Former boxing heavyweight champion Andy Ruiz has put in the miles in the gym, landing himself in incredible shape as he looks to make a return to the sport's pinnacle.
The jovial American-born fighter shocked the world when he defeated British boxer Anthony Joshua via technical knockout in June 2019, which secured him four of the five heavyweight belts, along with unforeseen acclaim.
However just six months later, a visibly overweight Ruiz took on a lean and determined Joshua in a rematch, and went down via unanimous decision and losing the belts to the very guy he won them off.
A spate of criticism followed as Ruiz seemingly squandered his chance to stay on top of the sport's most popular division, in favour of indulging in the luxuries that came with his surprise success.
Ruiz told The Ring he took the period he held the four belts for granted.
"It happened too fast and I feel regret, because I lost it all," Ruiz said. "I knew I had a big fight against Anthony Joshua six months later, and me making my own training times and doing whatever I wanted, I have a lot of regrets over."
"Eddy [Reynoso, trainer] has brought out the discipline, the hard work and wanting to be hungry, and being around them, you want to be better. I want to be the heavyweight Canelo Alvarez. Success completely got to my head. It's why I say it was my lowest time. I was surrounded by the wrong people and I was depressed. I knew what I should have been doing—and I didn't do it.
"That's on me. I should have been more disciplined and closer to God. God gives and He takes away. I should have been more aware of who I am and what I'm about. I ask myself what would have happened if I won the Joshua rematch. I would have been worse. I needed to have that happen."
Ruiz – who became the first ever Mexican heavyweight champion – is not the first fighter to score an upset win and fade away just as quick, with his demise similar to that of Buster Douglas.
Douglas, a former heavyweight champion himself, famously defeated Mike Tyson in 1990, but lost his very next bout to Evander Holyfield and disappeared in a flash, failing to rediscover his footing in the sport.
Ruiz currently weighs 115 kilograms, but by the time he came round to his second fight with Joshua he weighed 128.4, 6.8 heavier than his first fight.
He admits he ballooned to as much as 136.1kg.
"I was partying with my friends, partying at the clubs, but I'll leave the dirty stuff alone. You can say I did turn into Buster Douglas a little bit after I won," Ruiz said. "There is a big difference with me in the ring now. I won't say my last team did not motivate me, but this is a different vibe that I get.
"I'm working and training with champions. I can't change time. There are a lot of things that I could have done. I'm lifting weights, which is something I never did before. I'm squatting and my legs look like giant hams. It builds confidence, and with that confidence I feel great."
A big part of Ruiz's recovery has been the work with his new trainer Eddy Reynoso and fellow Mexican fighter Canelo Alvarez.
"They told me, 'Once you're with us, there is no one that's going to beat you. You're going to become the best version of Andy Ruiz that you ever wanted to be. We're heading there," Ruiz said.
The 31-year-old puts his 33-2 record on the line, up against American Chris Arreola this weekend in his first bout since his defeat to Joshua.
"I'm fighting Chris Arreola coming up and I'm taking him seriously. Chris is a Mexican warrior like myself," he said.
"Hopefully, there won't be a lot of flab flying on me the night I fight Arreola," said Ruiz, laughing. "I let a lot of people down, which I won't do again."