The 24-year-old voiceover artist began season 15 of The Biggest Loser weighing 260 pounds.
In order to lose all of the weight, the Rachel had to learn to cook more slimming foods.
Rachel builds some muscle with weight training.
With lots of exercise, Rachel began shedding some pounds.
The red team was all smiles while competing.
Rachel continues to develop healthy eating habits.
One of the best things about weight loss?! Shopping for your newly slim figure, of course! This lucky girl got tips from expert fashion consultant Tim Gunn.
Rachel is almost down to her end weight of 105!
Rachel awaits her results during the season 15 finale.
Rachel took home the top prize of $250,000 for losing 155 pounds!
Rachel models her new physique after her big win.
Several months after the show ended, Frederickson shared a pic of her 20-pound weight gain, writing, "I think I'm at my perfect weight."
MORE PHOTOS: Biggest Loser's most drastic weight losses