David Corenswet’s Superman diet and workout transformation for James Gunn’s Superman film involved an ambitious commitment: over several months, Corenswet gained 40 pounds of lean mass by following an intense, 4,500-calorie meal plan and a robust exercise regimen led by trainer Paolo Mascitti. Focusing on consistency and discipline, Corenswet prepared his body for the role through seven carefully structured daily meals and functional strength training at gyms, combining nutrition, exercise, and rest as pillars of his success.
Building Strength and Size for Superman
Trainer Paolo Mascitti’s approach did not simply focus on Hollywood aesthetics—his goal was to ensure David Corenswet could move and perform stunts like Superman. Their collaboration started in July 2023, encompassing up to six gym sessions per week. Instead of splitting the week by muscle group alone, their structure emphasized a push-pull-legs rotation: pressing movements on one day, rowing and pulling exercises like deadlifts the next, then a day devoted to intense lower-body workouts. The cycle repeated itself, pushing for regular muscle adaptation.
The backbone of Corenswet’s transformation was progressive overload—continually increasing weight or repetitions to spur muscle development. Activities centered on compound lifts, like bench presses and deadlifts that worked several muscle groups simultaneously. Each session concluded with focused isolation moves such as bicep curls and cable flies to fully exhaust targeted muscles. The rep range typically stayed between six and twelve to maximize muscle size, while finisher sets would sometimes stretch to twenty reps for optimal fatigue.
A vital aspect for Corenswet, given the stunt work and use of harnesses on set, was maintaining a strong and resilient core. Core training was integral to every session, establishing a foundation for performance and injury prevention. Uniquely, Corenswet found motivation in listening to jazz music—reportedly sculpting his physique to the sounds of artists like John Coltrane.
He had a very, very good attitude and he worked really hard. He listens to jazz when he works out.
—Paolo Mascitti, Trainer
The 4,500-Calorie Superman Diet
Moving away from typical Hollywood meal replacements, David Corenswet’s nutrition plan emphasized whole foods, precision, and gradual scaling. Under guidance from Business Insider’s reporting, his caloric intake started at 4,500 calories per day to drive lean mass gain, adjusting to 3,500 calories as filming neared to fine-tune muscle definition.
His meals followed a balanced macronutrient split: 50 percent carbohydrates, 30 percent protein, and 20 percent fat. Protein intake was calculated at roughly one gram per pound of body weight, drawing from eggs, dairy, poultry, beef, fish, and supplementing as needed with whey protein. A typical breakfast featured six egg whites, two whole eggs, oats topped with berries, Greek yogurt mixed with almonds, and a protein shake—a powerhouse combination to launch his day.
Lunch and dinner consistently paired rice or sweet potatoes with lean meats and colorful vegetables, targeting nutrient density and flavor. Corenswet consumed seven meals daily, carefully spaced to optimize energy for workouts and recovery times.
However, a strict plan did not mean a joyless diet. Trainer Paolo Mascitti highlighted that the actor had a soft spot for cereal, indulging in it as a rare treat. Occasional appearances by French toast and waffles broke up the discipline with small moments of comfort.
He loves cereal, that’s his kryptonite.
—Paolo Mascitti, Trainer
While nutrition and exercise received much attention, Mascitti also underscored the essential role of rest and recovery. For Corenswet, sleep became a critical piece, scheduled as seriously as each workout. After all, physical transformation depends on quality recovery as much as on protein shakes and squats.
Commitment Beyond the Gym
David Corenswet’s rigorous transformation hinged on the interconnected balance of diet, training, and rest—no element could be neglected without risking loss of progress. As his trainer noted, the entire process worked like a complex puzzle, and even one missed piece could set back results.
Everything is part of the puzzle. You take one of the things out and it’s not going to happen.
—Paolo Mascitti, Trainer
The discipline and effort Corenswet brought—whether during jazz-filled gym sessions, clockwork meal times, or relentless focus on sleep—reflect not just on the surface appearance but the substance behind his Superman transformation. Mascitti’s push-pull-legs protocol, combined with a carefully crafted macronutrient plan and the determination to meet filming demands, shaped Corenswet into James Gunn’s vision for the iconic hero.
With Superman set to premiere in theaters on July 11, 2025, fans and enthusiasts are eager to witness David Corenswet’s transformation on the big screen, marking a new chapter in superhero cinema and the enduring legacy of Superman.
