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.
Weakness in acute "disease" is not properly attributed to the fast. Indeed, the fasting patient will not become as weak as the eating patient. He is more likely to grow stronger as the fast progresses. I am pleased to present the following orthodox testimony, on this point, by Dr. Liek, who says: "Those who are sick feel weak. Those who have been operated upon and who wake up from the narcosis are greatly enfeebled. According to the text books, we can overcome that weakness with strengthening food. Nothing is more obvious. Hence, we inquire for the most nourishing and strengthening foods and give them to patients. That idea is, of course, completely mistaken. The patient has been weakened not by a short fast, but by the disease, by the after-effects of the narcosis, the shock of the operation, etc." It should be obvious that the weaker the patient is, the less able is he to take and digest nourishment. The weaker he is the greater is the need for rest.