I disagree with not raising it. I was an overweight teen - actually roughly the same weight / height as your dd in fact. My mum was very open with me about weight - it helped that she was overweight too and she took the approach of "let's tackle this together". We went on lots of walks together, she stopped buying snacks/junk food and cooked lots of delicious homemade meals that were healthy and full of veg. She never told me not to eat stuff or restricted choice but she would always say "yes you can have a chocolate but maybe some exercise this afternoon then?" or "OK you can have seconds if you're hungry but are you sure you are? You've eaten x,y and z today which should be enough". Just ways to prompt me not to eat mindlessly. I lost lots of weight and ended at 8 stone where I stayed for most of my life until now where I'm 11 stone again after having a baby. Anyway, my point is, I found honest and open communication so helpful. Also she was very careful never to use words like "greedy", "lazy", "fat", "ugly" - she would always sympathise and agree that chocolates and ice cream are delicious and it would be lovely to eat them everyday but we must look after our bodies and nourish them with good food too! She'd also agree that it's hard to motivate yourself to exercise so she always looked for activities I would enjoy - as I say, walking to school / town as part of our normal routine and then bike rides / aerobics to pop music / yoga and pilates / Zumba when I was a bit older and it was just becoming a "thing". It did take a while to shift the weight because I didn't crash diet or do something faddy (and no weight doesn't "fall off easily" when you're overweight as pp have said - that's usually why you're carrying the extra pounds in the first place!) but I did it in a sustainable and manageable way.