Actually, the whole idea behind OA and most 12 steps is that your addiction is not wholly your fault, and you need to turn to a power greater than yourself in order to overcome it. It takes an unbelievable amount of humility to do something like that, and that is what Chantal lacks. There's a big difference between using your addiction as an excuse, which is what she does, and being honest about the fact that you cannot control your addiction and are being controlled by it.
She would benefit SO greatly from a 12 step program, because she exhibits so many of the classic addict attitudes. Same with AL. But neither will, because they know what they're doing, guise, and the fact that they are 400 and 500 lbs respectively proves that they are true weight loss gurus.