In her 20s, Kim Nielsen worked as a personal trainer. She was naturally in great shape, which led to a pro wrestling career. Her stage name? Desire.

But in 2003, an inexperienced wrestler landed on Nielsen at a bad angle during a match and broke the Roswell resident's back. Nielsen was knocked out of the ring for a year.

After a failed comeback attempt and pregnant with her third child, she started packing on the weight, ingesting way too many Oreos and doughnuts. In the course of the next seven years, Nielsen added more than 100 pounds to her 5-foot-8-inch frame and filled her closet with size 18 clothing.

When Nielsen joined NBC's "The Biggest Loser" reality show last fall, she tipped the scales at 252 pounds.

During four months at an isolated California ranch used by the show, she shed more than 100 pounds on a limited diet and up to eight hours of exercise a day, supervised by Atlanta trainer Dolvett Quince. Entering the show's finale earlier this month, she was the favorite to win its $250,000 prize.

But 21-year-old Jeremy Britt lapped Nielsen in the final six weeks. He was named the winner after losing a whopping 51 percent of his body weight. In comparison, the 38-year-old Nielsen slimmed down a still impressive 118 pounds over six months — 49 percent of her body weight. She now fits comfortably into size 4 clothing.

"[Britt] had more weight on him to lose," said Nielsen in an interview a week later. "And he's much younger than me."

Men generally have an easier time losing weight, she noted. Not surprisingly, nine of the 13 "Biggest Loser" winners have been guys.

For Nielsen to take home the $250,000, she calculated she would have had to lose another 12 pounds. "I haven't been 124 [pounds] since I was like 12 years old. That would have been really unhealthy. I would not have looked good."

In a post-show interview, she told NBC cameras: 'I've got my health back. I have my life back. I feel amazing." Later, though, she admitted she was "bummed out. I never expected not to win."

Since March, Nielsen has been working out consistently at Body Sculptor in Buckhead, a training gym run by Quince, who joined the show last fall as a trainer. Even early on, Quince said, he knew Nielsen's competitive drive would take her far in the competition.

"She's accustomed to being challenged. It was muscle memory meets mental memory. She came to the ranch with that."

Does Nielsen worry about regaining her weight? Nope. Her history, she said, is her advantage over many of the other participants on the show, most of whom were obese all their lives: "This is not new to me. This is who I was before."

For now, she continues to work out 90 minutes a day, spaces her food intake to every three or four hours and keeps her calories at no more than 1,200 a day.

She isn't sure what her next move will be, but a return to wrestling is probably not in the cards. It was brutal on her body a decade ago and wouldn't be any easier now. ("I broke ribs. I broke toes and fingers.")

And she's still haunted by that moment nearly a decade ago when her tailbone cracked in the ring. "I couldn't breathe. I remember grabbing my back and looking at the ropes and not knowing what to do."

In excruciating pain, she still finished the match. Organizers called the medics only when they saw her crying.Nielsen said she wouldn't mind returning to a less hazardous job like being a personal trainer, perhaps even at Quince's studio. And Quince is open to that: "She's a walking, talking billboard, a great motivator."

She knows "The Biggest Loser" has many critics, who say it gives people an unrealistic picture of how weight loss works. Indeed, an HBO documentary series that debuted this week, called "Weight of the Nation," singles out "Biggest Loser" for focusing so much on exercise and not so much on limiting food intake, which better drives weight reduction.

"We were secluded," Nielsen said. "We worked out six to eight hours a day. Most people can't do that with a job and kids. But I think the show still gives people inspiration and motivation."

- Rodney Ho discusses radio and TV on his blog: ajc.com/go/radiotv.