You can model this by saying things like “I don’t like to eat Doritos, they taste good but afterwards they make me feel sludgy and tired. I like eating veggies, they are delicious and make me feel light and fresh after I eat them.”;
This is a good idea. On her birthday last week my daughter got a vegie and fruit tray, which was a good move (with cake and ice cream). I didn't have a lot of junk food around when she was a child but she had older siblings and her dad owned a convenience store so junk was always available. There just comes a time when you don't have control over what your children eat anymore.
There is a lot of tension in that household and it's not good at all. Its a very different environment than my children grew up in. All these things add up to stress and I believe she may eat due to that. I've accepted I don't have control over any of their affairs and my granddaughter is now coming to my house once every 2 weeks so we can hang out together. I can make healthy plans with her and hope she likes them. Thanks for your thoughtful comment.