Hi,
Your daughter is in growing age, so at this phase nothing should be comprised. Though her weight is more, but still, compromising of calorie intake can't be done, but yes you can indulge herself to do more activity which is quite natural in her age. You have already identified the main cause behind her gaining weight, means to avoid junk food. In her age, many children get used to it, because of the taste and looks of the junk food. Gradually by proper counseling you need to correct this habit, don't force her, rather first you minimise the frequency and quantity, then slowly remove it. Decorate the homemade food in such a way that it looks attractive, make her believe that this is also tasty one. Make a menu planning for week where one menu shouldn't be repeated more than twice and not for consecutive days.
Health Tips
Please don't impose anything forcefully to her, which can make situation worse.