I'm not sure but I think it has something to do with snacking on cheese, eating lots of pasta (with cheese), drinking probably too much milk and not eating enough vegetables. I don't keep snack foods in the house unless you want to count triscuits and other crackers. Another problem is lack of exercise.
If your daughter likes pasta, then serve 100% whole wheat pasta with plenty of a veggie-packed marinara sauce and a sprinkling of a good fresh parmesan. The fresh cheese has a much more robust flavor than
Get rid of anything "starchy" that isn't 100% whole wheat - read labels! No potatoes, no white bread, no white flour. Triscuits are a nice snack and relatively low in fat and calories with a lot of fiber. Fiber is filling! Have her try taking a fiber supplement about 20 minutes before eating a meal, and she may find she gets fuller on less food.
Instead of red meat serve plenty of fish and chicken. Beans and eggs are a good (cheap!) source of lower fat protein. Also low fat dairy usually tastes better than fat free and generally has similar calorie counts and less fillers.
I have a mini trampoline that I bought about a year ago. I actually have some trampoline workout DVDs that are gathering dust on the shelf (the Urban Rebounding series). It can be a good cardio workout and helps build leg muscles too. Just have your daughter start SLOW - maybe 10-15 minutes of vigorous bouncing will be enough to work up a sweat and raise the heart rate without cauing too much muscle soreness.