Haha funny example PTR - but I don't think its an example of NLP. It's more like an example of positive thinking.
And NLP example of that situation would be the fat guy wants to lose weight and he model's himself after someone who has lost weight. Of course he would probably fail as everyone's metabolism and physiology is different.
It seems modeling another person is the essence of NLP - and I think that generally doesn't work. Thats not to say that some NLP techniques like reframing a negative situation in a positive light doesn't work. But even reframing can be dangerous. If you're losing money trading for example and you try to reframe it positively by saying 'oh I'm just paying my tuition' - well then you just continue to go on doing the same thing and getting the same results. I don't think reframing obesity into a something funny or positive is a very healthy thing either.