Dr Fuhrman MD was an internee of Sheltons and learnt his trade from him, after becoming his patient with a foot injury from his ice-skating career, and because of his influence and success with Sheltons recommended healing protocol changed career, so most things he knows about fasting are from that origin.
Dr Shelton is attributed with singlehandedly reviving Natural Hygiene or Orthopathy (as he later came to call it) from the pioneers of health care dating back to the mid 1800's from Dr Isaac Jennings MD, Dr Russell Thacker Trall MD, Felix Oswald MD, Charles E Page MD, Susanna Way Dodds MD and many many others, who became disillusioned with allopathic medicine and the drug-cure mentality, and had much greater success with the elements of Nature including fasting.