Jacob's body is definately not fake! aka Taylor Lautner is a very athletic young man, who had training in martial arts and I beleive while filming New Moon did some extra training of some type to "bulk Up" for his transformation from boy to man/wolf as did the others in the cast who were in the pack.
Personaly, I admire Jacob not just for his body but for being the young man that he is. Edward, he is attractive in a different way, both young men very good looking but I must admit my favorite is Jacob.
I agree that Edwards body is more attractive to me than Jacob's body but that is just my preference. I am not big on huge muscles and definition tone. I like a more natural looking men. The big turn off about Jacob to me is his attitude in the book. Movie wasn't as bad but either way, if a girl says she is not interested you should not continue to pursue her. Big turn off for me.
Back to bodies though, Edward sparkles and I love things that shine. :D