Days after sparking an onslaught of headlines and tweets concerned about her drastic weight loss, "Biggest Loser" winner Rachel Frederickson, who lost 60 percent of her original body weight, admits she may have gone too far.

"Maybe I was a little too enthusiastic in my training to get to the finale," she told People magazine, saying she was eating 1,600 calories and exercising for six hours each day during the three months leading up to the Feb. 4 finale in which she was crowned the season 15 winner.

Eating 1,600 calories a day is well within established guidelines for losing weight safely, but may be too few when such an extreme exercise routine is taken into consideration. It goes without saying that six hours of exercise a day is far and beyond the recommended two hours and 30 minutes of physical activity per week recommended for most adults. "Exercise addicts tend to think that a two-hour run makes them four times as healthy" as a 30-minute session, Arthur Allen wrote for WebMD. "It doesn’t work that way."

Even Frederickson's trainer on the show, Dolvett Quince, was surprised by her final weigh-in of 105 pounds, saying, "The first thing that went through my mind was, 'That's just too much.'"