I remember an article on the NY Times with a title saying something like... "One hamburger can ruin a month's worth of dieting"
But, their whole thing was that, once you ate it, or other junk food, the resulting insulin spike would cause you to be hungry/crave again. And, then the cycle starts. A slippery slope if you ask me.
It sounds similar to what Art is saying, just not so much savvy jargon. I think both dont take into mind that some of us are disciplined and can work through pain and a little hunger...
Besides, if either were true, then how could anyone diet? I mean, didnt we all used to eat all that junk? I know I used to eat it every meal, am I lost forever?