Hollywood icon Matt Damon spilled the beans on his biggest lifestyle change he made while preparing for Christopher Nolan's The Odyssey. "It's just a complete, complete lifestyle change," the Oscar-winning actor said. "I literally... stopped eating gluten," he said on Amy Poehler's Good Hang podcast, adding that he only realised how much gluten had been affecting him after cutting it out completely.ALSO READ: Sonam Wangchuk hunger strikeWhat turned out to be more surprising was that the 55-year-old said the dietary overhaul helped him reach his lightest weight since high school. The changes left him feeling so much healthier that he has continued the gluten-free lifestyle long after filming ended.Matt Damon reveals the diet change that transformed his healthMatt Damon has opened up about the lifestyle change that helped him achieve the "lean but strong" physique Christopher Nolan wanted for The Odyssey. 'The Instigators' actor revealed that eliminating gluten from his meals completely changed how he felt every day.ALSO READ: This 17-year-old is commanding nearly 300 US Navy cadets"It's just a complete, complete lifestyle change," he said. "I literally... stopped eating gluten." "We didn't talk about it, and I didn't realize the level to which it was affecting me. It's completely changed my life these last couple years of not eating it," he said.The actor added that the benefits far outweighed the sacrifice.Why Matt Damon stopped eating bread, pizza and pastaMatt Damon admitted he has always been a fan of bread, pizza, pasta and beer. Giving up those foods was one of the toughest parts of his transformation."It's a bummer. I'm a big fan of bread and beer, and pasta and pizza and all that stuff, but... how I feel is just so much better," he said. Even after filming wrapped, Damon chose to continue following a gluten-free lifestyle because of how much healthier he feels.The pizza moment that revealed Matt Damon's strict dietFans recently got another glimpse into Damon's new eating habits during an appearance on The New York Times Cooking's The Pizza Interview, where he appeared alongside co-star Tom Holland.As the pair prepared custom pizzas together, Holland noticed Damon wasn't eating any of the slices.The reason was simple: Damon had completely removed gluten from his diet, meaning traditional pizza, bread and many other carbohydrate-rich foods were off the menu.Matt Damon reached his lightest weight since high schoolMatt Damon also discussed his physical transformation during an appearance on Travis and Jason Kelce's New Heights podcast. According to the actor, Christopher Nolan wanted him to look "lean but strong" for the role of the legendary Greek hero Odysseus.To achieve that look, Damon combined months of intense training with a disciplined gluten-free diet. He revealed that he normally weighs between 185 and 200 pounds (84-91 kg) but slimmed down to 167 pounds (around 76 kg) for the role."I haven't been that light since high school," he said. The actor added that having a clear target made it easier to stay disciplined throughout the demanding preparation.Matt Damon says the gluten-free lifestyle is here to stayUnlike many Hollywood body transformations that end once filming is complete, Matt Damon says this one has become permanent.The actor revealed that he now follows a completely gluten-free lifestyle and has even switched to gluten-free beer."I'm done. I'm gluten-free everything," he joked. "It's been so long since I've had gluten, I can't tell if it's good or not."For Damon, what started as preparation for one of Christopher Nolan's biggest films has turned into a long-term lifestyle change that he believes has significantly improved his overall well-being.The Odyssey release dateDirected by Christopher Nolan, The Odyssey is set to release in Indian cinemas on July 17. The epic adaptation features an ensemble cast including Matt Damon, Tom Holland, Zendaya, Robert Pattinson, Anne Hathaway, Lupita Nyong'o and Jon Bernthal.As anticipation builds for the film, Matt Damon's gluten-free diet and remarkable body transformation have become one of the most talked-about aspects of his preparation for portraying the legendary Greek hero Odysseus.