This clinic has researchers and they publish, plus they cure the incurable, it's not something to be dismissed as a "fad". If anything, the fad diet is whatever we're doing since the 50s, or all the way up to the invention of agriculture.

Your argument supposes you know something that the experts in the field don't know, since there is no consensus supporting such a diet.

The increased animal suffering alone is a good reason to not try such a diet, nevermind the small support in the scientific community.

I think I do, I'm in remission from chronic autoimmune disease thanks to this diet.

The clinic publishes research, that it's not mainstream doesn't in any way invalidate their results.