The weak link she seems to think she sees in that chain is "I look gross because I am fat."  This sort of person, I guess, thinks that maybe the brain can be trained to disbelieve that.  Which it surely can, somehow.  Maybe water torture or lobotomy would be involved, or maybe somebody can just convince themselves.  But I expect it can be done. But personally I feel like it would be easier to just eat less than to try to remake a chunk of my personality like that...  god that seems so tricky, and so unreliable.  Even if you got it to work, your brain could still rebel at any time; you don't know what's going on in there.  Your confidence in your fat body could fall apart one day because you became temporarily depressed for some unrelated reason.  Whereas if you just roll with your own aesthetic preference and become physically fit, then you're safe!  Your body won't plump up again suddenly.  You have control!  Plus all the other huge benefits of being fit.