Dis moi ce que tu manges, je te dirai ce que tu es. {Tell me what you eat, and I will tell you what you are.)

- Brillat Savarin: Physiology of Taste.

THE word "rations" may be defined as a daily food allowance. If meals formed from such rations contain the food nutrients - proteins, fats, carbohydrates, and mineral matters - in the proper proportions, they are balanced meals, and the rations are balanced rations. Such rations and such meals would fully supply the body's needs for energy, growth, and repair.

On the other hand, meals containing only one class of food nutrients would not be balanced. For instance, a diet of starch foods, as bread, cereals and potatoes, or a diet of protein foods, as meat, beans and cheese, would quickly impair health and efficiency, unless balanced by the addition of foods from other classes. Evidently, then, the housewife should know the different kinds of foods depended on by the body for its various needs, and how those needs can be met with the food materials at her command. With such knowledge, she can plan daily menus intelligently and maintain her family in health.

In a previous chapter the human body was compared to an engine, because, like the engine, it burns fuel which yields heat and energy, from which in turn it derives its ability to perform work. Here the comparison ends, because the body uses food not only to develop energy, but also to build and repair its own structure.

For this twofold purpose, nature has provided an abundant variety of food materials. All these foods, when burned in the body, yield heat and energy, and nearly all build up muscular tissue which is used in body-building. The foods which are highest in body-building and repair value, as meats, eggs, or meat substitutes, are grouped as protein foods, and the foods which are highest in fuel value, as fat, starch, and sugar foods, are called carbohydrates. Still another class of foods, chiefly vegetables and fruits, provide bulk and mineral matters.