So long as there are enough fuel and food, but not too much, and so long as all the debris is carried away, there is health. But let this process be thrown out of balance and there will be disease. The food intake is seldom too small, though the digestion is frequently so poor that not enough good food gets into the blood. Old age is largely due to overeating and eating the wrong kinds of food. This is how overeating causes premature aging, when it does not kill more quickly: When too much food is taken, too much is absorbed into the blood, provided the nutritive processes are active. Then all the food in the blood can not be used for repair and fuel. The balance must either be excreted or stored away in the body as deposits. If this storing takes place in the joints, the result may be rheumatism or gout and at times even a complete locking of the joints (anchylosis). If it is stored in the walls of the blood-vessels they become hard and unyielding. No matter where deposits take place, some of them will be found in the walls of the blood-vessels. When these vessels grow hard they decrease in caliber. The result is that the heart is compelled to work very hard, but even then enough blood is not forced through the vessels. The circulation becomes sluggish. The blood in the various parts becomes stagnant.

Then insufficient good oxygen and first-class nourishment are brought to the parts and not enough waste is carried away. Now the billions of cells of which the body is composed are constantly bathed in poisonous blood. The result is lowering of physical tone, or degeneration, of the whole body. The hands and the feet suffer most at first from the poor blood supply and become cold easily. Those who suffer constantly from cold hands and feet should know that they are aging, although they may be but twenty years old.

Such a condition as this often gives rise to varicose veins in the legs. The feet are so far away from the heart, and it is such a long upgrade return of the blood, that the circulation in the lower extremities easily becomes sluggish. The flabby, relaxed tissues and the hardened blood-vessels allow the blood to stagnate. This is why senile gangrene is so common in the feet and so often fatal.

The brain gets a copious blood supply, yet the hardening of the arteries often deprives this organ of its necessary nourishment. Then the higher faculties begin to abdicate. If the hardening is extensive senile softening of the brain may take place. This is always due to a lack of pure blood. Sometimes the arteries are brittle enough to break. Baldness is another symptom of physical decay. The hair follicles are not properly nourished, for the arteries have become so contracted and the tissues of the scalp so hardened that there is not enough blood to feed the hair roots. Baldness begins on top of the head, generally the only part affected, because it is farthest away from the blood supply. Baldness is also partly due to man's headwear. Women are rarely bald. There is a saying that there are no bald men in the poorhouse. Even if this were true, it would not be very consoling, for the bald heads on the street cleaning forces are numerous.

Overeating also causes premature aging because if results in fermentation in the alimentary tract. The acids produced cause degeneration of various tissues, having an especially bad effect on the nervous system, which reflects the evil to other parts of the body.

It is well to bear in mind how this comes about: First there is overeating; too much food improperly prepared is taken into the blood stream; this makes the blood impure; deposits, causing hardening of the tissues and reduction of the lumen of the vessels, are formed; the blood grows more impure and the circulation sluggish; the tissues are constantly bathed in impure blood, causing further degeneration. When a certain point is reached nature can tolerate no more and life flits away.

Those who wish to remain young must give some thought to the selection of their food, especially if they are hearty eaters. If only sufficient food is taken to keep the body well nourished it does not make much difference what is eaten, provided it contains sufficient of fresh foods, for when only enough food is taken to supply fuel and repairing material, the food will all be used and none is left to ferment in the digestive tract and form deposits in the body. The body will then keep itself clean, or at least the formation of deposits takes place so slowly that it is hardly perceptible. This can be compared with the process taking place in the flues of a boiler. Stoke properly and they remain clean. Choke the firebox with an excess of coal and the combustion is so incomplete that the flues are soon filled up and the grates are often burned out. Just so with the body: Feed too heavily and the digestive organs are burned by the abnormal amount of acid produced and the blood-vessels are filled with debris.

As most people lack the self-control to eat a normal amount of food, they should select foods that are compatible and that are not too concentrated. Too much meat causes degeneration of all parts of the body and hardening. Too much starch causes acidity and hardening. The fruits and the light vegetables have a tendency to overcome these degenerating processes.