IN the present state of our knowledge we can say with the greatest assurance that a complete and balanced diet is one that shall satisfy the following specifications:<br />1.It must furnish enough energy to keep the body going.<br />2.It must furnish material for growth and for replace ment of tissue waste.<br />3.It must furnish enough water.<br />4.It must furnish enough inorganic mineral salts.<br />5.It must furnish vitamins.<br />6.It should furnish enough bulk.<br />7.It must help to maintain the neutrality of the body.<br /><br />The purpose of this book is to amplify these specifications and to attempt to persuade you of their validity. In order to do so we shall recount the findings and particularly the methods of that wonderful new science of nutrition, examine the observational and experimental data upon which it bases its conclusions so that we may realize how important those conclusions are for the welfare, health and happiness of mankind.<br /><br />Our knowledge of diet and the chemistry of food and nutrition has enlarged so much in the last few years that it may be said to be among the most exact branches of biologic science. And this mass of exact information is so practical, touches so closely the interests of every one of us, that it is a duty for every one to acquaint himself with this body of knowledge.