Rob Kazinsky Admits He's Been 'Incredibly Tempted' to Take Steroids, but Got Jacked for 'Star Trek' the Old-Fashioned Way. Here's How

Rob Kazinsky is one of those actors who you've seen in a million things. The 41-year-old has starred in blockbusters like Warcraft and Pacific Rim, which, in both cases, showcased his massive physique in tandem with his acting. For Kazinsky, his body is part of what he does; if he were a musician, it would be his instrument. 

This is why it's so refreshing that he's open and honest about when he's not at his best. In 2024, he posted an inspirational transformation video to Instagram, one in which he demonstrated exactly what it took to transform a version of himself he "didn’t recognize." So, what's his no-frills rule for replacing fat with muscle? 

"It's my 80/20 diet," Kazinsky tells Men's Journal. "It's in my head. There's no science behind this whatsoever. I'm just making this up. But this is what works for me." 

Recently, Kazinsky co-starred alongside action legend, Oscar-winner, and former Bond girl Michelle Yeoh in the Paramount+ streaming movie Star Trek: Section 31. In the new flick, Kazinsky is an absolute tank, playing Zeph, a partial cyborg, wearing a mech suit even bigger than what he hauled around in Pacific Rim. We caught up with Kazinsky to get more down-to-earth fitness pointers for guys over 40, what it was like to live his Star Trek dream, and what he learned about centering himself from Michelle Yeoh.

Men's Journal: That Instagram transformation last year was really incredible. You look massive and in shape now. What additional training did you do for this particular movie?

Rob Kazinsky: Having worn a suit like this before for Pacific Rim, I knew it was going to be severely taxing physically. It was going to be really hard, especially on my back and my spine. So, I was like, okay, if I'm going to get through this, I need to have solid, muscular core strength. And to be clear, in my career, I've never taken an anabolic. I've never taken those in my life. But, I've been incredibly tempted. For this, I went on a pretty hard 80/20 diet. That's 80 percent clean, 20 percent dirty. You can have a little treat. I don't believe that anybody can be perfect. And I don't believe that you can get healthy by doing a fad.

What's your advice for guys who are getting a bit older, and are maybe, I don't know, on a 50/50 diet?

You can't do something for three months. Fitness is cumulative. It takes a long period of time. So you have to be able to do it nonstop day in, day out for a year. You have one soda a day instead of six. Or you don't have dessert. Or you have one chocolate bar instead of six chocolate bars. You try to live as clean as possible for 80 percent of the day or 80 percent of the week. And that, for me, over a period of six months meant that the weight started stripping away.

Camden Boxing Gym is near me in London. I was mixing that in with my jiu jitsu and just really trusting in the flexibility of my muscles. And that came with kind of staying on my feet and building up my calves with boxing. I had to think about how I would have to use my body as my tool. Because it also was all me doing all the stunts.

So, you've now been in an action movie with the legendary Michelle Yeoh. What was that like?

Well, this is the sad thing, man, because even though I'm in many fight scenes with Michelle Yeoh, I don't get to fight Michelle Yeoh. And if there was anybody I would like to have a screen martial arts fight with, it's a short list: Chow Yun-fat, Donnie Yen, and Michelle Yeoh. So, we were sitting there lamenting and playing around between takes. She'd be doing spinning back kicks into my chest and it was so fun. I hope that if we do a sequel that me and Michelle get to go head to head.

Did you learn anything from Yeoh in terms of fitness?

She reminded me of all the things you have to do to preemptively take care of yourself. Michelle wakes up every day and stretches for two hours before she comes to set. And as you get older, that is the kind of stuff you have to do. Man, when I was 25, I could eat what I wanted and I was ripped. But when you're in your 40s, that doesn't work anymore.

So you've done Marvel, and Pacific Rim. Now you've done a Star Trek project. What else is on your bucket list? 

Yeah. Well, I've been really lucky. I got to do Warcraft obviously. When I was asked to do Captain Marvel, I was like, I don't care what I'm playing. I'm in the MCU. Pacific Rim. I get to do all these great things. But Star Trek's my big fandom. It's the thing I love most. It's the thing I grew up with and I know it, I'm as passionate about it as I am probably about any other single thing in my life. I never thought I would get the chance to be part of it.

I don't know what I did in a past life to deserve this life, but I must have been a quality human being. I think Star Trek offers a type of morality and hope and a beacon of who we can be, who we should be, and who we must be to everybody. And so to be a part of that, I think it's more than a dream come true. It's everything.

Star Trek: Section 31 is streaming on Paramount+.