But after gaining back some of his weight in the years since, Hoover, 33, has a new goal for both regaining a leaner athletic body and teaching fans to achieve their dreams: Hoover will compete in the Ford Ironman World Championship in Kona, Hawaii, in October.
"I am super excited about it," Hoover tells PEOPLE. "The Ironman people offered me a special invitation, and I felt as excited as if I got on the Biggest Loser. Every day I wake up, I'm not just thinking like someone who has lost weight or is trying to lose weight. I am thinking, 'I want to be an Ironman.' That's a title that so few people have."
Hoover spends 25 hours a week training for the grueling triathlon, which consists of a 2.4-mile open-water swim, a 112-mile bike ride and a marathon 26.2-mile run. "As soon as someone says, 'This guy can't do it,' I'm doing it," he says. "It's going to show a lot of people who have the idea that an athlete is 5'10" and 160 pounds that a big guy can do this and it can be enjoyable."
Support from WifeHe also gets support from Suzy Preston, 33, the Biggest Loser contestant he married in 2006, as well as their sons Rex Timothy, 23 months, and Jax Paul, 8 months. "Our focus has changed from three-percent body fat to raising healthy children," Hoover says. "We don't want them to see us struggle. If the struggle is watching me cross a finish line, that's a whole different thing than struggling with weight."
Fans can follow Hoover's training on his Web site and follow the race on the official Ironman site.
There's no waiting for marathon action, however. Tuesday night's episode of Biggest Loser: Couples features the final four – Tara, Helen, Ron and Mike – running a full marathon while being cheered on by five past Loser champions.
"A marathon is tough," Hoover admits, "especially on a bigger body. But these guys have been training hard and they are athletes now. You become an athlete through that show."
And now, Hoover is bringing his athletic side back to the forefront. "I don't hide it," he says. "People see this guy was on the show and he still has struggled. I think people think you go on the show and you never struggle again and for some people they may not. But for the majority, they do. But I am a real person with a big responsibility [as a role model], and I welcome it. Our son Rex, if he is awake, he wants to be outside and he's always moving. I love it, and to have this on tape so one day he can say, 'My Dad was an Ironman' That's what I'm proud of."