By C. F. Langworthy, PH. D.

Office of Experiment Stations.

In this article a number of the terms used in discussing food are defined and some of the principles of nutrition are briefly stated. The average composition of a number of the more common American foods is quoted as well as the commonly accepted dietary standards. With the aid of such data, the nutritive value of any given diet may be computed and its comparative value ascertained.

Ordinary food materials, such as meat, fish, eggs, potatoes, wheat, etc., consist of:

Refuse

As the bones of meat and fish, shells of shellfish, skins of potatoes, bran of wheat, etc.

Edible Portion

As the flesh of meat and fish, the white and yolk of eggs, wheat flour, etc. The edible portion consists of water and nutritive ingredients, or nutrients. The nutritive ingredients are protein, fats, carbohydrates and mineral matters.

The water, refuse, and salt of salted meat and fish are called non-nutrients. In comparing the values of different food materials for nourishment they are left out of account.