Looking for story: from parents' perspective

[jadeprogeny]

Unfortunately I don't remember where I encountered this story or who might have written it.

It's from the parents' perspective - their (late teen? young adult?) daughter returns from some sort of camp, and has gained weight and also picked up terrible eating habits. I remember there being a bit where she was eating a chocolate bar and the parents commented and asked where she got it, and she said it was from winning a contest. They probed further and she admitted it had been a marshmallow-eating contest.