My First Love Is Secret Love (2021)

Also set in 2008, Go, Back Diary is about high schoolers experiencing their first love. Webdrama is short but has a lot of developements packed in just 4 episodes. We are also told what happened to the characters in present time.

Another drama partially set in the past, tha has you guessing what happened to the characters and what led them to their present life.
Reply 1997 and My First Love Is Secret Love are both heavy on nostalgia, abeit they start 11 years apart.

Both female leads have crush on the male lead in high school. both of them are fat at first and then they transform to slim.
Both DRAMAS are the FEMALE LEAD ugly duckling and fat and then she becomes beautiful girl and slim.

I really its so similar to drma if u liked it