(CNN) -- When Rachel Frederickson won season 15 of "The Biggest Loser" in February, her new look was met with more criticism than praise.

After shedding 155 pounds, the 24-year-old voiceover artist received backlash from fans who thought she looked unhealthy. Now heavier, Frederickson has penned an essay for Today's "2014 Voices" section to address the controversy.

Frederickson explains that she moved to Germany at a young age after falling in love with a foreign exchange student. That relationship turned unhealthy, she said, and "It didn't take long before the voice of a boy I loved started diminishing my self-esteem. His voice told me I wasn't enough and I believed it. I started listening to a louder voice than my own, and in turn, I lost the person I loved being."

Appearing on the show, she said, was where she "learned that my voice had to be stronger than everyone else's."

"From the beginning, no one thought I would make it to the final three and dismissed me as a finalist that could actually win," Frederickson said. "But I was there to get my life back."

Some deemed her dramatic transformation from 260 pounds to 105 pounds too drastic, and Frederickson felt the pressure of the disapproval.

"Comments during the controversial storm following my weight loss were hurtful. My self-esteem once again was affected by other people's voices -- this time, the kind that live forever in Facebook posts or written in the pages of magazines," she wrote. "People tried to bring me down and (privately) succeeded."

Frederickson, who has revealed that she gained 20 pounds after the finale, said she is now happy, healthy and in a good place.

"I found strength in this struggle," she said.