paration in the stomach, hence the nutrients of vegetables are not,
as a rule, as easily digested as those of animal foods.

231. Factors influencing Digestion.--There are a number of factors
which influence completeness as well as ease of digestion, as: (1)
combination of foods; (2) amount of food; (3) method of preparation; (4)
mechanical condition of the food; (5) palatability; (6) physiological
properties; (7) individuality of the consumer; and (8) psychological
influences.

232. Combination of Foods.--In a mixed ration the nutrients are
generally more completely digested than when only one food is used. For
example, milk is practically all digested when it forms a part of a
ration, and it also promotes digestibility of the foods with which it is
combined, but when used alone it is less digestible.[27] Bread alone and
milk alone are not as completely digested as bread and milk combined.
The same in a general way has been observed in the feeding of farm
animals,--better results are secured from combining two or more foods
than from the use of one alone. The extent to which one food influences
the digestibility of another has not been extensively studied.

In a mixed ration, consisting of several articles of food of different
mechanical structure, the work of digestion is more evenly distributed
among the various organs. A food often requires special preparation on
the part of the stomach before it can be digested in the intestines, and
if this food is consumed in small amounts and combined with others of
different structure, the work of gastric digestion is lessened so that
the foods are properly prepared and normal digestion takes place. The
effect which one food exerts upon the digestibility of another is
largely mechanical.

233. Amount of Food.--Completeness as well as ease of digestion is
influenced by the amount of food consumed. In general, excessive amounts
are not as completely digested as moderate amounts. In digestion
experiments with oatmeal and milk, it was found that when these foods
were consumed in large quantities the fat and protein were not as
completely absorbed by the body as when less was used, the protein being
7 per cent and the fat 6 per cent more digestible in the medium ration.
Experiments with animals show that economical results are not secured
from an excess of food.[5] Some individuals consume too much food, and
with them a restricted diet would be beneficial, while others err in not