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.
Under his discussion of "Subjective Impressions" arising during the fast, Benedict says, "It is commonly believed that the withdrawal of food for one or two meals results in dizziness, a feeling of faintness, and at times, in pains in and about the epigastrium." This is not only the common belief, it is also the professional belief. Physicians, even physiologists who should know better, attribute any discomfort that may follow the missing of food, to the lack of food. Benedict shows that, while in some cases some discomfort was noticed, in the majority of cases, no such symptoms were observed. On the contrary, unusual vigor and strength were observed. He says: "The fast of Merlatti, which was said to have continued 50 days, was characterized by extreme discomfort, pain, and sensations of coldness. During the 30-day fast of Jacques, the only marked discomfort noticed was a slight attack of gout which appeared on the sixteenth day. In the numerous fasts of Succi, no marked discomfort was observed. In fact, during his fast at Florence his cheerfulness and apparent good health were the subject of much comment. It should be stated, however, that both Jacques and Succi took small amounts of narcotics from time to time throughout their fasts, though, as Prausnitz has pointed out, this may have been as much to stimulate a popular interest in the concoctions as to dull the sense of any possible pain, except possibly during the early days of the fast. Celli experienced considerable discomfort during the first one and one-half days of his fast, but this suddenly ceased after a movement of the bowels. * * * The records of the subjective impressions of J. A. in the experiments in the Stockholm Laboratory, show that on the first day of the fast he noticed no dizziness. On the second day, while his general condition was good, he observed unusual weakness following a slight muscular exertion. On the third day he was not in a little discomfort when climbing on a short ladder inside the respiration chamber. On the fourth day, the pain in the stomach disappeared and no dizziness was noticed in the experiment on the ladder. On the fifth day the general condition was excellent, and there was no pain or discomfort in the stomach. His strength, too, was greater although he noticed that if he arose suddenly from bed there appeared to be black spots before his eyes. * * * In Prausnitz's opinion, the feeling of discomfort attending hunger is, in many instances, a purely physical condition. * * * It seems, therefore, that from the experiments made in this laboratory, the conclusion can properly be drawn that fasting, per se, produces no marked symptoms of pain or weakness, at least during the first days of inanition."
Two factors must be taken into account in our consideration of this conclusion that fasting produces no marked symptoms of pain or weakness during the first few days of abstinence. One of these is that Benedict's tests were made upon comparatively well individuals and these do not develop pains when fasting; the other is that he says "fasting per se," does not produce symptoms of pain or weakness in the first few days of fasting. Pain or weakness or both may, and often do, arise in the beginning of a fast due to a variety of causes, but not to the fast. That they are not produced by the fast is obvious from the fact that they cease while the fast is still in progress. These will be accounted for as we proceed.