she'll be fine. she probably will either lose the weight then gain it right back, or she won't lose it at all.
thats kind of stupid of your parents though. they shouldn't give her rewards for losing weight, they should just watch her eating. i mean, she's young, in their house, they should make healthier foods and not buy crap.
but thats just me, and i shouldn't talk b/c all i eat is crap. but then again, i'm 115 lbs.