Fat people love seeing other fatties succeed. This is why shows like The Biggest Loser drew a decent (hefty) sized audience.
This show will have alot of fatties fail; most of the fatness will be sent home by the end of the season. While this failure of fatness might provide some novelty viewing pleasure, ultimately it will get old. I give it two seasons, tops.
Sidenote: If you <3 the fatness check out Dance Your Ass Off. You're welcome