This section is from the "Nature Cure: Philosophy and Practice Based on the Unity of Disease and Cure" book, by Henry Lindlahr.
Before, during and after a therapeutic fast, everything must be done to keep elimination active, in order to prevent the reabsorption of the toxins that are being stirred up and liberated.
Fasting involves rapid breaking down of the tissues. This creates great quantities of worn-out cell materials and other morbid substances. Unless these poison-producing accumulations are promptly eliminated, they will be reabsorbed into the system and cause autointoxication.
To prevent this, bowels, kidneys and skin must be kept in active condition. The diet, for several days before and after the fast, should consist largely of uncooked fruits and vegetables and the different methods of natural stimulative treatment to assure proper bowel action should be systematically applied.
During a fast, every bit of vitality must be economized; therefore the passive treatments are to be preferred to active exercise, although a certain amount of exercise (especially walking) daily in the open air accompanied by deep breathing should not be neglected.
While fasting, intestinal evacuation usually ceases, especially where there is a natural tendency to sluggishness of the bowels. Injections [salt and baking soda enemas are best] are therefore in order and during prolonged fasts may be taken every few days.
By prolonged fasts we understand fasts that last from one to four weeks, short fasts being those of one, two or three days' duration.
Moderate drinking is beneficial during a fast as well as at other times; but excessive consumption of water, the so-called flushing of the system, is very injurious. Under ordinary conditions from five to eight glasses of water a day are probably sufficient; the quantity consumed must be regulated by the desire of the patient.
Those who are fasting should mix their drinking water with the juice of acid fruits, preferably lemon, orange or grapefruit. These juices act as eliminators and are fine natural antiseptics.
Never use distilled water, whether during a fast or at any other time. Deprived of its own mineral constituents, distilled water leeches the mineral elements and organic salts out of the tissues of the body and thereby intensifies dysemic [blood deterioration] conditions.
While fasting, the right mental attitude is all-important. Unless you can do it with perfect equanimity, without fear or misgiving, do not fast at all. Destructive mental conditions may more than offset the beneficial effects of the fast.
To recapitulate: Never undertake a prolonged fast unless you have been properly prepared by natural diet and treatment, and never without the guidance of a competent Nature Cure doctor.