3-Kellan Lutz, Actor

Kellan Lutz understands the power of a six-pack. His abs epiphany came during an eighth-grade graduation party at a water park. "Before then, I never knew abs were attractive," says the 26-year-old, who plays vampire Emmet Cullen in the Twilight films. "Where I grew up in Arizona, you would never see anyone without a shirt on at school. But when I took off my shirt, all the girls were, like, 'Oh, look at your abs!' And I was, like, 'Yeah!'" Psychologists call this "positive reinforcement." And Lutz instinctively knew what to do: Stay active. 

12-Taylor Lautner, Actor

It may not look like it now, but Taylor Lautner isn't a naturally strong guy. He became that way out of necessity. After all, between the first and second Twilight films, his character grew into a powerful werewolf. That meant he needed to gain 30 pounds of muscle in a year. Which he did, transforming his 5'10", 140-pound, teenage frame into a ripped fitness animal. You might say that going from scrawny to brawny was simply a brilliant career move. But he isn’t done yet: "My character continues to grow," says Lautner, who’ll step back into the role of Jacob in Breaking Dawn this fall, "so I'd like to pack on at least a few more lean pounds." 

Men's Health

via : Twilightish