JARED LETO

Gained weight for: Chapter 27Lost weight for: Requiem for a Dream
Leto lived on a diet of ice cream and pizza to balloon 67 pounds for his portrayal of John Lennon’s killer Mark David Chapman in 27 (left). Between that and the 25 pounds he shook off to play a heroin junkie in Requiem (right), the actor has given Christian Bale a run for his money in terms of commitment — though he has yet to score any major awards recognition for his body of work.

JARED LETO

Gained weight for: Chapter 27
Lost weight for: Requiem for a Dream

Leto lived on a diet of ice cream and pizza to balloon 67 pounds for his portrayal of John Lennon’s killer Mark David Chapman in 27 (left). Between that and the 25 pounds he shook off to play a heroin junkie in Requiem (right), the actor has given Christian Bale a run for his money in terms of commitment — though he has yet to score any major awards recognition for his body of work.