I’ve found more manga that has a female weight gain.
First is KaruCan!
https://mangaraid.com/manga/22507.html
And the second one is Eiyuu Kyoshitsu that has a female weight gain is chapter 4.
https://mangakakalot.com/chapter/eiy...su/chapter_4.2
And feel free to post more manga, manhua, or manhua that has a female weight gain.