Soon-to-be Superman Henry Cavill hasn't always been superhero fit; in fact, he said he's battled against his own weight though out his career.

The Man of Steel star told DETAILS that he was "Fat Cavill" in his youth, but has always been willing to make changes to his body in the name of furthering his career. He got himself whipped into shape for one of his first major roles, in a 2002 film adaptation of Dumas' The Count Of Monte Cristo, where he lost about 20 pounds.

"I wasn't Fat Cavill anymore," he said.

Indeed, the training Cavill had to undergo for Man Of Steel had him achieving a whole new level of fitness.

"We did some of the first shots in Plano, Illinois," said the actor, describing the intense regime. "They'd get me up at the crack of dawn, and we'd go to work in this tiny gym at the bottom of the very cheap motel we were staying in." Then the heat would really get turned up when, after hours in the gym, he'd be led out for lengthy shoots in 100-degree temperatures.

Cavill said he has let go a bit since the film wrapped and lost much of his superhero bulk -- "I'm not eating 5,000 calories a day anymore" -- but wouldn't reveal any more about how he's held up since then.

"It's modesty about the weight," he explained. "I've always been worried about my weight - but I also don't want to invite that debate: Henry weighs this, so he's the perfect Superman. Or, Henry doesn't weigh this, and therefore he's not believable in the role."

However, Cavill says he's always been serious about Superman and wants to make sure he's done everything right in his new movie, because he recognizes the importance of the character in popular culture.

"I want to get that right. I want to do it justice," the actor said. "I want people to believe in the character and have faith in the character and kids to grow up wanting to be Superman."

Tags: Henry Cavill Man of Steel