Character: Thor, the Norse god of thunder Weight change: Hemsworth gained 20 pounds of muscle for the role. Method: Hemsworth revealed that he had never lifted weights before preparing for "Thor." With a trainer, the actor utilized workouts that varied weight and reps to build dense muscle mass. Come production time Hemsworth was actually too big for his costume, and he had to burn calories until he fit. There's more: The actor looked noticeably slimmer at the "Thor: The Dark World" premiere (sequel to "Thor"). He told Jimmy Kimmel that he's limited to 500 calories a day as he gets thin to play a stranded sailor in "In the Heart of the Sea." That equates to a few small salads throughout the day and going to bed hungry.
Zade Rosenthal / Marvel Studios