My advice to you is
1 First of all, we should convince her of the dangers of obesity. Fat people can't buy good clothes to pull, which makes them ugly, and even encourages her to say that she wants to get married in the future. My parents will not like it when they see it.
If you can't move her, you should pay more attention to her diet, keep an eye on her three meals, give her more vegetables and buy her less candy.
You should take the initiative to care about her, so that it will be effective.