"The DUFF" is a young adult novel written by Kody Keplinger, published in 2010. The story follows Bianca Piper, a high school senior who discovers she is labeled as the "Designated Ugly Fat Friend" among her more attractive friends. Struggling with her self-image, Bianca navigates the challenges of adolescence, friendship, and romance. The novel explores themes of identity, self-acceptance, and the pressures of social hierarchies in high school. It was adapted into a film in 2015, starring Mae Whitman as Bianca and Robbie Amell as Wesley, further popularizing the story and its messages about beauty and self-worth.