Your granddaughter already gotten a taste of the drug, and she’s not mature enough yet to understand what it’s going to do to her. My advice would be to teach her to cook: teach her to make a few dishes that are healthy and delicious. There will be a point when she is older that she will want to take control of her eating and not let it control her, and at that time, she will be much better set up for success if she knows the basics of cooking for herself. People who don’t cook often can’t conceive of even how to do it, and they literally buy fast food or takeout to eat every night. You could be that difference in her life now, and you don’t even have to express judgment about the way she currently eats, just tell her grandma wants to show you how to cook a few of her favorite meals