Nyla Gibson was 300 pounds overweight, and found herself emotionally and physically affected by her past.
"I have friends who have waists smaller than my thighs," Gibson, a former high school state champion weightlifter, said.
A big part of the emotional problems that led to her weight gain was never having met her father.
"I've never seen my father," the Houston woman said. "I can't quite wrap my mind around how you can bring a child into the world and just leave them. And it makes me feel like, 'well, why am I not good enough?'"
Gibson has an MBA, but hasn't been able to find a job in her field. She believes her weight affects the way that potential employers perceive her.
"My greatest fear is that this is as good as it gets," she said.
The first time Powell weighed Gibson, reality set in, and she acknowledged that she was deeply afraid of failing.
"She had unrealistic expectations coming into the process," Powell said today on "Good Morning America." "She thought that I had some kind of secret."
"A lot of people do," Powell said. "They think I just show up at your doorstep and I sprinkle some magic pixie-dust and you lose 200 pounds but the magic is really what's in all of us. That's what I wanted her [Gibson] to know, that I can't lose a pound for her. She is the miracle in this process."
Gibson's inability to face her fears also threatened to jeopardize her weight loss goals. But Powell didn't give up on her. He hired a private investigator to track down Gibson's father.
She learned her father committed suicide in 2010, and the knowledge devastated her. She broke down. But learning about him -- and meeting her father's side of the family -- also helped her commit to her weight-loss goals.
"Dealing with my emotions in order to address the root of my problems was the most difficult thing for me," Gibson said today on "GMA." "Once I got that taken care of then I was able to kind of get things in gear and keep moving."
At her final weigh-in, Gibson tipped the scale at 278. She had lost a total of 157 pounds.
Gibson has maintained her weight-loss by finding an activity she is passionate about, Zumba.
"I liked it so much that I became an instructor," Gibson said of the Latin-inspired, high-intensity dance workout. "It's just a new way to challenge myself."
Finding that passion is something Powell says is key for anyone looking to maintain a healthy weight and a healthy way of living.
"You find something that you absolutely love and you run with it and you embrace it and that's what makes it a lifestyle," he said.