I was using it to mean "arbitrarily much food". My position is similar: If you eat just until you're full and you get moderate exercise but you're still overweight, you should talk to your doctor. You may still need to change your eating or exercising habits, but you should do research first, and not make any sweeping changes all at once.

Changing your habits is always difficult, and that's where the willpower comes in. It should only be needed until you settle into your new habits, though. And you should never have to be constantly hungry, or end up having to eat almost nothing, as Janet said. Both outcomes are extremely unhealthy.

I think I'll add this to my original post to clarify my position. I seem to have come across as more extreme than I intended.