The Duff treads a recognisable path but peppers regular doses of charm and humour along the way. Bianca (Mae Whitman) leads a fairly content high school life, until she discovers she’s the ‘duff’ (Designated Ugly Fat Friend) to her two best friends. In need of a reinvention, she enlists the help of pretty boy Wesley (Robbie Amell). Josh A. Cagan’s script pursues the common formula of teen comedies, with the twists and turns evident from a mile-off. But then, as familiar as it all is, the characters are well formed and performances full of pep (Whitman is perfectly cast as the outsider in need of clarity, while Amell and Allison Janney as Bianca’s motivational speaker mother add nice support). The dialogue, too, crackles with wit, standing to the defence of people who don’t conform to social norms. It may not do for the teen films what Mean Girls or Easy A did, but The Duff does well enough on its own merits to engage and entertain on a moderate level.