HARLOW: Welcome back. A man who once battled a serious eating disorder decided to take on the challenge of a lifetime racing against horses and their riders. Tom Fairbrother took part in a very unusual and grueling completion in Wales. His remarkable story is in this edition of "FIT NATION."</s>UNIDENTIFIED MALE: Man versus horse. A huge completion in a tiny welsh town. Over 600 runners battle 22 miles of steep and slippery terrain trying to make it to the finish before 60 horses and their riders.</s>TOM FAIRBROTHER, MARKETING EXECUTIVE, PARKRUN: I would like to win. To tell your friends that you beat a horse is very cool.</s>UNIDENTIFIED MALE: But to get here, Tom Fairbrother faced a far more serious challenge, a battle with bulimia.</s>FAIRBROTHER: People just assume it's like these young girls who suffer. I think I wanted to show that a guy in his 20s who was quite athletic was equally at risk.</s>UNIDENTIFIED MALE: So he started a campaign to raise money and awareness by running 10 marathons in less than a year. He has one to go, man versus horse.</s>FAIRBROTHER: The first horse that came past, I've never seen or heard anything like it. You could feel the ground and kind of hear it coming. It just seemed like a fitting way to end something that's been like a great journey.</s>UNIDENTIFIED MALE: Finishing third runner today, Tom Fairbrother.</s>FAIRBROTHER: I'm really proud. Doing this is hopefully showing people that you can recover and be stronger than you were before.</s>HARLOW: All right. Stay with me. Much more in our breaking news straight ahead. We'll be right back.
Man Versus Horse: The World's Strangest Marathon