The third variety of food is the carbohydrates, and of these there are two kinds, starches and sugars. Starch is the white material of the grains and tubers; the principal food element of bread and cereals, rice, potatoes, bananas, and many prepared substances such as corn-starch, tapioca, farina and macaroni. Starchy foods compose probably half the diet of the average human being. In my own case, they compose about one-sixth, so you see to what extent my beliefs differ from the common. Starch is not really necessary in the diet at all. I have a friend who is subject to headaches, and finds relief from them by a diet of meat, salads, and fresh fruits exclusively. The first thing that excess of starch or sugar does is to ferment in the system, and cause flatulence and gas. But strange as it may seem, if the excess of starch is perfectly digested and assimilated into the system, the condition may be worse yet, because you may have a great quantity of energy-producing material, without the necessary mineral elements which the body requires in the handling of it. If you cremate a human body and study the ashes chemically, you find a score or more of mineral salts. You find these in the blood, and no blood is normal and no body can be kept normal which does not contain the right percentage of these elements. It is not merely that they are needed to build bones and teeth; they are needed at every instant for the chemistry of the cells. Every time you move a muscle, you fill the cells of that muscle with a certain amount of waste matter. You may prove how deadly this matter is by binding a tight cord about your arm, and then trying to use the arm. We are only at the beginning of understanding the subtle chemistry of the body; but this much we know, the cells transform the waste products, and they are thrown out of the system as ammonia, uric acid, etc.; and for this process the blood must have a continual supply of many mineral salts.