media_removed_toofab 102011

Alexander Ludwig
plays the massive, bad boy Career Tribute Cato in this weekend's "The Hunger Games" ... but the actor playing him wasn't always so intimidating.

Before starring in one of the biggest movies of the year, the 19-year-old Canadian actor was mostly known for his work in "Race to Witch Mountain" and "The Seeker," where he was considerably smaller.

Measuring in at roughly 6'2", Ludwig went through a major growth spurt since those movies and packed on 30-40lbs. of muscle specifically for the role of the ruthless killer from District 2.

"Training was definitely very vigorous," Ludwig tells toofab about preparing for the role. "I did lots of hand-to-hand combat, swords training."

For him though, it's been even hardest getting back to his pre-movie weight now that he's finished filming.

"I'm still trying to go back to my normal size, it's been so tough," he says. "It's way harder to lose weight than to put it on. It's so much easier when you just have to eat a lot ... I have so much sympathy for fat people, I don't know how they do it, when people are like I dropped 25 pounds. How do you do that?!"

Check out more stars who seriously bulked up for a film role in the gallery above!

For more coverage of "The Hunger Games," including reviews, photos and more, be sure to check out toofab's Movies You Love page here!