This section is from the "Nature Cure: Philosophy and Practice Based on the Unity of Disease and Cure" book, by Henry Lindlahr.
Next in importance to building up the blood on a natural basis is the elimination of waste, morbid matter and poisons from the system. This depends to a large extent upon the right (natural) diet; but it must be promoted by the different methods of eliminative treatment: fasting, hydrotherapy, massage, physical exercise, air- and sunbaths and, in the way of medicinal treatment, by homeopathic, herb and vitochemical remedies.
Foremost among the methods of purification stands fasting, which of late years has become quite popular and is regarded by many people as a panacea for all human ailments. However, it is a two-edged sword. According to circumstances, it may do a great deal of good or a great deal of harm.
Kuhne, the German pioneer of Nature Cure, claimed that "disease is a unit," that it consists in the accumulation of waste and morbid matter in the system. Since his time, many "naturists" claim that fasting offers the best and quickest means for eliminating systemic poisons and other encumbrances.
To "fast it out" seems simple and plausible, but it does not always prove to be successful in practice. Fasting enthusiasts forget that the elimination of waste and morbid matter from the system is more of a chemical than a mechanical process. They also overlook the fact that in many cases lowered vitality and weakened powers of resistance precede and make possible the accumulation of morbid matter in the organism.
If the encumbrances consist merely of superfluous flesh and fat or of accumulated waste materials, fasting may be sufficient to break up the accumulations and to eliminate the impurities that are clogging blood and tissues.
If, however, the disease has its origin in other than mechanical causes, or if it is due to a weakened, negative constitution and lowered powers of resistance, fasting may aggravate the abnormal conditions instead of improving them.
We hear frequently of long fasts, extending over days and weeks, undertaken recklessly without the prescription and guidance of a competent medical adviser, without proper preparation of the system and the right subsequent treatment. Many a good constitution has thus been permanently injured and wrecked.