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Celebrity trainer Ron Mathews first started working with Joe Manganiello about six years ago, when the actor was cast in HBO’s “True Blood.”

When they met, Manganiello was 6’5” and 240 pounds, and Mathews remembers him saying, “‘I want to get bigger; I want to be muscular.’ And I told him: ‘Actually, you need to get smaller.”

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It’s related to the camera adds 10 pounds rule: “When you do a slow workout, you tend to look big in person, but you you look a bit floppy on screen,” he explains. “Taking his body fat down makes muscles pop onscreen.”

But Manganiello had to push his regime (detailed in the book he and Mathews worked on together,“Evolution”) even further for the male stripper sequel “Magic Mike XXL.”

“For ‘Magic Mike,’ he wanted to look really big and cut,” Mathews says. “It’s a very physical role with the dancing; it was about looking good, but also moving well with coordination like an athlete. It was about training to be able to perform, as opposed to just standing there in front of the camera and looking good.”

Training meant working out six days a week — twice a day. Mornings were cardio (on an empty stomach), then in the afternoon or evening Manganiello did weight training. The workout takes about an hour, including a warm-up and a cool down, and it is very fast, with few breaks. “The idea is to keep his heart rate very high,” says Mathews.

Between 40 and 60 minutes of cardio: jogging, rowing or cycling

The right diet is a huge part of the regimen, and Manganiello was a dream client. “He is incredibly disciplined,” says Mathews. “The good thing about him is that he doesn’t need a lot of variety, so if you tell him that’s what you need to eat, he will do it over and over again.”

When you’re working toward a fitness goal, Mathews says, food is not for pleasure; it is just another tool. Manganiello ate six meals a day, roughly 500 to 600 calories each, with 30 per cent protein, 30 percent fat and 40 percent carbs. Each meal is pretty similar and consists of eggs, chicken, vegetables and rice or potatoes. The calories could also come from a big salad or sushi, as long as you go easy on the rice.

“When trying to lose fat while keeping your muscle, you need to make sure you get enough calories, because if you don’t you will lose muscle,” explains Mathews. “You need to be able to maintain your frame and have enough energy to pursue your workout.”