By Flora Rose
Any person who has to choose the food that he is to eat himself or that is to nourish others should know at least a few simple principles of food selection. Food is too important in human welfare to be chosen in a haphazard way. Fortunately, recent scientific work on foods has done much to make it comparatively easy to acquire at least a practical simple working knowledge of food values.
The daily meals must supply three things:
1. Fuel. The body must be kept warm, and it must have some source of energy for the work which it must do. The greater the amount of work which the body has to do, the greater is its need for fuel. If the food does not supply sufficient fuel to do the work of the body, some of the body's tissue will be burned as fuel. If too much fuel food is eaten, the body may store some as fat or it may become upset by it.
2. Building materials. All the tissues of the body-muscles, nerves, bones, blood-cells-must receive a constant supply of those substances from which they are built. Children cannot grow without a liberal supply of building materials, and the tissues of grown persons will deteriorate if they are not furnished with sufficient building material to keep them in good repair.
3. Body regulating substances. The body not only needs fuel and building material, but it must also be supplied with substances which regulate its various activities and keep its machinery in good running order. These regulating substances are necessary to make the fuel burn normally, to help set the building materials in place, to aid in eliminating the wastes of the body, to enable the body to grow, and to keep its machinery running at all. If no foods were included to supply body-regulating substances in the daily meals, the body would soon become damaged.