I am always surprised by medical professionals who ought to know better when they say that fasting (or a juice fast like the Master Cleanse) is dangerous, will cause heart trouble, will cause death, etc. They obviously haven’t ever tried the Master Cleanse or other fasts, or even read Fasting – and Eating – for Health by Joel Fuhrman, MD; Fasting: the Ultimate Diet by Alan Cott, MD; The Science and Fine Art of Fasting by Herbert Shelton; or Diet Wise by Keith Scott-Mumby, MD, PhD.
The evidence for the power of fasting has been in the medical literature for decades. In Alan Cott’s book above, he has 329 citations. 158 of which are in scientific journals. He even quotes the New England Journal of Medicine.
Cott himself was a psychiatrist, who was introduced in 1970 to fasting to handle schizophrenia and other mental illnesses by Dr. Yuri Nicolayev of the Moscow Psychiatric Institutes Fasting Unit. Dr. Nikolayev was the first to put forward the idea that schizophrenia was caused by a biochemical imbalance and could be cured with fasting and diet.
According to Dr. Cott, Dr. Nikolayev used fasting on patients who did not respond to any other treatment. Seventy percent (70%) of the 10,000 patients fasted recovered and resumed an active life. Based on what he learned, Dr. Cott instituted a 25-day fasting cure at New York’s Gracie Square Hospital.
In his book, Dr. Cott makes the point that fasting itself does not cure. Fasting enables the body to exert its amazing powers of recuperation.
What other diseases respond to fasting? To answer that question, I offer this list compiled from the 2001 Conference on Fasting Therapy for Internal Pathology in Russia:
general health improvement
high blood pressure
cardiovascular disease
nodules in lung, liver, lymph
bacterial & viral Infections in the:

gall bladder