158 BULLETIN 414, U. S. DEPARTMENT OF AGRICULTURE. 
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." 1 
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 life, 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 little 
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 efficiency, 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 all 
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," 
