She can, but it wouldn't be healthy. It would also be hard. But, to make things easy, maybe you can....

1. List her activities and what she eats on mypyramid.gov. Click Tracker on the left hand side and make an account. easy!
2. She can eat, then maybe run with you in the local track.
3. After school activities?

Give her positive feedback. "Your not fat, but if you think you are, you can come with me to the gym."

Also, dont make her stop eating. That has nothing to do with it. People get serious problems if they stop eating. If people think they are fat, its mainly with their head. They might get depressed, or tired, and, may I repeat, NOT THE WAY TO GO!!

Hope that helps,

Mysteryluna