Mouser

Hi, I need help. My 7 year old is overweight. We are very active, however, she is in the 10th percentile for hight. We eat healthy at home, but when she goes to her dads (he is a good dad so don't get me wrong), well him and his girlfriend (who I also like) doesn't feed them that great. They don't have a lot of money to buy heath food, so they get a lot of corn dogs and such. I have talked to him about this before, but I understand with 4 kids (he has two) they can't spend that kind of money. I have tried to send food with, but she feels odd when she is eating something different then they are. I don't know what else to do. They get candy only on holidays and we don't have sugar in the house. It makes me said to see her like this. I don't say anything bad to her about it, but she will sit and talk to me. it's hard to listen to my 7 year old feel the way she does. She has lots of friends at school, but some tease her.
Do you have any advise.