etc

Digestibility Of Food

The accompanying tables showing the comparative digestibility of some common foods are therefore merely a general statement, and represent average results.

Table Of Digestibility And Fuel Value Per Pound Of Nutrients In Different Groups Of Food Materials. (Atwater.)

Table Of Comparative' Digestibility, Commencing: With The Most Digestible And Ending With The Least Digestible Of Meats And Other Common Animal Food

Oysters.

Soft-cooked eggs.

Sweetbread.

White fish, boiled or broiled, such asbluefish, shad, red snapper, weakfish, smelt. Chicken, boiled or broiled. Leanroast beef or beefsteak. Eggs, scrambled, omelette. Mutton, roasted or boiled. Squab, partridge. Bacon. Roast fowl, chicken, capon, turkey. (From W. Oilman Thompson).

Tripe, brains, liver.

Roast lamb.

Chops, mutton or lamb.

Corned beef.

Veal.

Ham.

Duck, snipe, venison, rabbit, and other game. Salmon, mackerel, herring. Roast goose. Lobsters and crabs. Pork. Smoked, dried, or pickled fish and meats in general.

It should be noticed that the fuel value obtained in the body from the various classes of foods is somewhat less than the theoretical amount mentioned on page 35, because they are not completely digested and assimilated nor completely oxidized in the body. The following values are used in the U. S. Government reports as representing average conditions:

Fuel Value In The Body

Proteid, fuel value, 4 calories per gram, or 1,820 calories per pound. Fats, fuel value, 8.9 calories per gram, or 4,040 calories per pound. Carbohydrates, fuel value, 4 calories per gram, or 1,820 calories per pound.

Fuel And Energy Foods

The foods that are particularly useful in furnishing heat and energy for the body, the carbohydrates and fats, are frequently called the fuel foods, although proteid can act as fuel just as readily as can these. Since the proteids, however, have a more important function and are most expensive, the other foods are used as proteid sparers. The amount of these fuel foods that is to be taken depends not upon the amounts present in the body, but upon the amount of heat and energy to be produced. This depends, in general, on the size of the body and the amount of muscular activity.

The Body And An Engine

The comparison is frequently made between the body and a locomotive, the food representing the fuel, the air taken in through the lungs representing the draft, the waste matters of the body corresponding to the smoke and ashes from the engine fire. In many ways this is a helpful comparison, but we need to keep in mind the essential differences between the human body and the mechanical engine as well as their likeness. Combustion in the body is much slower than in the machine, and is therefore not accompanied by light, though by the oxidation of the same amount of fuel the same total amount of heat is produced.

Oxidation in the body takes place not in one central cavity, but in every living tissue and not only furnishes the heat to keep the body warm but, in some unknown way, gives directly muscular energy, nervous energy and the energy for all the functions of living. Moreover, unlike any engine, the body builds and repairs itself constantly. If the building food is not sufficient in amount the waste of tissue proceeds faster than its repairs, and there is a constant loss of body substance. The body can store fuel food as fat for use in case of need.