158 BULLETIN" 414, U. S. DEPARTMENT OF AGEICULTUEE. 



who are vegetarians, exemplifies the effects likely to accrue from foods 

 deficient in proteins: "It is better to sit than to walk, to lie than to 

 sit, to sleep than to wake, and death is best of all."^ 



Dietary studies have shown that in communities where there exists 

 a generally low condition of mental and physical efficiency, thrift, and 

 commercial success, there, too, may be found a low proportion of 

 proteins in the diet. As examples of this there are pointed out the 

 negro and poor white of the South and the Italian laborer of southern 

 Italy, all of whom are far down the scale as regards their sociological 

 conditions and commercial enterprises and whose diet is very low in 

 protein. Yet when ''hog and hominy" are generally supplemented 

 by a more liberal diet consisting of milk, eggs, meat, cheese, cowpeas, 

 and beans their general condition and productive powers have been 

 observed to increase markedly. 



It is not denied that it is quite possible to maintain fife, a certain 

 degree of health, and a measure of strength on a diet somewhat low 

 in protein, especially if the foods are selected carefully, have httle 

 waste, and are calculated to supply all the needed protein "building 

 stones"; but the object to be attained is to provide that food which 

 is best for the eflS.ciency, economy, and general welfare of the body. 



FATS AND CARBOHYDRATES. 



The fats are contained principally in such foods as butter, oleomar- 

 garine, lard, salad oil, fat salt pork, bacon, and fresh meats and fish, 

 while the carbohydrates include the sugars and starches and form 

 the principal constituents of foods derived from plants. These foods 

 can not build tissue, but they maintain the heat of the body and fur- 

 nish energy to carry on the vital processes and for work and activity. 

 The vegetable or plant foods also contain a considerable amount of 

 indigestible material which affords no nourishment, but furnishes the 

 bulk necessary to stimulate the flow of digestive juices and give the 

 walls of the intestine something to work upon. If the food were aU 

 of such a character that it could be absorbed as total nutriment the 

 bowels would not function properly and serious consequences would 

 follow. 



MINERAL MATTER OR ASH. 



Mineral salts are required by the body for bone formation and other 

 physiological processes. A generous and varied diet is much more 

 likely to supply the required kinds and amounts of these essential 

 constituents than is a diet restricted in quantity and variety. Fresh 

 green vegetables and fruits are not of great value as tissue-building 

 foods or energy producers and are not suitable to use as substitutes 

 for the more substantial foods, but they contain considerable amounts 

 of mineral salts, which are as essential to the health of the body and 



1 D. McCay, "The Protein Element in Nutrition," 



