The bulked-up singer, 22, took sexy shots for Details and dished on how he got that hunky new body. He explained that the makeover was inspired by his role as a MMA fighter on the DirecTV series Kingdom.
"I had about six weeks to put on 12 to 15 pounds of muscle before filming started on Kingdom," Jonas told Details. "My character is a fighter whose strong suits are wrestling and grappling."
Jonas' quick transformation was thanks to an increase in calorie intake and some serious exercise.
"Diet had a lot to do with it," the "Jealous" singer said. "I went from consuming about 3,000 calories a day to 4,200… Breakfast was usually an omelet with veggies and cashew cheese, a turkey-meat patty, and some fruit; lunch and dinner would be lean protein, veggies, and nuts; snacks consisted of things like snap peas with peanut sauce."
"I don't have the luxury of eating whatever I want whenever I want anyway, because of my type 1 diabetes, so I have been conscientious about food for a long time," Jonas added. "I do have guilty pleasures, though. I wasn't drinking at all while I was training for the show, but now that we're done, I keep it classy with Coors Light."
As for his exercise routine, Jonas worked with a trainer in West Hollywood, Calif., and did three workouts a day. "I was doing three sessions a day: one fight-training with Kingdom's coach, Joe 'Daddy' Stevenson, and two strength-building with [trainer] Gregg Miele," the star explained. "Each workout focused on a different region of the body — upper body, core, or legs — and we'd do a circuit of six different moves for one area. Lifting a lot of weights, really trying to break the muscles down."
Jonas, who noted that he "got pretty Hulk-ish" while filming Kingdom, said he did not keep up the routine after the show. The former Jonas Brothers singer cut back to 2,500 calories per day and three or four workouts per week — a schedule he is perfectly happy adjusting to.
"I'm not the kind of person who wakes up in the morning and can't wait to work out," he admitted. "I kind of dread it, actually. I see it as a necessary evil."
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