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.
Pains that seem unbearable without the use of narcotics and anodynes rapidly lessen while one fasts, so that within a short time to a few days the patient is comfortable. Repeatedly have I watched the almost unbearable pains of acute articular rheumatism subside and the patient become comfortable after three or four days of fasting. In the last stages of cancer, when nothing is done for the patient except to dose him with opium, and when pains induced by opium are as great (or greater) as those resulting from the cancer, a fast will restore comfort and permit the patient to die in peace.