Foods are substances which when taken into the body yield energy on oxidation, build new tissue, repair old tissue and play an essential role in growth and nutrition. We know the oxidation of foods produces heat thus maintaining the body temperature and providing kinetic energy for work. Supplying bodily heat and energy and leaving waste materials behind the food is «burned up» in combination with the oxygen to be furnished by the air we breathe.
Scientists have studied the problem of food classification for many years. Foods are to be divided into two general classes. These are inorganic and organic foods. The former class includes inorganic salts and water. The latter class includes carbohydrates, fats and proteins. There are accessory foodstuffs called vitamins which are essential to growth and freedom from deficiency diseases1.