Woman's Institute Library of Cookery
10. In order to select food material that will meet the requirements just set forth, three important matters must be considered; namely, the substances of which it is composed; its measure of energy-producing material, or what is called its food, or fuel, value; and its digestion and absorption. Until these are understood, the actual cost of any article of food cannot be properly determined, although its price at all times may be known.
However, before a study of any of these matters is entered into, it is necessary to know just what is meant by food and what food does for the body. As is well understood, the body requires material by which it may be built and its tissues repaired when they are torn down by work and exercise. In addition it requires a supply of heat to maintain it at normal temperature and provide it with suffici