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.
Disease is labor, action, struggle--it is often violent action. Rapid heart action, rapid breathing, vomiting, diarrhea, etc., etc., represent increased effort. This uses up energy. It often leaves the patient exhausted at the end of his strenuous effort. It may so completely exhaust him as to end his life. Disease frequently means a greater expenditure of energy than the normal activities of health require, hence the urgent need for conservation of energy in every possible way. So great is the intensity of the effort, so fully are the powers of life concentrated upon the work in hand, there is no energy available with which to carry on the work of digestion. The suspension of digestive secretions, cessation of the rhythmic contractions of the stomach and intestines and the withdrawal of the desire for food are, therefore, compensatory measures, equally with the prostration of the patient, designed to conserve energy on the one hand that it may be available for use on the other.
Dr. Jennings wrote of this conservative measure seen in all acute disease: "The great, extensive, and complicated nutritive apparatus, that requires a large amount of force to convert raw material into living structure, is put at rest, that the forces saved thereby may be transferred to the recuperative machinery within their respective limits, so that there is no call for food, and none should be offered until the crisis is passed, or a point is reached where some nutritive labor can be performed, and there is a natural call for nutriment. * * * And food has no more to do with the production of vitality, than the timber, planks, bolts and canvas for the ships have in supplying ship-carpenters and sailors. In the mass of diseases--such as simple, continued, or remittent fever, scarlet fever, measles, mild bilious fevers--and most of the disorders that are termed febrile, that require a few days to do up their recuperative work in, the proper course of treatment to be pursued, is exceedingly plain and simple. So long as there is no call for nutriment, a cup of cool water is all that is needed for the inner man."--Tree of Life, pp. 186-187.
The urgent demand for increased effort which the presence of toxins occasions is the reason for the increased, even violent effort. But violent effort in one direction requires reduced effort, by way of compensation, in other directions. Fasting by the acutely ill is definitely a compensatory measure and its urgency is in direct proportion to the severity of the symptoms. There remains digestive power in a cold, in pneumonia there is none. By this is meant that the more ill is the patient the greater is the need to refrain from eating. Curious as it may appear at first thought, health and hunger come together.