Chitosan was something i tried, back in the day... no, i don't think that it helped me lose any more weight that i would have any other way. BUT, you will end up on the toilet and spend a lot of time there. Warning, you may lose weight, but not the kind of weight you want to lose, comprende? If you're worried about fat, just read labels and eat lower fat food. If you are aware about what you're putting in your body, that's way better than popping chitosan pills, who knows what else they put in those things!