I know this isn't a solution to the problem but do you think if she had a Wii with the Wii Fit disc and a balance board it might motivate her to become more active? I have one and I've just started using it again after a lonnnnnng time. The game is cute! She can do step aerobics, hula hoop, balance games, etc. It might be an incentive to help her become more active. It also has a body measure feature that can track your weight gain/loss. Nothing is discouraging about it, in fact the Mii's (instructors) are very encouraging.
If she already has a game system I think the balance board is around $80.
I hope her parents realize that they control the situation. What they buy at the store is setting the example of what's eaten. Best of luck to Samantha.
