The Biggest Loser trainer Bob Harper has finally opened up about what he thinks of fifteenth-season champion Rachel Frederickson's dramatic weight loss.

After issuing a general statement on Facebook earlier this week that was void of any personal opinion, Harper discussed Frederickson's current 105-pound weight during a Thursday appearance on The Rachael Ray Show, which will air on February 13, E! News reported.

"What people don't understand is, when the contestants leave to go home... they're in charge of themselves," Harper told Rachael Ray in the interview, according to E! News. "So I had not seen her until that night, and so when she walked out, I was just kind of like, whoa. And I've been on the show since the beginning."

Added the professional trainer, "I was stunned. That would be the word. I mean, we've never had a contestant come in at 105 pounds."

Harper's initial statement just congratulated all The Biggest Loser contestants on their hard work and stated he's not comfortable discussing Frederickson's journey because neither he or Jillian Michaels trained her during the season.

Frederickson's weight dropped from 260 pounds to 105 pounds on her slim 5'5" frame. She lost 155 pounds total all season and ended up losing just about 60 percent of her body weight in order to claim The Biggest Loser's $250,000 grand prize Tuesday night. Her margin of loss was the highest percentage ever posted by any contestant in the history of the show.

Frederickson, 24, spent most of her time on The Biggest Loser as a member of Dolvett Quince's Red Team. In a Wednesday Facebook post of his own, Quince addressed his client's transformation and suggested 105 pounds will not be her final weight.

"Last night's Biggest Loser Finale has sparked a huge reaction and I do not want the day to end without addressing it. Biggest Loser is a journey which has its ups and downs. Please try not to look at one slice of Rachel's journey and come to broad conclusions. Rachel's health is and always has been my main concern and her journey to good health has not yet ended!!" Quince wrote.

Frederickson has a BMI of only 17.5, which is considered underweight for her height, according to the National Institute of Health.

However, Frederickson has continued to dodge questions on whether she feels she is now "too skinny" or "took things too far."