Jeez the advice on this thread is awful! Please ignore most of it unless you want more issues.
Your daughter knows she's overweight. She probably knows what healthy and slim looks like and what healthy eating would be.
There's a reason why she's eating junk, punishing won't help, restricting further at home won't help.
I was your DD growing up. My mom would try to put me on diets, we never had any treats at home (even before I was an overweight teen), we'd be allowed junk occasionally but my mom would be very vocal about my weight, her ideas of health, healthy eating etc. Made me run in the opposite direction and spend all my money on sweets.
First of all, all foods fit into a healthy diet. Restricting only gives them more power.
Can you afford to buy her a membership or passes to a class she will genuinely enjoy? Doesn't have to be intense, gentle movement to give her an activity she'd like.
Don't comment on her body, or her food choices. Start addressing the reason - boredom, emotional eating? What do you think is actually going on?
Finally, you need to incorporate more "bad foods" into daily life to stop giving them such a pull!
Ex. oven baked chips. Pizza, but with a side of salad. Ice cream, but serve a normal serving size and add fruit.
Cakes, biscuits, all of that goes also - set some good rules around mealtimes. Eating together, no devices or distractions. Everyone gets a treat plate (ex. 2 biscuits and some fruit).
It took me very long and a painful 10 years of eating disorder struggles to realize that once I allowed myself to eat everything and stopped judging it as good/bad, I no longer want to. There's no point, it will be there tomorrow, I can always have it, and look forward to it as part of a balanced lifestyle.
If you don't handle this right, it might turn into an eating disorder. Speak to a professional if you can.