Matt Damon has revealed that a significant dietary change, specifically the elimination of gluten, was key to his dramatic physical transformation for his role in Christopher Nolan's upcoming film, "The Odyssey." The Oscar-winning actor shared that this lifestyle adjustment has been life-altering, leading to a profound improvement in how he feels.

During an appearance on Amy Poehler's "Good Hang" podcast, Damon discussed the intense preparation for the film, where he aimed to embody the legendary Greek hero Odysseus. He noted that while he had attempted similar physical transformations before, this time felt different. "It's just a complete, complete lifestyle change," Damon said, describing the process as simply "putting your foot on the gas and that's it."

Damon explained that cutting out gluten was a pivotal part of this transformation. "I didn't know," he responded when asked if he still craved gluten, "because of what it does to me." He acknowledged that his generation did not grow up with the same awareness of food sensitivities that exists today.

"We didn't talk about it, and I didn't realize the level to which it was affecting me," Damon stated. "Like it's completely changed my life these last couple years of not eating it. 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."

Earlier this year, Damon had detailed the rigorous regimen he underwent for "The Odyssey." Speaking on the "New Heights" podcast with Travis and Jason Kelce, he mentioned dropping to 167 pounds, his lowest weight in decades, to meet Christopher Nolan's vision of a character who was "lean but strong."

"I literally, just because of this other thing I did with my doctor, stopped eating gluten," Damon recounted. "I used to walk around between 185 and 200 pounds. And I did that whole movie at 167 pounds. I haven't been that light since high school."

In addition to the strict diet, Damon also credited the guidance of a personal trainer for helping him maintain focus throughout the demanding preparation process. "Trainers are like, 'What are we doing?' And they can kind of do anything. It's just having kind of a clear goal and setting it."

This is not Damon's first experience with significant weight loss for a role. For the 1996 film "Courage Under Fire," he lost between 40 and 50 pounds in approximately 100 days. At the time, a doctor cautioned him that such rapid weight loss could have had severe health consequences, potentially permanently shrinking his heart.