Jonathan Tucker has that lean and hungry look. About to be seen on season two of the MMA-centered Kingdom—arguably cable TV’s sweatiest, angst-iest, most brutally two-fisted family drama. Count on the super intense, charismatic Tucker (Parenthood, Justified) to once again grab the focus of fans and critics with his acting chops and his scary, almost Christian Bale-esque physical transformation.

For those late to the party, Tucker plays a self-destructive, troubled fighter, the black sheep of a financially-strapped, massively screwed-up Venice, California family that includes his ex-fighter, gym-owner father (Frank Grillo), his drug-addicted, prostitute mother (Joanna Going) and his sexually-conflicted, fellow fighter brother (Nick Jonas). And then there’s his rivalry with a father’s favorite fight, played by Matt Lauria.

This year’s plot twists (no spoilers) call for Tucker’s character to be even more insanely ripped and shredded than before. Even in his stylish blue suit, one look at Tucker tells you that he doesn’t go in for half-measures. He’s been exercising and dieting like a freaking demon. So, as we’re sitting in the lounge at the legendary Beverly Hilton Hotel, it’s no wonder he’s eyeing the trays of food as servers go by.

What are some of the big changes your character experiences on Kingdom this season?
The competition between Matt Lauria’s character and my character, Jay, really ramps up. I get a new love interest played by Jessica Szohr. Jay giving himself the opportunity to have this new relationship takes away his focus and forces him to make comprises which he ends up regretting. I love seeing my character in new situations. My wife and I have a new puppy and it’s so wonderful to see him meet the world and react to everything. Jay’s like that or like watching a five-year-old tasting something new. Jay loves suits, art, his new girl—whatever takes him out of the gym.

You’re looking more even intense and startling than usual. What’s been going on?
That’s why my eye goes right to every plate of food that gets walked by. For the show, I went on this calorie restriction diet, going from 170 pounds to 140. That’s super lean at 5’ 10”.

That’s also a big weight cut.
I limited my daily calories to between 1,000 and 1,500. That’s very different from what you would do normally. It’s not healthy. It’s not fun. And nobody should ever really do it except for a short time—like 10 days—because you want to gain the weight back. That’s your advantage when you’re fighting. But because of the way we shot, I had to do it for a month. I’m glad I did it, but it was messed with me. As an actor, I do this animal work and I try to pull these different traits from animals. With animals, it’s always about food and hunger—how they get it, where they see and smell it. I’m all over that. I’m all about full fat.

There couldn’t have been that much full fat in this diet. So, what was on the menu?
Because I fasted, I had to increase healthy fats. For breakfast, I did Bulletproof Coffee—two tablespoons of unsalted, grass-fed butter, medium triglyceride oil and hot coffee blended together. Then, nothing else until one in the afternoon and for that, some of my standards were Whey protein, goat milk, bananas, blueberries or cold-pressed juice of kale, parsley, no sugars, and especially no apples, which are just cheap filler used by juiceries to increase profit margins.

How did you handle cravings for snacks?
You want to find healthy substitutions that will gratify that. I am a texture guy. I need to have chips and salsa, so I get Superseed Mary’s Gone Crackers instead. I’ll do five of those a week and the middle of the week, cucumbers. I’m on a regular diet for the show where I’m eating better than I have ever have and better than anyone I know. But the other diet was one where it was like, “Dude, you can’t have two oranges today and you have to have a half banana in a shake”.

How did it feel being on such an extreme regime?
Terrible. By definition, I was, literally, starving. Without the fat and calories, your mood and your sense of happiness changes. I got grumpy, snippy and short-tempered. I had to hyper-focus on certain things and then I’d be totally off in the middle of the clouds. At the same time, I do yoga, which changed my life, I meditate twice a day and I do a barre method class that is the hardest thing I’ve ever done.

How did people close to you react?
It put a nice friction in my relationship with my wife. She’d say something to me and I had to I tell her, “Babe, I love you so, so, so much. There’s no right answer, so, please stop. Just stop.” We couldn’t go out to dinner, which is something we really enjoy. Doing this show is not conducive to going out to dinner. But there are countless wives and husbands of MMA fighters who’ve gone through this very same thing. Matt [Lauria’s] wife and she are pals, so they have that common experience.

Was it worth it?
Oh, yeah. Our bodies are capable of performing at levels for periods of time and doing without things far beyond what we know. I mean, think of the people who go out to sea and get water from all sorts of sources. Mothers lift cars to save their loved ones—extraordinary things—the only thing I was up against is my mind. Finally, I began to think, “I can do this all year.” That’s why doing a show about combat sports is such fun, it’s never about the other guy, it’s always about yourself.