It has been stated that "a quart of milk, three-quarters of a pound of
moderately lean beef, and five ounces of wheat flour contain about the
same amount of nutritive material;" but we pay different prices for
them, and they have different values for nutriment. The milk comes
nearest to being a perfect food. It contains all the different kinds
of nutritive materials that the body requires. Bread made from wheat
flour will support life. It contains all the necessary ingredients for
nourishment, but not in the proportion best adapted for ordinary use.
A man might live on beef alone, but it would be a very one-sided and
imperfect diet. Meat and bread together make the essentials of a
healthful diet. In order to give a general idea of food economy, it
will be necessary to deal briefly with the functions of the various
food principles. As our bodies contain a great deal of muscle, the
waste of which is repaired by protein found in such food as lean meat,
eggs, cheese, beans, peas, oatmeal, fish, etc., a supply of these
articles must be considered in purchasing the daily supply. Fatty
tissue (not muscle) serves as fuel, therefore the value of such foods
as butter, cream, oils, etc., is apparent. Carbohydrates form fat and
serve as fuel and force producers; these come in the form of starches,
sugars,--vegetables and grains being the most important. In being
themselves burned to yield energy, the nutrients protect each other
from being consumed. The protein and fats of body tissue are used like
those of foods. An important use of the carbohydrates and fats is to
protect protein (muscle, etc.) from consumption. "The most healthful
food is that which is best fitted to the wants of the user: the
cheapest food is that which furnishes the largest amount of nutriment
at the least cost: the best food is that which is both healthful and
cheap." By referring to the various charts a fair estimate of food
values may be obtained.