I never eat more than half of what is on my plate and throw the other half out. It's also the reason I don't have food issues and I'm not fat.
In the words of Inigo Montoya: I do not think that means what you think it means.
I can honestly say I've never looked at a half-full plate and thought, "Well, that's enough for me. Guess the rest of this tastiness can just go in the trash. Lord knows, I wouldn't want to just cram it all in there and get fat because I haven't tainted it with other refuse!"
I have no idea why this person thinks this isn't disordered eating, or if s/he really believes that the only difference between her/himself and a fatty is the fact that s/he wastes half of all food s/he encounters. I wonder what the reaction to such a statement would have been if s/he had posted on a forum with looser rules than the one where I read this: would anyone have said, flat-out, "That IS a food issue"? Would anyone have agreed with such a notion? Would it have devolved into a flame war against wastefulness?
What would you say to this person?