This section is from the book "The Hygienic System: Fasting And Sun Bathing", by Herbert M. Shelton. Also available from Amazon: The Hygienic System Vol III Fasting and Sun Bathing.
The dangers of fasting are so slight as to be almost negligible or insignificant. When Purinton declared that "an extreme fast, say from twenty to forty days, is just as apt to wreck a man as it is to rescue him, unless, as I have mentioned before, it is properly conducted and completed," he plainly had in mind the many mistakes that the ignorant and inexperienced can and often do make, both during the fast and in breaking the fast. Books on fasting list a number of contra-indications for fasting. These need clarification. They follow:
(1) Fear of the fast on the part of the patient. Fear may kill where the fast would be of distinct benefit. If fear of the fast can be overcome there is no reason why it should not be instituted.
(2) Extreme emaciation. In such cases a long fast is impossible. A short fast of one to three days may often be found beneficial, or a series of such short fasts with longer periods of proper feeding intervening may be found advisable.
In extremely emaciated patients I do not favor pushing the fast to the return of hunger, but favor a process of careful nursing with one or more short fasts. Whereas, Carrington points out, that such patients may die before the return of hunger, I am convinced from experience, that with a careful nursing program and but limited fasting, these patients may be restored to health in many cases that would otherwise die.
I have repeatedly fasted such cases, even for as much as twenty-two days at a time; always with distinct benefit. Indeed, the fast is often the only thing that will enable these cases to overcome their emaciation.
(3) In cases of extreme weakness or of extreme degeneration. Even in many such cases a series of short fasts, as mentioned before, may often be beneficial. In the latter stages of consumption and cancer, the fast can be of no value except to relieve the patient's suffering. It may prolong life a few days. Fasting is of distinct benefit in the earlier stages of both of these conditions, however.
Great weakness is not always a danger signal; rather it may often prove to be a "false alarm." More often than otherwise, weakness signifies poisoning or a crisis. It is essential that the weakness be considered in union with all other symptoms present. Indeed, this is true of all the danger signals. No one of them, considered by itself, constitutes an evidence of real danger. Carrington regards periods of great weakness that are often seen in fasting patients as crises, or periods of great physiological change going on in the body. He says that "the fact that hitherto weak hearts are actually strengthened and cured by fasting proves conclusively that any such unusual symptoms, observed during this period, denote a beneficial reparative process, and not any harmful or dangerous decrease or acceleration, due to lack of perfect control by the cardiac nerve." In this connection I may add that I have never seen a death from "heart failure" during a fast, although I have seen many crippled hearts make complete recoveries during a fast. Prostration and weakness are part of the process we call disease, and are not due to the lack of two or three meals. Hence it is that, as the patient returns to normal, strength returns even when no food has been eaten or digested.
It has been pointed out in the preceding pages that great weakness is not necessarily a bar to fasting; that it is in such cases that we often see the greatest gains in strength.
(4) In cases of inactive kidneys accompanied by obesity. In such cases it is said that the tissues may be broken down faster than the kidneys are able to eliminate them. This I doubt. I know of no reason why the tissues of the body should be used up faster at this time than at other times. It is true that there is increased elimination during the fast but this is not so great as to constitute a great burden upon the kidneys. I have repeatedly fasted cases of Bright's "disease" and cases of kidney stone, kidney abscess and pyelitis with distinct benefit in all such cases.
(5) In marked "deficiency diseases." Some advocates of fasting do not advise fasting in these conditions; but hold that, since they are due to food deficiencies, these patients need a changed diet rather than a fast.
It was shown in previous pages that fasting is distinctly beneficial in rickets, anemia and other deficiencies, and that a failing appetite in these conditions plainly indicates the need for a brief fast. It should also not be overlooked that in all deficiencies there are toxic states that must be overcome before the best of diets can do its perfect work. Deficiency is not always due to faulty diet. It may be due to impaired nutritive machinery and function, from a variety of causes. Physiological rest is frequently the first essential to recovery in such cases.
(6) Difficult Breathing: This symptom is sometimes seen in two types of cases; namely, nervous cases and cases of heart impairment. In nervous cases it constitutes no warning of danger. In heart cases, it should cause a careful watching of heart action. Should this show signs of weakening, the fast should be terminated at once.
I have fasted many cases, with nothing but benefit, which would not have been placed on a fast by others who employ this measure. I have continued fasts in cases where others would have discontinued the process, with no development in any case of any of the troubles or evils against which we are so frequently warned.
I have fasted cases for more than twenty days who were advised by Dr. Hazzard not to fast more than five days. I have fasted cases that Dr. Hazzard had previously placed on lemon juice and honey rather than on a fast. Fear of legal consequences, should something go wrong, prevents many advocates of fasting from using it to its greatest advantage.
There are cases in which it is well to proceed cautiously and in which the inexperienced person should not attempt to conduct a fast; but in general there is seldom any such thing as a contra-indication to fasting, just as there is seldom or never a contra-indication to any other form of rest.