Sylvester Stallone knows exactly what it takes to build an action-hero body, and he doesn’t think audiences should assume those superhero-sized physiques are happening naturally.While promoting his new memoir, Steps, Sylvester Stallone opened up about the extreme transformation he put himself through for Rocky III, including a brutal diet, massive amounts of coffee and steroid use. He also offered a pretty candid take on the bodies audiences see in modern superhero movies, comparing the process of chemically bulking up for a role to putting on a costume.Stallone discussed the subject during a 50-minute conversation with Tracy Smith at New York’s 92nd Street Y. The appearance comes 50 years after Rocky first hit theaters and helped turn Stallone into one of Hollywood’s biggest stars.The actor has recently been talking more openly about what he put his body through during the Rocky years. He previously revealed that he was “bulimic” while making Rocky III and has spoken about the “terrible toll” steroids took on him.For Stallone, however, the drastic physical change wasn’t simply about looking ripped on screen. He wanted Rocky Balboa’s body to reflect where the character was emotionally after becoming successful.“By the time they did Rocky III, you’ve lost the element of surprise. Everyone knows what this guy is all about. I wanted him to develop serious narcissism. I wanted him to get his scars removed and be a totally different guy. “That would be a story point. He became protected, he’s shielded and vain. And when he finally met Mr. T, or Clubber Lang, that’s where reality hit him. But to do that, I had to do a total body metamorphosis. “So I went from like 50% body fat to 2.6%. I did it literally by eating tuna fish and [drinking] maybe 30 cups of coffee a day. And, of course, there’s steroids.”That confession got an audible reaction from the crowd, but Stallone responded by pointing out that steroid use and extreme physical transformations aren’t exactly foreign territory for Hollywood action stars.“Guys … you really think these guys are natural?” Stallone quipped. “If you’re trying to play a sort of superhero or a person that is above and beyond a normal guy, you can’t do it. It’s almost like putting on part of a costume. For six to eight weeks, you manifest that book. And then you shed it.”It’s an interesting way to describe the Hollywood superhero physique. Actors are routinely expected to transform themselves into comic book characters who look physically larger than ordinary people, and Stallone sees that temporary body as another piece of creating the character.Of course, pushing the human body that hard can come with serious consequences, something Stallone eventually experienced himself.Smith asked when he realized he couldn’t continue using steroids while maintaining such a punishing workout routine. Stallone said his “wake-up call” came after undergoing a heart valve replacement.His wife, Jennifer Flavin Stallone, noticed that something didn’t look right and pushed him to get examined. Stallone said that decision “absolutely” saved his life.“And I thought I was okay. I was lucky that my wife said, ‘I don’t like the way you look.’ [I said], ‘Oh, come on. I’m just getting old over here. Relax,’” he recalled. “Women have an extra sense. They really do.”Fifty years after Rocky, Stallone is now talking openly about what it actually took to create the larger-than-life body audiences associated with Rocky Balboa. Stallone’s memoir Steps is out now.Via: Variety