Nira

Niro was a little insecure about his weight, until some milk accepted from a strange man changed him into Nira. She is the protagonist of Overweight.

In Overweight
Niro lived alone. At a supermarket one day, a mysterious individual came up to him and gave him a carton of milk, claiming it would make him look good. Despite the guy clearly being a weirdo, Niro took the milk home. After having a shower the next day, he came upon the milk in the fridge. He drank it in one go, and soon found himself changed into a beautiful woman named Nira. Happy with her new look, she decided to keep the carton as a memento.