Absolutely in rodents, and some case studies and anecdotal evidence in humans. But we still need some larger controlled intervention studies. Or barring that, enough of Dr. Colin Champ's patients doing better than expected on the ketogenic diet. Sometimes things are obvious without double-blinded studies--like when Dr. Bernstein originally gave himself perfect blood glucose using the feedback from a home glucose monitor.

Personally, I think this whole thing will be borne out, and if the studies are allowed to be done, a protective effect will be found. But I say think, not know.