For example, go out for a walk after dinner, or you want her to chat with you and discuss problems. If your sister doesn't realize that she wants to lose weight and is confident, all you have to do is support her, or take her to eat healthier food, which is good for losing weight. Find something that is taboo for obesity and remind her that it is not delicious and bad for her health. If she insists on eating it, tell her angrily with coquetry eyes. Everyone can't refuse to care about her words.