I've also read that tea - especially green tea - acts as a sort of natural starch-blocker. (That was in one of Fran McCullough's books.) That might also be part of the puzzle.

And the relative absence of the kind of chemical junk that makes up so much of the SAD might also have something to do with it. I've always thought that it's not just the carbs -- it's also what we do to them that causes the problem.