Seems like quackery to me. Anything that purportedly cures everything,
cures nothing.
I agree that no one thing can cure everything, but I also know that
doctors are trained to treat syptoms rather than find the underlying
cause of the problem. I also agree that the vast majority of chronic
"illnesses" are really just the body's attempt to cope with something
you're doing to poison it. Auto-immune diseases, for example, are
caused by an allergy to something you are eating or surrounded by.
Figure out what that substance is (it's most often wheat) and avoid
it, and you won't have to take drugs which can cause lymphoma, among
other deadly "side effects". All the doctors want to do, however, is
write scripts, because that's all they know how to do. It's not like
they get anything more than a cursory training in nutrition.