Two Bowls Are Not Enough

As a heroine, why is she fat? Even if you are fat, why can't you lose weight? But it doesn't matter, she still has talent, but why can't she use it? ! After finally accepting the reality, where did this man who seemed to have a lot of background come from? (All in all, this is a story about a heroine who is not particularly Mary Sue or even a bit weak, and how she can change her destiny without going against the will?)