How to Diet as a Lady
This comic includes surprisingly little fatshaming, and when there is some it's in a teasing manner or from characters meant to be antagonists. In the first few chapters, the FL is indeed notably shocked by her appearance and says some cruel things about herself but this sentiment stops pretty much immediately after the first reveal. The ML has zero problems with her appearance, he finds her quite attractive in fact. We also find out he's helping her lose weight because that is her wish and not because he thinks it's what she should do. The most problematic are the FL's brother and some minor Antagonists. The brother calls her a pig but to me at least this came off as teasing, the same way you may compare a sibling to Yoda or Gollum. The minor antagonists do fatshame her but they're clearly portrayed as having stepped out of line and being wrong with their actions. Nonetheless, the FL names them as her reason to lose weight - she says she felt insecure when they berated her and wishes to become more confident (by molding her body herself, a form of retaking control after her reincarnation I assume) All in all quite a nice surprise!! And very funny!
Seijo no Maryoku wa Bannou desu