HOME ECONOMICS AND EDUCATION 563 



chief purposes of cooking. The first is to change the mechanical con- 

 dition so that the digestive juices can act upon the food more freely. 

 Heating often changes the structure of food materials very mate- 

 rially, so that they are more easily chewed and more easily and 

 thoroughly digested. The second is to make it more appetizing by 

 improving the appearance or flavor, or odors. Food which is attract- 

 ive to the taste quickens the flow of saliva and other digestive juices, 

 and thus digestion is aided. The third is to kill by heat any disease 

 germs, parasites, or other dangerous organisms it may contain. This 

 is often a very important matter, and applies to both animal and 

 vegetable foods. (Dept. Agr. F. B. 142.) 



MEATS. 



Studies of the food habits of people living in the temperate and 

 warmer regions of the world, where animal and vegetable foods are 

 both found in abundance and where there is opportunity for choice, 

 show that, while vegetable foods cereals, succulent vegetables, and 

 fruits compose the greater part of the bulk of the diet, animal 

 foods dairy products, eggs, meat, and fish almost invariably enter 

 into the bill of fare. For many reasons it seems fair to conclude, 

 with the majority of the physiologists, that this widespread habit is 

 the result of experience and that it has its foundation in bodily 

 needs. From the earliest times, in fact, man has used animal foods, 

 and his whole body structure is adapted to the use of such articles, 

 of diet. 



The value of meat as food depends chiefly on the presence of 

 two classes of nutrients, (1) protein or nitrogenous compounds, and 

 (2) fat. The mineral matter it contains, particularly the phos- 

 phorus compounds, is also of much importance, though it is small in 

 quantity. Protein is essential for the construction and mainte- 

 nance of the body and both protein and fat yield energy for muscular 

 power and for keeping up the temperature of the body. Fat is espe- 

 cially important as a source of energy. It is possible to combine the 

 fat and protein of animal foods so as to meet the requirements of 

 the body with such materials only, and this is done in the Arctic 

 regions, where vegetable food is lacking; but in general it is con- 

 sidered that diet is better and more wholesome when, in addition to 

 animal foods, such as meat, which is rich in proteins and fats, it 

 contains vegetable foods, which are richest in sugar. 



According to statistics compiled in the office of experiment 

 stations, meat furnishes about 16 per cent of the total food consumed 

 in the ordinary American family, about 30 per cent of the protein 

 desirable in the average diet, and 60 per cent of the energy-produ- 

 cing fats. It is possible to obtain all of the necessary protein and 

 energy from other materials but it' is doubtful if it would be either 

 desirable or agreeable for the average person. Exactly how much 

 meat should be eaten is a difficult matter to determine; probably 

 if one meat dish is served a day, and other materials supplying 

 protein, such as milk, eggs, beans, or similar foods, are also used, 

 there is little danger of getting too much meat or too little protein. 



