Arriving at the ranch, Eberwein weighed 297 pounds, while Rothermel was 274 pounds.
"Watching my weight broadcast was humiliating because it took me back to when I arrived at the ranch. It was a down moment. It was hard to watch," Eberwein said.
For two weeks, their personal trainer, Jillian, put them through workouts and changed their eating habits.
"We were required to work out two to three hours a day with Jillian and then it was recommended to do one to two hours of cardio on our own. We ate a balanced diet -- we were advised to eat whole grains and wheat products, fruit, veggies and lean proteins -- and cut calories," Eberwein said.
Rothermel said the show produced unexpected results for the couple.
"I never expected the results that Sarah and I achieved and the workouts became easier and easier to the point that I had to really change my workouts so I could continue to lose weight," Rothermel said.
After watching many diets fail, Eberwein said the Biggest Loser diet is a lifestyle change that tailored to their individual needs.
"I have tried to lose weight many, many times and every time I did I gained the weight back after a few weeks. This time I was put into a full program that I had never gotten before, and I was immersed in the lifestyle so I had to learn a whole new way to live," Rothermel said.
Despite Jillian's harsh appearance on the show, Eberwein only has positive things to say of her personal trainer.
"She was tough and one of the toughest individuals I've ever met. But she was very passionate and caring," Eberwein said. "Tough when she needed to be and supportive when she needed to be. She was such a phenomenal person and can't say enough good things about her."
Only two weeks after arriving at the Ranch, all four contestants were weighed again. The blue team--Eberwein and Rothermel's competition--lost a combined 41 pounds off their initial weight of 477 pounds.
When it was time for Eberwein and Rothermel to weigh in, Eberwein admits to being nervous. "I remember how scared I was. I was freaking out because I had no idea how much weight I had lost," she said.
Rothermel weighed in at 244 pounds, losing 30 pounds in the two weeks. Eberwein had lost 25 pounds, bringing her new weight to 272 pounds.
"It was amazing to be able to do that. I never thought I lost that much. I had expected a 15-25 pound number and the 30 was amazing," Rothermel said.
His fiancée shares his same sense of joy and amazement. "Before I hadn't been able to lose an ounce. It was shock mixed with accomplishment. 'Look at me, I did this by myself. No one did this for me. The 25 pounds came off because I made it happen,'" she said.
Eberwein and Rothermel shed a total of 55 pounds, winning them the title of biggest losers on the ranch and a honeymoon to Jamaica.
"Winning was awesome. I told Steve I am going to get a string bikini to look cute on the beach," Eberwein said.
But winning the trip is secondary to the emotional changes they have undergone, said Eberwein, and losing the weight is giving them a new lease on life.
"I can be the person that I have always wanted to be but couldn't because I was fat," she said. "We've become much stronger as a couple. I have no inhibitions with Steve anymore."
With his new body, Rothermel has other plans for his future.
"I am going to be running a marathon in November and I plan on lifting more weights after that to gain a good 15 pounds of muscle. I want to be ripped by the time I'm getting married," he said.
The initial taping for the show began in April, and then the teams returned to their hometowns for the summer to lose the weight on their own. After leaving the ranch, Eberwein said that the training wasn't as hard as she thought it would be.
"We knew we had another prize to win. Working out on our own was easy, dieting was harder, but it was not as hard as I thought it would be," she said.
Although the final weigh-in was in September, the episode will air tomorrow night on NBC at 9, which will reveal the winner of the dream-wedding prize.