A funny thing happened on Junior Albini’s quest to lose weight: He became an MMA fighter.

As a morbidly obese teenager, the 26-year-old Brazilian need some exercise to get to a healthier weight. It soon opened the door to combat sports.

“I started boxing at age 13,” he told MMAjunkie. “I took up boxing because I weighed 165 kilograms (364 pounds). I had morbid obesity. I needed physical activity to lose weight and improve my health. I boxed for about a year.

“At 14 years old, I started jiu-jitsu, and I stayed active in both while still going to school. At age 18, I (turned pro). Now, after eight years, I’m in the UFC. My initial goal was just to lose weight, but I ended up enjoying fighting, and I stuck with it. There was no long-term plan.”

Now Albini (13-2 MMA, 0-0 UFC) makes his promotional debut tonight at UFC on FOX 25, where he takes on fellow heavyweight Timothy Johnson (11-3 MMA, 3-2 UFC). The early preliminary-card fight streams on UFC Fight Pass from NYCB LIVE in Uniondale, N.Y., prior to the FOX-televised prelims and main card.

Although his quest for a healthier lifestyle has now led him a contract with the world’s most prominent MMA organization, his family initially wasn’t happy with the turn of events.

In fact, his nickname – “Baby” – was the result of his protective mother.

“I was very young when I joined my first professional academy,” he said. “I showed up with my mother. She told them that despite my size, I was just a big baby, and that they should take care of me. And that’s how I ended up with the nickname.”

So what did Mom think of the eventual decision to make MMA his career?

“My family originally supported my going into martial arts for health reasons,” he said. “But once I decided to become an actual fighter, none of them supported me. They were all against it. That was eight years ago, and the UFC wasn’t getting this type of media coverage (in Brazil).

“Actually, the only person who backed me up from the start was my father. He always motivated me. And when I was 18, two days before my professional debut, he passed away. He was the only one who supported me from the start.”

However, some quick success and prominence kept him motivated, and his family eventually warmed up to his career choice. Albini, who trains at OCS Jiu-Jitsu (John Lineker’s team), won his four four pro fights before back-to-back submissions loss from 2011-2012 – part of a tough run at light heavyweight that ultimately proved too much – slowed the hype. However, the heavyweight is now on a nine-fight winning streak with seven stoppages that opened the door to the UFC.

Now here, he’s got a tough test in Johnson, who’s No. 12 in the official UFC rankings (but unranked in the USA TODAY Sports/MMAjunkie MMA heavyweight rankings). However, Albini knows he’s a bit of an unknown to Johnson, who’s unlikely to find much fight footage of the UFC newcomer, Albini said. Still, he expects a game opponent.

“He’s a difficult and awkward opponent because of his takedowns and pressure against the cage,” he said. “But in any fight, the matchup of different styles dictates how things play out. I believe he was a bad matchup against Marcin Tybura. Likewise, he lost to Jared Rosholt because he wasn’t used to that. So I’m betting on (the fact) I have a style Tim isn’t used to. I’m looking to take advantage of that.”

Now, he just wants to prove that his journey from dieter to MMA fighter was a wise one – and one that can support his own family.

“This is a chance of a lifetime, to give a better life for my wife and daughter,” he said. “I’m going to win or die. I’m very focused and highly confident that I’ll get the win.”

For more on UFC on FOX 25, check out the UFC Rumors section of the site.