Credit: Paul Drinkwater/NBC © NBC Universal, Inc.; Trae Patton/NBC © NBC Universal, Inc.

Last night, 24-year-old Rachel Frederickson took home the title of Biggest Loser in the Season 15 finale, dropping a record-breaking 59.62 percent of her total body weight. The former competitive swimmer was proud to show off her newly-tiny figure in a shimmery silver dress, but some are now saying that she took her weight loss too far.

Rachel weighed in at a mere 105 pounds for last night’s finale — down from her 260 pound starting weight. And while her slim-down helped her to clinch the win over the other two finalists, David Brown and Bobby Saleem, and earned her the grand prize of $250K, her nearly unrecognizable appearance clearly startled more than few people.

For one, fitness coaches Jillian Michaels and Bob Harper were unable to hide the shock on their faces when Rachel walked out (at left), with Jillian seen mouthing “oh my god.” And viewers seemed to feel the same way, with an overwhelming number of people tweeting their concern over the dramatic weight loss — some even adding the hashtag #anorexia.

“#Biggestloser - Always inspired me but this finale was disturbing. They need safeguards to ensure [sic] contestants stay in the healthy BMI range,” writes one fan of the show.

Adds another viewer: “Oh no. I feel like Rachel lost too much. I actually feel concerned. I had to turn away. #BiggestLoser.”

What was most jarring for Biggest Loser followers was the difference between Rachel’s Makeover Week weight, and her current size. The episode aired only two weeks ago (though admittedly was filmed probably around two months ago), at which time the L.A.-based voice artist was a healthy 150 pounds.

We’re not doctors, and we don’t like to assess someone’s weight. We just have to applaud Rachel for her hard work on the show and hope that she’s using healthy means to maintain her fitness.

Did you watch the finale? What was your reaction to Rachel’s dramatic weight loss? Tell us in the comments below.

Samantha Lear is an Assistant Editor at Wetpaint Entertainment. Follow her on Twitter and Google+!