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.
"This is but one instance of many that have impressed the value of fasting where to some practitioners it might have been contra-indicated. If the body, because of its crowded nutrition, cannot assimilate vitamin bearing food, it can be brought into condition to do this by a purifying fast."--In Defense of Rational Fasting.
Another objection offered to fasting is purely theoretical and is based on the reigning theories in biochemistry. That these theories are correct has not been shown and there are serious objections to them. At any rate, the developments we should expect if these objections are valid, do not show up during the fast. The objection is this: "All the energy of our bodies comes from either fat or glucose. In order to produce energy all other foods must be changed into fat or glucose, one or the other. But here is the important fact; when blood-sugar or glucose is burned alone, by itself, energy is produced with maximum efficiency. But when fat is burned alone, it is burned incompletely, and yields as by-products acetone and harmful acids, which accumulate more and more as long as fat continues to be burned without sugar. This is what happens when a person attempts to 'fast,' that is, tries to go without food."
If this objection is valid, it would certainly be impossible for us ever to observe gains in strength and energy in fasting patients. Either this objection is wrong, or else all who have seen gains in strength in fasters have been seeing the same kind of things seen by the drunk watching "pink elephants" on the wall.
We refute this objection, not alone on the grounds of experience, but also upon theoretical grounds. First, there is no rapid exhaustion of the body's sugar reserve as this objection implies, when a fast is undergone; second, the fasting body produces a daily supply of glycogen from its stored reserves. The physiologists, Zoethout and Tuttle, say "during starvation (fasting) the blood sugar falls but little below the normal level (although it is being constantly consumed) and the liver still contains some glycogen; this is due to glyconeogenesis."--Textbook of Physiology. Glyconeogenesis is the term applied to the formation of sugar in the animal body out of materials other than carbohydrates. Amino acids, after these have been de-aminized, may be transformed into sugar. This is to say that the portion of the amino acid that is left after the amines have been split off may be transformed into sugar. Glycerol, formed by the digestion of fat, may also be converted into glycogen. Apparently the fatty acids--palmitic, stearic, butyric, etc.--cannot be made into sugar.
What, then, becomes of those acetone bodies about which we hear so much? That they do show up in a fast is not denied. But we have a different explanation for them. One of the surest signs that the fast is nearing its end is the disappearance of acetone from the breath, urine and excreta. The presence of acetone is part of the ketosis that fasting is said, in some quarters, to produce.
Ketosis is the presence in the blood of certain end-products of fat-metabolism, known as ketones. There are three ketones--acetone, aceto-acetic and beta-oxybutyric acid. The presence of these bodies in the blood is said to produce acidosis and damage the body. The damages that these ketones produce are never described and those who have had most experience with fasting have never seen them. It would be interesting to see a catalogue of the evils that flow from the presence of these bodies. Dr. Gian-Cursio, who says he has never seen any evidence of harm from the presence of these bodies, and who thinks of them as evidences of normal adjustment to the fasting state, says that "their absence would be cause for alarm."
These same bodies are present in certain stages of diabetes and from this fact, it is reasoned that they are harmful. It is the rule that when there is ketosis, the blood is slightly alkaline so that the acidosis that is imagined is not actually present. It is even denied that diabetic ketosis is the same as fasting ketosis. We are certain of one thing; namely, that the diabetic faster is able to oxydize sugar. Benjamin Harrow, Ph.D., professor of chemistry, City College, College of the City of New York, says: "The fact that in starvation and diabetes, acetone bodies accumulate in an appreciable degree has led to the view that they are abnormal metabolic products. This view must be revised, for the evidence is accumulating that these substances are indeed normal metabolic products." Thus the more advanced physiologists and bio-chemists do not regard the older theory as any longer tenable.
It is claimed that the sick must eat to "keep up their strength," that food cures "disease," and that it increases resistance to "disease." If food cures the sick, how did they become sick? If feeding increases resistance to "disease," how do the well-fed fall ill? If fasting lowers resistance, how do so many fasters recover health? If food builds strength, how do the well-fed grow weak? If fasting, per se, robs the faster of his strength, how do so many fasters grow stronger? If food is essential to recovery, how do fasting patients ever recover? Why do not all fasting patients die? Why do they have more comfortable and less protracted illnesses and shorter convalescences? Why do they recover without complications and sequels? If people who are taxed to death by excess food become sick, how will more feeding help them? Why does feeding make them worse? Why does temperature run up and discomfort grow more pronounced after eating? What are the diseases that are caused by fasting? Will somebody please give us a catalogue of them? Dr. Shew declared that abstinence does not cause disease, that even the person who dies from starvation dies from debility rather than from disease.
A patient in a sanatorium with which I was connected a few years ago was too weak to walk up the steps at the time he entered the institution. He was placed upon a fast and did not taste food of any kind for eighteen days. Before this time was up he was able to run up the steps. If food gives strength why was he so weak while eating and why did he gain strength when he ceased to eat? I had one patient who was too weak to walk up the steps at the beginning of a fast, but was forced to crawl up the steps. After a week of fasting, he was able to walk up the same steps.
Food is not nutrition. Overeating with continued wasting of the body is an every day experience of life. Reduced eating with gain in weight and health is becoming a more common experience as people learn that gluttonous indulgence is not conducive to health of body and clearness of mind. The most important element in nutrition is the living, active body that utilizes the food, and not the dead, passive food that is utilized. When the body is not in a condition to carry on the processes of nutrition, it is worse than idle waste to feed it. Such a patient should fast.