From the very prehistoric stage of the civilization of mankind, man has realized the indispensability of food for the building up of a healthy body and a sound mind. He is able to notice that people who are well-fed live longer and are stronger and they are able to do more work than those who do not have enough to eat. Yet it is only during the last 150 years that we are able to understand objectively and scientifically the important role that food plays in our daily life. Thanks to the recent scientific investigations that we are able to know clearly, the place of food in the growth of the human body, as well as in ending the body with energy.