Frederickson, 24, lost 59.62 percent of her body weight to win the show, though her 105-pound frame prompted some viewers to wonder whether she'd dropped to an unhealthy weight.
Trainers react to Rachel Frederickson's weight loss on US Biggest Loser: pic.twitter.com/hdAg3dh13X— Karlos (@karlosmadden) February 5, 2014
Blimey! Just seen the pics of America's Biggest Loser winner Rachel Frederickson. Too much, girl. Too much. http://t.co/kmDpc1XPBo— Lorna Cooper (@Coops_tv) February 5, 2014
"Since the first season, participants have reported the alarming disconnect between what the audience is told about medical supervision and what actually occurs at the ranch," wrote Refinery 29's Kelsey Miller. "As early as season one, participants confessed to resorting to extreme dehydration in order to keep their numbers dropping."
Frederickson seemed happy about the outcome in her post-victory press call with reporters on Wednesday.
"You know, I think I have been on this seven-and-a-half month journey on The Biggest Loser and I went to The Biggest Loser to find that confident girl again," Frederickson said when reporters repeatedly asked her about criticisms that the show had let her "go too far."
"I was very enthusiastic about the finale and I'm really excited about my life here going into maintenance mode. I'm going to try new exercises and continue on this path and see where it takes me -- finding that balance!" she added.
"I feel like my journey on The Biggest Loser was my path and I followed the advice and has the support of the medical team at The Biggest Loser the entire journey," she said. "So it's just been natural and I've enjoyed every part of it."
Michaels and Harper released a joint statement regarding the issue on Twitter.
"Jillian and I want to take a moment to congratulate all of the BL contestants on their hard work. We're not comfortable commenting on Rachel's journey because we weren't her trainers and weren't given an opportunity to work with her at any point. Any questions about the contestants on the Biggest Loser should be directed to the show's producers," they said.
Trainer Dolvett Quince, who worked closely with Frederickson on the ranch, has not commented.