Meat as a Food 

Meat is one of the most important foods. It is usually the item around which the balanced meal is built. In studying the composition and the chemical constituents of meat, the role it plays in the diet will be understood. 

Protein. 

Meat is undoubtedly the most widely used of all animal proteins. This use of meat as a source of protein is scientifically sound because of the high biological value of its protein. The belief is no longer held that proteins from whatever source are of equal value in the diet. 

Dr. H. H. Mitchell makes this point clear in the following statement: "Even vegetable foods such as dried (navy) beans and cocoa, which are relatively rich in crude protein are unimportant as sources of protein in nutrition because of the enormous losses of nitrogen in the course of their utilization in digestion, or in metabolism, or both. Their high content of protein is deceptive and the conclusion that such foods are 'meat substitutes/ though frequently stated, must be considered erroneous. "Among the animal foods it is evident that meats and meat products are preeminent as sources of protein. Although the biological value of animal tissue proteins (nitrogen) is appreciably lower than those of eggs or of milk, the higher content of protein in animal tissues, either on the fresh or dry basis, offsets or more than offsets their greater losses in metabolism.''1

McCollum and Simmonds emphasize the same point: "It is surprising that proteins of all peas and beans are of low biological value. This means that they are not well utilized when they form the sole source of protein in the diet. This fact compels a revision of views formerly held concerning the importance of seeds of the leguminous plants. A few years ago it was generally taught that peas and beans were excellent substitutes for meats. . . . Proteins from one source, rich in certain digestion products which were furnished in but small amounts by proteins from another source might be combined, and each protein would enhance the value of the other. Unfortunately, the proteins of peas, beans and soy beans do not enhance to any marked degree the quality of the cereal grain proteins. In this respect these proteins are distinctly inferior to meat proteins."2 

Dr. Casimer Funk and Dr. Benjamin Harrow make the following statement about the use of meat as protein food: "Meat is the most popular protein food, but at the same time contains other food constituents. We find proteins in peas, beans, and cereals, though as a rule the proteins found in the plant world are not as 'complete' as those found in the animal world. This is a strong argument against the adoption of a strictly vegetarian diet."3

A survey of Table 3 will disclose the marked superiority of animal foods over vegetable foods as sources of protein. Another angle from which protein study is approached is the supplementary relations which exist between proteins from different sources. Proteins with the same amino-acid deficiencies will not supplement each other. Proteins from meats are decidedly valuable in enhancing the proteins of the cereal grains. This is due not only to the fact that meats and cereal grains do not have the same amino-acid deficiencies but also to the fact that the proteins from both of these sources are highly assimilable. 

Fat. 

Fat is a valuable constituent of food. It is used in the body to form fatty tissue and to furnish energy. Fat has a greater fuel value than any other food constituent. One pound of fat will yield two and one-fourth times as much heat as do proteins or carbohydrates. Meats, especially the fat meats, such as bacon and salt pork, are splendid energy foods.