Eggs contain everything that is necessary for the growth and maintenance of the body, but are particularly lacking in calcium, and are unbalanced with respect to certain other food principles. Thus, eggs are very rich in fats and related substances, and are nearly lacking in carbohydrates. A diet exclusively of eggs, or in which eggs are a prominent constituent will favor putrefactive processes in the alimentary tract. For these reasons, eggs are to be regarded as articles which should be of secondary importance so far as amount is concerned. They have, however, most exceptional dietary properties which makes it desirable to use them where the item of expense is not prohibitive.

The fats of eggs are fully comparable with butter fat as a source of the fat-soluble A (42), and egg yolk is at least comparatively rich in water-soluble B, and in water-soluble C. The proteins of egg are believed to be of high biological value. In the developing chick there is considerable absorption of lime from the shell, and in this way the shortage of calcium in the organic content of the egg is made good. When we eat eggs, we cast out the shell and thus take the part which is deficient in lime.

It will be seen, therefore, that eggs may have an important place in enhancing the quality of a cereal, tuber and meat diet, but that they cannot logically be considered a substitute for milk. They should be eaten with a diet rich in carbohydrates to discourage the tendency for putrefaction in the intestine, which they favor, and should be used to confer palatability on other foods rather than as a prominent constituent of the food supply.