Tyson Fury may be undefeated in his 29-fight pro boxing career, but the lineal heavyweight champ and The Ring‘s No.1-ranked heavyweight has had his fair share of struggles outside the ring.

In October 2016, Fury vacated the WBA, WBO, and IBO world championship titles he’d won in his upset over Wladimir Klitschko in November 2015. Fury also won the IBF championship when he defeated the Ukrainian powerhouse, but was stripped of it days later because he couldn’t fight the mandatory challenger due to a rematch clause with Klitschko. Less than a year later, the then-28-year-old Fury revealed that he was in the midst of a fight far more perilous than anything he’d faced in the ring: a battle with depression and addiction.

But these days, Fury’s positive outlook on life and dedication to fitness year-round have forged an athlete who’s a far cry from the man who relinquished those belts to focus on his well-being. Still just 31 and in his prime, Fury has made a transformation both inside and out, losing more than 100 pounds and prioritizing his mental health. In the time since his return, he’s made it clear that he’s sharp as ever—something he attributes to his lifestyle changes.

“I’ve always trained very hard, and I’ve always been very fit for my fights,” the 6-foot-9 heavyweight told Muscle & Fitness. “But in the past two years, I’ve not turned away from fitness outside of training camps for fights. I’ve lived a cleaner, healthier life than I ever have in my whole boxing career.”

After just two fights back from his hiatus, “The Gypsy King” took on WBC heavyweight champ Deontay Wilder in December 2018 in a match that led to a controversial split draw, with the crowd skewed in Fury’s favor. Now, on the heels of showing German boxer Tom Schwarz what it’s like to lose a fight, Fury is set to face undefeated Swedish fighter Otto Wallin on Sept. 14. Wallin may not be as recognizable as Fury or Wilder, but he’s ranked fourth in the WBA and is undefeated in his 20 pro fights. A win against Wallin will likely lead to an eventual rematch between Fury and Wilder in 2020.

Whatever the public’s opinion of the matchup or the hype surrounding a future fight, Fury isn’t looking past Wallin. But, as usual, his confidence is unwavering.

“I only take one fight at a time, and I just enjoy this training camp. I won’t pass opponents—I take every guy seriously and train accordingly for that opponent,” Fury explained. “I’ll get Wallin out of the way, and it’s all plain sailing for me and Deontay Wilder to rematch. I believe it’s the biggest fight of the century, but we’ve both got to win our own fights in order to get the fight of the century happening.”

Ahead of his September fight, The Gypsy King talked boxing, fitness, and the mental health recovery that changed his life.

M&F: There’s been a lot of buzz around your upcoming match against Otto Wallin. What went into the decision to fight him?

Tyson Fury: He was the highest ranked available opponent that would take the fight. A lot of the other guys were busy or not willing to fight, so I’ve got to give credit to a guy who’s stepping up to the plate. I’m undefeated, ranked number four in the world, and ready for war.

What unique challenges will he present for you?
He’s a tall southpaw, he’s young and ambitious, and he’s never tasted defeat before. They’re always awkward and hard to beat when they’ve never lost, and he’s got a great trainer in Joey Gamache from New York. I’m anticipating a good fight, a tough one.

Are you more wary of an opponent like Wallin, having been the up-and-coming guy in the past?
No, I’m not worried. I can only train hard and do the right thing in training camp, and what will be will be, you know. I can’t do any more than my best, and if it’s not good enough, then it’s not good enough, but I’m sure it will be good enough on the day.

You seem to be in the shape of your life right now. How has your training evolved over the years?
It’s not so much been the training that’s evolved, it’s been my lifestyle that’s evolved. I usually would’ve had a fight, trained really hard and got in great shape, and within a month after the fight I’d be terribly out of shape—like a hundred pounds over what I should be. And that would be the lifestyle: the food, the drinking, the not training all the time, not having a proper training program.

Over the last two years, I’ve maintained my weight even while I’ve not been training. It was always training camp, get out, go wild, training camp, and vise-versa same again, and again, and again. It took me until 28, 29 years old to realize that. Life is so much easier when you come into training camp and you’re already 80% fit and ready.

How did you manage to turn things around and go from struggling with mental health issues to making a successful comeback?
After I had a mental breakdown like 18 months ago, two years ago, when I came back I had a different outlook on life. Things I used to stress about and all the things I used to care about don’t really matter to me anymore. The most important thing for me to do now is just keep mentally well, keep healthy, and stay fit.

I stay in the gym and enjoy what I love to do, boxing, and I take every day as it comes. I suppose we can never look too far into the future, and I give myself short-term goals rather than long-term goals. Staying active and staying fit makes me happy and well, so I’ll continue to do that throughout my career and life.

Do you have any tips for people who are struggling with the things you have?
Yeah, you know, if people are suffering with mental health issues, they need to go see a doctor immediately. And how I started to get well again was I worked out a training program—a little bit of training every morning, and what I could manage. It doesn’t need to be a lot, maybe it can be 10 minutes, or 20 minutes, or an hour, whatever you can manage as a person, and keep that routine going. I believe keeping a set routine in your life and having short-term goals, whatever they may be, they’re very, very useful for people who suffer with mental health problems.

Outside of getting your typical boxing training, what does your regular fitness regimen look like?
I run every day, I do cardio every single day of my life. While I’m not in the training camp I do cardio in the morning and weights in the afternoon. With weight training, I’ll break it up over five days, doing a different body part every day.

Things have been dynamic in the heavyweight division lately. What are your thoughts on the division overall right now?
I think the heavyweight division’s on fire. I think it’s a thriving division, it’s gaining momentum, and I fights like me and Wilder are setting the men from the boys basically—showing them how it’s done and how you step up to the plate in championship fights. I think the heavyweight division is as hot as it’s been since the days of Mike Tyson, Lennox versus Holyfield, and all that. I’m happy to be a part of it.

You’ve guaranteed a knockout in the potential Wilder rematch? What makes you so sure?
I have to get a knockout because I’m not going to get a decision like last time. I clearly won last time, everybody in the world knows I won, and I only got a draw, so I can’t leave it to the judges’ scorecard in this fight. It’s not going to be a point decision this time, it’s going to be a knockout either way. It’s either going to be him or me.

What do you think would be your next goal, if you do beat both Wilder and Wallin?
I don’t have any goals with boxing anymore. I’ve achieved every goal I ever set out to do: becoming heavyweight champion of the world with five different organizations, becoming Ring Magazine heavyweight champion, lineal champion—there’s nothing else I can achieve in boxing. I’ve won everything there is to win, so I’m not out to achieve anything. My only goal in life is to stay happy and contented.

Tyson Fury will take on Otto Wallin on Sept. 14, 2019, at the T-Mobile Arena in Las Vegas.