The term meat includes the flesh of all animals used for food, as beef, veal, mutton, lamb, pork, poultry, game. Lean meat is almost a pure protein food.

Composition Of Meat

1. Muscle fibers, composed of proteins, extractives, inorganic salts, and water.

The principal protein is albumin. Muscle albumin is often called myosin.

The extractives are largely nitrogenous.

The mineral constituents in greatest abundance are phosphates and potash salts.

2. Connective tissue which binds together the muscle fibers, this consisting chiefly of a protein called collagen, which yields gelatin on boiling.

3. Fat interspersed between the fibers.

Nutritive Value

Meat is rich in nitrogenous elements and fats, and contains important salts, chiefly potassium and iron. It is easily cooked and improves in flavor during the process; requires less mastication and is more easily digested and assimilated than most vegetable food.

Meat is lacking in carbohydrates, and unless a large amount of fat is present, is to be regarded as a source of nitrogen rather than of energy. Since protein burns up faster than other foods, and very little of the nitrogen can be retained in the body, it is most advantageously used in small amounts along with plenty of fats and carbohydrates.

The most important food element in meat is the myosin or muscle albumin. The collagen belongs to a group of proteins often called gelatinoids or albuminoids, because, unlike the albumins, they cannot sustain life alone. They are able, however, to replace other proteins to the extent of two-thirds of the ordinary nitrogen requirement. In young animals, the connective tissue is soft, and the tissues are easily masticated; but in older animals it becomes very firm, is hard to chew and often escapes digestion unless softened or changed to gelatin by cooking.

The nitrogenous extractives have no nutritive value, and in fact, represent products either of waste (katabolism) or of insufficient oxidation. Unless promptly excreted, they may cause an excess of uric acid or other disorders. However, they bestow upon cooked meat its characteristic flavor and odor; in the stomach, act as stimulants to the secretion of gastric juice; and exert on the nervous system a stimulating influence similar to that of tea and coffee.

Digestibility Of Meat

Meat is easily digested, the degree of ease depending upon the following conditions: (1) The age of the animal when killed, with the exception of veal, the flesh of the young animal is more easily digested, but less nutritious than that of the older one; (2) the time the animal is kept before cooking; (3) the sex; (4) the care bestowed on the animal during life; (5) the quantity of fat. Lean meat is more easily digested than fat meat.

Absorption Of Meat

Meat is very readily absorbed and leaves little residue in the intestines; only 3 per cent. of meat taken is lost in the process of digestion.

Uncooked Meat

Ordinary raw meat is not quite as easily digested as cooked meat. Owing to color and flavor, it is not appetizing and could not be taken continuously. However, when chopped fine or scraped free from connective tissue, so as to be easily attacked by the digestive juices, it is more readily digested than cooked meat.