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.
In chronic "disease" digestion is not suspended. In many cases it seems not to be impaired. Appetite may and may not be present. There is not, therefore, the same necessity for fasting in chronic "disease" as in acute "disease." Yet, if the fast is entered into, nature usually signifies her willingness to undergo a long deferred fast, which she has probably repeatedly asked for but did not receive, by cutting off the appetite on the second or third day and perhaps by developing nausea, vomiting and repugnance to food, and by instituting the usual processes of elimination. As this course of action is invariably pursued by nature, we are forced to conclude that she welcomes the proffered opportunity for house cleaning.