I think some of the comments made in the thread about Sam's weight are unduly harsh in that they don't give him enough credit. I'm not in disagreement that his weight was a major factor in why he won, just that it wasn't the only reason why we won. A positive mental attitude and a willingness to endure suffering are also a big part of why anyone wins on this show, and Sam has both traits in spades.
Throughout the entire run of the series there have been plenty of other obese or heavy-set contestants that didn't last nearly as long as Sam in either of his seasons, tapping because they were terrified of the animals, or missing home, or couldn't endure the solitude for a day longer, or because of the misery of being exposed to the elements or being without adequate food for days on end. A lot of the more fit contestants also tapped because they had reached a mental breaking point.