This diet is well regarded in my research as well, and prescribed for people with inflammation problems. It also happens to look like the 1st week or so of any kind of elimination diet / partial fasting. I don't know if they are trying to sell something, but you can get the benefits without buying anything, so they don't seem like quacks to me.
This looks a lot like quackery. A miracle diet that will cure almost all ailments? Sounds too good to be true.
The author encourages parents to disregard Physician advice in favor of a vaguely formulated diet advice and expensive supplements, which the author sells. Also lots of enemas and no MMR vaccines.
in my research I was led here. But not sure on the accuracy but they seem to have methods.