Nutrition.
It is not within the scope of this book to deal with the science of
nutrition; but a few general principles may be given which concern the
effect upon the system of the different classes of food. Animal food
requires a considerable quantity of oxygen for its complete
combustion. Meat in general has a more stimulating effect upon the
system and is more strengthening than vegetable food. There is,
however, a tendency to eat too much meat, and when its effects are not
counter-balanced by free outdoor exercise, it causes biliousness and
sometimes gout and other troubles. Albuminous foods can be eaten
longer alone without exciting loathing than can fats, sugars or
starches. A carbonaceous diet taxes the excretory organs less than
animal food. Meat is not necessary to life. Nitrogenous food man must
have, but it need not be in the form of meat. The estimate commonly
given is, that meat should occupy one-fourth and vegetable food
three-fourths of a mixed diet, but in many cases the meat eaten is
much in excess of this allowance. The proper association of different
foods always keeps healthy people in better condition; there are
times, however, when it may be necessary to abstain from certain
articles of diet. It may be well to bear in mind, that the protein
compounds can do the work of the carbohydrates and fats in being
consumed for fuel, but the carbohydrates and fats cannot do the work
of protein in building and repairing the tissues of the body. As
already stated, a mixed diet is the only rational one for man. An
exclusively vegetable diet, while it may maintain a condition of
health for a time, eventually results in a loss of strength and power
to resist disease. Therefore it is necessary to understand the
approximate value of each class of food in arranging the daily
dietary.