Wiggs...you really believe Mentzer?
He was a very good marketer, as crazy as he was. His mail order business, at its peak, was a 7-figure business and far eclipsed Arnold's at the time. He was the master at pushing iconoclastic ideas (at the time) in an effort to differentiate his books/manuals/mail-order-business/persona.
Are you sure he really believed this? Or was he just peddling his scheme to sell a few more newsletters to would be bb'ers?
Take it with a grain of salt.
PS: I don't think he's wrong, per se. I've dieted on foods like that too. But I really doubt he got into contest condition eating that way. No one did that in those days, and there's no way he'd do it in real life just to be different.