seem to show that the body is as well, if
not better, nourished by a much smaller amount of proteid--not more than
two and one half ounces (60 grams) daily.(53)

While there is probably no necessity for the healthy individual's taking
his proteid, fat, and carbohydrate in _exact_ proportions (if the
proportions best suited to his body were known), the fact needs to be
emphasized that proteids, although absolutely necessary, should form but a
small part (not over one fifth) of the daily bill of fare. In recognition
of this fact is involved a principle of health and also one of economy.
The proteids, especially those in meats, are the most expensive of the
nutrients, whereas the carbohydrates, which should form the greater bulk
of one's food, are the least expensive.

*Effects of a One-sided Diet.*--The plan of the body is such as to require
a _mixed diet_, and all of the great classes of nutrients are necessary.
If one could subsist on any single class, it would be proteids, for
proteids are able both to rebuild tissue and to supply energy. But if
proteids are eaten much in excess of the body's need for rebuilding the
tissues, and this excess is oxidized for supplying energy, a strain is
thrown upon the organs of excretion, because of the increase in the
wastes. Not only is there danger of overworking certain of these organs
(the liver and kidneys), but the wastes may linger too long in the body,
causing disorder and laying the foundation for disease. On the other hand,
if an insufficient amount of proteid is taken, the tissues are improperly
nourished, and one is unable to exert his usual strength. What is true of
the proteids is true, though in a different way, of the other great
classes of foods. A diet which is lacking in proteid, carbohydrate, or
fat, or which has any one of them in excess, is not adapted to the
requirements of the body.

*Composition of the Food Materials.*--One who intelligently provides the
daily bill of fare must have some knowledge of the nature and quantity of
the nutrients present in the different materials used as food. This
information is supplied by the chemist, who has made extensive analyses
for this purpose. Results of such analyses are shown in Table 1 (page
126), which gives the percentage of proteids, fats, carbohydrates, water,
and mineral salts in the edible portions of the more common of our foods.

[Fig. 61]

Fig. 61--Relative proportions o