Side-effects from fasting are rarely serious, but fasting may uncover pathology and reveal weaknesses that were previously subclinical. Discomfort during fasting may be due to withdrawal from stimulants, hypoglycemia, acidosis, elimination of wastes, and enhancement of repair. Patients may experience headaches, insomnia, skin irritations, dizziness, nausea, coated tongue, body odor, aching limbs, palpitations, mucous discharge, and visual and hearing disturbances. Hair growth is usually arrested, and dry, scaly skin may develop. Most signs and symptoms are usually brief as the body works to remove the disease.
In certain cases, complications occur which may necessitate breaking the fast early. Examples of such conditions include:
• a sudden drop in blood pressure (possibly due to peripheral circulatory collapse)
Fasting elevates serum uric acid levels and uric acid excretion, and if fluid intake is insufficient, gout or renal stones may be precipitated.
A few studies have discussed the development of Wernicke’s encephalopathy during prolonged fasting, but since this rarely occurs during hygienic fasting, it is difficult to determine whether this is related to methodology. It is important, however, to acknowledge the importance of utilizing B vitamins, especially thiamine, when any fast is broken with i.v. glucose.
The decision to terminate the fast should be based on the complete clinical picture and not on an isolated sign or symptom.
Contraindications to fasting are few, and each case must be judged individually, since no two cases are alike. For example, an inexperienced practitioner may assume that emaciated patients should not fast, while Shelton states:
Extreme emaciation: In such cases a long fast is impossible. A short fast of 1–3 days may be found beneficial, or a series of such short fasts with longer periods of proper feeding intervening may be found advisable.
Contraindications include severe anemia, porphyria, and serious malnutrition. Individuals with a rare fatty acid deficiency of the enzyme medium-chain acyl-CoA dehydrogenase (MCAD) should also avoid fasting.
The fasting of children and pregnant women is controversial. While a short fast is appropriate for the sick child who does not want to eat, fasting a pregnant women may be seriously contraindicated: ketosis in pregnant diabetic women is known to cause fetal damage. Although this is commonly recognized, the fact that this information has come only from research of diabetic women is not as widely known. There appear to be no studies of the effects of non-diabetic ketosis on fetal development. Doctors (e.g. Shelton, Benesh, Sidwha, and Burton) with considerable experience of fasting pregnant women (during all three trimesters) have found no adverse effects with fasts of a few days to 2–3 weeks. Although the fasting of pregnant women appears, according to clinical observation, to be safe, definitive pronouncement cannot be made until careful research is performed (such as a controlled retrospective analysis of existing cases).
Fasts for children and pregnant women should be shorter and meticulously supervised by an experienced doctor. In The science and fine art of fasting, Shelton states: “Few infants require more than 2–3 days of fasting … I have never hesitated to permit a sick infant to fast and I have yet to see one harmed by it.”
Regarding pregnancy he states: “The author would object to a long fast in chronic ‘disease’ during this period. There can, however, be no objection to a short fast … ”
It is well recognized that fasting during lactation is not generally advised, since milk flow is halted and difficult to resume. Although fasting is considered inappropriate in renal insufficiency, the authors have seen patients with 65% renal function return to normal as a result of fasting and dietary management.
With regard to fasting contraindications in general, Burton stated:
I have found few health problems which are absolute contraindications to fasting. In my experience, if the need is evident, the only genuine contraindication is fear. … As for the other conditions often mentioned, e.g. kidney disease, heart impairment, TB, etc., they merely require extreme caution, because of the limits imposed by pathology, but they are not inexorable contraindications.
Supervised fasting as a therapeutic procedure is generally safe and effective. The incidence of death at fasting institutions is low, which is promising, since many of the patients have serious chronic diseases and have exhausted other therapeutic options. Of the hundreds of cases of fasting described in the scientific literature, only seven cases of death have been reported prior to 1985. In all cases, the patients had serious chronic disease prior to fasting, and in five of the seven cases drugs were given to the patients while fasting, while in the other two no description of protocol was provided.
There is no evidence in the scientific literature to suggest that fasting itself can be considered a cause of death. Death during fasting indicates that the remedial efforts of the body have been overpowered by the pathological process. This situation occurs in serious disease, whether eating or fasting. In examining the fallacy of attributing the cause of death to fasting, one researcher in the Lancet wrote:
Fasting short of emaciation is not hazardous, if death results, reasons other than those of the fast should be considered before concluding that all supervised fasts should be discouraged.
Therapeutic fasting is a useful protocol for any doctor interested in studying and promoting the inherent ability of the body to heal itself. This fine art and science is generally a safe, economical, and effective therapy for most patients in disease. Those interested in further study should initially direct their attention to the main historical texts and then to the recent hygienic and scientific literature. The references provide a greater depth of information for the topics discussed in this chapter. Internship with a doctor skilled in therapeutic fasting is strongly advised for those interested in providing safe and effective patient care.
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