Chase Mattson’s Training and Nutrition Routine for Gaining Lean Muscle

Chase Mattson’s account of gaining nearly 30 pounds of lean muscle offers a look at how one actor prepares for physically demanding roles. The 6-foot-3 model and actor says he now weighs 215 pounds, up from 185 during his modeling years. His approach combines regular training with planned meals, but it’s a personal routine shaped by his work and schedule, not a formula for everyone.

Mattson stars in Agent of Shadows, a vertical drama made with ReelShort and WWE. The production brought him into scenes with wrestlers including Drew McIntyre, Booker T, Jacob Fatu and Nikkita Lyons. Mattson says he was surprised by McIntyre’s size despite being a tall athlete himself. “I was told that Drew was a big guy and I was like, ‘okay cool, I’m a big guy,’ and then he came on set and this dude is a giant, man!” he told M&F. He says the two became friends on set.

A demanding circuit is part of his training

One workout Mattson uses is “Cindy,” a CrossFit circuit also associated with actor Tom Holland’s preparation for Spider-Man. It cycles through five pullups, 10 pushups and 15 air squats, repeated for as many rounds as a participant can manage. Mattson recalls expecting the workout to feel easy, then tiring by round eight on his first attempt. He says he has since reached 16 rounds and sometimes makes the squats harder by holding 40-pound dumbbells.

That progress describes Mattson’s own experience; it doesn’t establish what another person can safely or comfortably do. The circuit combines repeated upper- and lower-body movements with limited rest, so its demands depend on pace, fitness and how the exercises are performed. Mattson’s story also gives no information about how often he does the workout or how he adjusts it around recovery. Anyone considering a new, strenuous routine may find it useful to discuss their health and fitness needs with a qualified clinician or exercise professional, particularly if they have a medical condition or symptoms during activity.

The production itself added physical demands. Mattson says he performed WWE-style stunts on the ground while filming in desert heat, including a scene with Booker T, and felt sore for days afterward. He also visited WWE’s Performance Center and stepped into a wrestling ring. Recalling a chair stunt, he said, “They hit me with a chair, a real chair,” adding, “It’s harder than it looks.” These are details of a staged production and his experience on set; they don’t provide a general measure of what training or stunt work involves.

Meal planning helps him fit eating around family life

Mattson says nutrition became part of his preparation after he recognized that he had been eating too little as a model. He now tracks his macronutrients—the amounts of protein, carbohydrates and fat in his diet—and says carbohydrates are included in his current plan. He eats five meals a day and keeps some foods in a separate kitchen cupboard to make it easier to follow that plan at home, where he lives with four children and two dogs.

His food choices include bison, almonds in place of candy, and blueberries, which he associates with muscle recovery. The source doesn’t give details about his portions, daily nutrition targets or the evidence behind that specific choice of foods. Tracking and meal frequency are elements of his personal routine, rather than proof that a particular eating pattern is necessary for gaining muscle. A doctor or registered dietitian can help people weigh nutrition changes against their health needs, medications and preferences.

Family time and exercise sometimes overlap. Mattson says he brings his children into outdoor jogs and calisthenics, making movement a shared activity. The larger point is practical: his routine has to fit around parenting and work, as well as the demands of preparing for a role. His experience doesn’t show how quickly other people can gain muscle, and body weight alone doesn’t reveal changes in muscle and fat.

Short-notice scenes shape the routine

Mattson says a shirtless scene may come with as little as 24 hours’ notice, one reason he aims to stay prepared between projects. The schedule for Agent of Shadows also involved strenuous scenes and time in hot conditions, adding a different kind of challenge from his regular workouts. His quoted soreness makes clear that performing stunts can take a toll, even for someone who trains.

Mattson has also been named People magazine’s Sexiest ReelShort Star. He says he is now preparing to work on a traditional horizontal-format production, but didn’t share details. The clearest takeaway from his story is that the change from 185 to 215 pounds followed a mix of training and planned eating within the demands of acting and family life. It’s a snapshot of one performer’s preparation, not a promise of a particular result or a substitute for individual medical advice.

Agent of Shadows is streaming on ReelShort. Watch the series.

Follow Chase Mattson on Instagram.

More on the training mentioned in the story: Drew McIntyre’s workout and Tom Holland’s “Cindy” workout. Mattson’s People feature also names him Sexiest ReelShort Star.