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.
When we observe body temperature during a fast, we are presented with a paradoxical series of phenomena which prove both interesting and highly instructive. For example, temperature tends to remain normal in most cases of fasters suffering with chronic disease, to fall in acute disease and to rise in those patients who have sub-normal temperature. Benedict points out that during the fast, for a period of seven days at least, there is an occasional tendency for it to increase as the fast progresses.
Temperature does not rise as high in fever patients who are not fed as it does in the same patients when fed. Invariably, the temperature falls to normal as the fast progresses. Indeed, in acute "disease," where there is high temperature, the fever subsides somewhat as soon as eating is discontinued and seldom rises high thereafter.
In rare cases of chronic disease there is sub-normal temperature. This is most likely to be observed in the morning before the patient has become active. It is striking evidence of the value of the fast that in these patients, as the fast nears its natural termination, the temperature rises to normal and remains there. In those chronic sufferers whose temperature is habitually below normal, it will surely but slowly rise until it reaches normal by the time the fast naturally ends. "Thus," says Carrington, "supposing the patient's temperature to be 93.8° at the commencement of the fast, it will gradually rise until about 98.4° is reached--though the fast may have extended over forty or more days. . . . Time after time, in case after case, I have watched this gradual rise in the bodily temperature of the patient, and in every case the temperature has not failed to rise as the fast progressed. At first, it is true, the temperature sometimes tends to fall, but let the fast be persisted in, and a return or rise to normal will occur in every case."
Carrington records several cases where temperature was subnormal while eating, but gradually returned to normal while fasting. In some of these, premature eating resulted in an immediate drop in temperature. One case he records had a temperature below 94° F. before the fast. At the end of a thirty-four days fast the temperature had nearly reached the normal standard.
A. Rabagliatti, M.A., M.D., F.R.C.S., Edinburgh, made this same discovery, and says of it, "In point of fact, I raised the temperature of a man who was, besides thin, emaciated, and attenuated by constant vomiting, lasting for seven years, from 96° F. to 98.4° F. by advising him to fast for thirty-five days. On the 28th day his temperature had risen to normal, and remained so."--Air, Food and Exercise, p. 261.
Low temperature is often the result of too much food, or lowered vitality due to habitual over-eating The case just quoted from Dr. Rabagliatti was, as he remarks, "dying on the plan of frequent feeding." He lost 13 pounds during the fast and gained health although he had been sick and taking a "highly nourishing diet" for seven years. Carrington noted a few instances of long fasts where the temperature dropped a degree or two immediately upon resuming eating.
Dr. Hazzard records a case in which body temperature was constantly at ninety-four degrees at the beginning of the fast. No change in temperature was noted until the twentieth day, when it increased nearly a degree, it reached ninety-seven degrees ten days later and remained at this standard thereafter. She also says that in a few subjects the temperature was so low that it could not be determined on a clinical thermometer, but "invariably normal individual average was reached before the end of the treatment."
Experiments upon starving animals show that the temperature remains normal through the fasting period and then begins to fall rapidly for from 2 to 6 days before death supervenes.
It is the rule, in chronic troubles, for the temperature to remain normal. Dr. Eales' temperature remained normal throughout his fast. Dr. Tanner's temperature dropped at the end of his fast, although he survived. This drop in temperature, both in man and in animals, undoubtedly marks the exhaustion of the body's reserve resources and the beginning of actual starvation.
I have had but one such case in my own experience, the sudden drop occurring on the 36th day of the fast. I broke the fast immediately and kept the patient warm with heat applied externally. He made a quick recovery and suffered no ill effects.
Carrington thinks that the fact that temperature falls to normal when above it and rises to normal when below it and that it reaches the normal point, in either case, just as the fast is completed and ready to be broken, is further proof that "fasting is a natural process, counselled by nature, with landmarks clearly defined, and but waiting to be recognized by man." This, it seems to me, is the only logical conclusion that can be drawn from the facts.