David Corenswet's Superman Transformation
David Corenswet’s Superman Transformation (Photo Credit – Instagram)

David Corenswet has finally stepped into the red boots for James Gunn’s Superman. However, the process behind it all wasn’t a walk in the park. Guided by celebrity trainer Paolo Mascitti, the actor didn’t rely on movie magic or protein fads. Instead, he followed a punishing schedule of seven meals daily, five to six workouts a week, and serious sleep discipline. And the result is 40-pound muscle gain that was all grind.

Inside David Corenswet’s No-Nonsense Superman Transformation

When Paolo Mascitti signed on to train David Corenswet for Superman, he was prepping a real-deal action hero. And that philosophy ran through every rep and every bite. Speaking to Business Insider, Paolo shared the DC star’s workout and nutrition plan.

The program kicked off in July 2023, right before cameras began rolling. From that point, it was game on. There were five strength sessions per week, structured around an old-school push-pull-legs rotation that was anything but casual.

Each gym day focused on different muscle groups. One day was all about pushing power, like bench presses and overhead presses. The next was for pulling, like deadlifts, rows, anything that worked the back and biceps. And then came the dreaded leg day. This cycle kept repeating, and every session followed the principle of progressive overload.

The Real Deal is Relentless Diet Discipline

But the workout wasn’t the whole story. The real challenge came in the kitchen. David Corenswet needed to escalate to 4,500 calories per day throughout his mass-gaining cycle. His diet was made of whole, nutrient-packed ingredients. The macro Protein amounted to a gram per unit of body mass, involving plenty of eggs, dairy, lean meats, fish, and whey shakes.

A standard morning meal resembled the following: six egg whites, two whole eggs, oats, a handful of berries, Greek yogurt sprinkled with almonds, and a shake. And that was just meal one. To be precise, he ate that seven times a day!

Despite how strict it all sounds, there was room for indulgence, too. David Corenswet is only human, after all. “He loves cereal, that’s his kryptonite,” Mascitti shared. Occasionally, there was French toast or waffles, too. But the indulgences were earned, and they never derailed the mission.

James Gunn’s Superman released in theaters on July 11, 2025, and judging by Corenswet’s transformation, this Man of Steel brought more than just heat vision.

Stay tuned to Koimoi for more such fashion and lifestyle stories and updates!

Must Read: Warner Bros. Canceled Black Superman For Being ‘Too Woke’ — Could It Return Under DC’s Elseworlds Label?

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