Weird relationship with food

C
Ok, so I'm not sure if this is controversial or not, but I have a 9 year old step daughter and her father and I are worried about her relationship with food. Ever since I've known her (3 years), we have had to watch her at parties or whenever there is junky or tasty food around because she will literally make herself sick overeating so much. We have talked to her about her so many times, tried giving her tips and reminded her to listen to her belly so she doesn't overdo it, but she just can't seem to control herself. We have to forbid her from eating more sometimes, and she gets so upset with us. We will eat before going to parties so that doesn't show up hungry and that doesn't seem to matter. She just loves to eat. I once asked her if she was still hungry and she couldn't as set me... She doesn't actually know if she's hungry sometimes. 
We are pretty strict in our house- no junk at all, and we have had to restrict access to bread because she will eat that all day long. Her eyes are always looking for food, looking for the bigger portion. 
And now that she's 9, she's starting to get a little pudgy. She's become lazier than she ever was too. We are very careful never to say anything like that to her, because I'm afraid that this wierd relationship with food will turn into the other extreme one day as body image issues become ever more present in her life.
Anyone ever deal with something like this? The rest of us are really not like that- we eat when we are hungry and we stop when we are full. Is this normal??
I'd like to emphasize that we in no way restrict healthy foods. She can eat as much for dinner as she wants, but she can't eat bread for a whole day or a bowl of rice for supper.  We even allow for treats, but we don't allow for processed foods, like store bought cookies, ice cream, etc. Because we don't believe it is healthy.