Jackson / Retna Digital 1 / 6
Jackson / Retna Digital 1 / 6

By Rebecca Silverstein

Gunnar Peterson has trained some of the biggest names in Hollywood, from Kim Kardashian to Jennifer Lopez. And now you can get a body like these sexy stars. Yes, you! On May 21, Gunnar will start the Gunnar Challenge, an eight-week online exercise program, which includes workout videos, meal plans and more. We snagged some time with Gunnar between clients to chat about his new venture, his favorite trainees and how to get a celeb-like bod. (Psst! If you enter the code MSNWW05 when you sign up for the Gunnar Challenge, you'll get it for just $49. But hurry -- you need to register before May 21.)

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Wonderwall: How did you come up with the Gunnar Challenge?

Gunnar Peterson: I'm all about real stuff and stuff that works, and I don't mind telling you there's work involved. I thought, "Why do fitness programs fail?" And they fail for two reasons. One, there's not enough variety in the workouts that people put together for themselves, and two, there's that "I'm on an island" feeling. This is a way to put community behind it. You have access to me, and there's community support: There's online, there's apps. It's very doable.

WW: How does the program help you get a celeb-like body?

GP: You'll have access to everything you'll need in terms of workouts, in terms of motivation. Having access is everything, to the information, to a trainer, to what you're doing and how to do it properly. I mean, I don't remember the last time I did anything so intricate and detailed -- giving you the exercises, the how-tos, the cues.

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WW: Over the years, you've worked with some of the fittest women in Hollywood. Who's been your favorite to train?

GP: Whoever is there that hour. I mean, it's like which one of my kids do I like best? They're all good, and what's fun is, what I noticed the common denominator with all the people at the top, is the work ethic. It's showing up; it's being consistent.

WW: You currently train Kim Kardashian, Sofia Vergara and Minka Kelly. What are some of their favorite workouts? What are their least favorite workouts?

GP: I usually don't get into favorites and least favorites -- not meaning with you, but with them -- because we are moving at such a good clip. You're on, you're off. I write a different program for every person, every day. That way, not only does your body not have time to get used to it and then start to stagnate, but mentally, you are always engaged because you don't know what's coming next.

WW: How do you get a booty like Kim's?

GP: Well, you have to make sure you are consistent with the workouts. You have to make sure you make good food choices outside of the gym. I don't ask you to be perfect -- nobody's perfect -- but make good choices overall, and you'll see results a lot faster.

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WW: We recently spoke to Vanessa Lachey, who said she's working out with you through her pregnancy. How have you altered her workout to accommodate for the baby?

GP: Well, you have to remember that when you are pregnant -- don't take this personally -- it's not about you right now. It's about the fetus. You're automatically a silver medalist, so you have to bear in mind what can the body take, what's healthier for the baby, and so you push the person, but this is not about trying to get you in a certain pair of jeans or trying to get you ready for a certain ball gown. This is about getting you ready to have as comfortable pregnancy and birthing experience as possible, getting it so when you do fire up your comeback post-baby, you're not starting so far behind the ball that it's ominous.

WW: How many days a week do these women workout?

GP: Depends on the person. Some of them are two times a week, but then they do two things outside of your week. Then some of them are six days a week and won't go anyplace else but here. And it depends on the person at that time -- some of them are two times a week for a while, then they bump up then they bump down; some are always all the time. It just depends.

WW: So you don't necessarily have to work out every day?

GP: No, but you do have to do something for your body every day. It doesn't have to be fire and brimstones, personal records every time, but it is to challenge yourself.

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WW: Why do you think celebrities are drawn to your method of training?

GP: I think they're just drawn to my gym because I have paparazzi-free parking. You can pull in and it's my parking lot, so they can't come in. That's a major deal! I think this. One, I try to be the one constant in their lives. The gym looks the same, feels the same, smells the same. It's like if you check into a Four Seasons, you always know you're going to get this level of service; the room is going to be this size. I try to appeal to them. I'm all for getting down and dirty in the workout, but I don't think there needs to be gum wrappers on the floor to make it a spit-in-the-corner kind of gym -- that's not what I'm doing. I try to provide a constant, something they can rely on. I just had a client, a pop star girl, that was in China for two days that was doing a private appearance, and she calls me and goes, "What do I eat? Because all the stuff isn't on the nutrition list," and I go, "No problem. Take a breath. Read me the menu. Here's what we do, and here's what we don't do," and we go down it. It was an eight-minute call, and it changed her trip.

WW: What celebrity would you love to have as a client?

GP: The one who would work the hardest. I have so much energy that I bring to this. I've been doing this for so long. I wake up, and I know it's weird and I know it's one-dimensional, but this is what I think about all the time. I don't care if you think about it all the time, but I want you to think about it; I want you to want to do this. I don't want you to be here because your spouse said, "Honey, you're getting fat. I don't want to have sex with you." I don't want you to be here because you go, "I really want to look good for my 25-year high school reunion and after that I'm good; I don't care." I want you to be here because you go, "I really want to make a change. I want to change the way I think about this."

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WW: How important is food in creating a great body? What diet do you have your clients follow?

GP: Food's important, and the further you get along in your progress, the more important food is. You know, don't jump in and try to do some weighing-your-food, calorie-counting thing out of the gate. It's a vital part of working out.

WW: What advice does you have for women who can't afford a personal trainer and want a celeb body?

GP: Do the Gunnar Challenge, and work as hard as the celebrities. Don't think that they just wake up like that. They work at it -- they work hard, they work efficiently. That's why I think this kind of training works for people -- it's efficient and it gets it done. Now, I'm going to go rock Denzel Washington's world right now! See ya.