Wannabeskinny, I personally believe that it's essential to turn to scientific research to understand
how a diet affects the body and
why (but then again, as a scientist I'm quite biased
). The problem with relying on our own intuition or common sense is that... it's often wrong. I should mention, though, in this case your theory is a pretty darn good one, and is consistent with much of the scholarship that has focused on this issue!