As Matt Damon demonstrated this week, sometimes even movie stars sacrifice their typically enviable bodies for the sake of their roles. From gorging on junk food and pizza to logging serious gym hours, these celebrity weight gains take different shapes and forms. Take a break from worrying about the Freshman 15 to check out how these stars did you one better.

Hilary Swank Million Dollar Baby (2004) By the time Hilary Swank finished bulking up for her role as amateur boxer Maggie Fitzgerald, she had put on 19 pounds of muscle and looked like she could knock out most dudes.

Charlize Theron Monster (2003) As serial killer Aileen Wuornos, the usually glamorous Theron gained 30 pounds and a whole lotta ugly. A diet of potato chips and some seriously blotchy skin helped her pull off this transformation.

Matt Damon The Informant! (2009) Damon confessed to enjoying his extra 30 pounds, which he credited to binging on doughnuts and burgers, plus forgoing his usual trips to the gym. His new bod helped him embody the role of lazy Midwestern businessman Mark Whitacre.

George Clooney Syriana (2005) One celebrity who didn’t enjoy packing on the pounds was George Clooney, who gained 35 pounds as CIA agent Bob Barnes. The star confessed that being overweight was uncomfortable, and he subsequently slimmed down for his next role.

Robert De Niro Raging Bull (1980) De Niro did the nearly unthinkable by putting on 60 pounds of pure muscle for his Oscar-winning role as boxer Jake LaMotta. This brawny frame didn’t last long, though, as De Niro presumably grew tired of such long hours in the weight room.