(ABC) -For many Americans, the quest to lose weight is often lost. At 400 pounds, one woman's determination to climb to the top of a mountain changed her body and spirit.
It's before dawn at Yosemite National park and the mountains are barely visible. Getting to the top is a journey.
"I have to make it to the top of this mountain," said Caitlin Lokey.
Lokey faces, roundtrip, more than 16 miles, but she's determined.
"Half Dome was one that I wanted to do. It's always been in front of me. I just never thought it was possible," she said.
The first part of the hike, she's speeding up the mountain...driven by her friends, part-trainers, part-motivators. But something else was pulling her to the top, her dad, who died when she was 25.
"He taught me a lot about working hard for what I want," Lokey said.
She's been training for this climb for more than a year.
"Five years ago, I probably wouldn't have stepped foot in the park," Lokey said.
Back then, Lokey weighed nearly 400 pounds.
"I remember thinking to myself...this is ridiculous. I can't even hardly walk at all. I'd get out of bed and I'd almost fall over, and I was like something needs to change," Lokey said.
With gastric bypass surgery, she dropped eight dress sizes in one year.
"I know my dad is proud of me and wants me to keep going and do this. I am feeling it in my feet and my legs," Lokey said.
For the unprepared...the sub-dome is one of the hardest parts of the climb. It's the final ascent before the cables where your physical and mental strength is vital.
"This part right here is probably the hardest right now, because my body is starting to feel what we've been going through. The biggest goal of my life is staring me in the face," Lokey said.
"The human body is capable of doing some amazing things, and Caitlin has proven that to be true," Troy Kellenberger, Lokey's lifelong friend, said.
The final 400 feet, at times a vertical ascent, is arguably the hardest. It's on this part of the hike where people have died.
"This represents a lot of things...getting through so much pain and heartache," Lokey said. "Oh my gosh, that just happened...we're almost there. The fact that I just did that I didn't even know I could...I didn't think I was going to get this emotional. I can't believe that just happened."
Overcoming an obstacle never meant so much.
"I wish my dad was here to see all these things happen. He pushed me every step of the way, that's for sure," Lokey said.
A dome this size never seemed so small.
"This is the top of the world," Lokey said.
The top of the world…a job well done.
"This is one of the best days of my entire life," Lokey said.
For Lokey, something her dad would be proud of.
In other health news, the Spirit of Survival training program is underway. Whether you're just beginning to get in shape or want to sharpen your long distance running skills, this annual event to raise money for cancer research is 11 weeks away. Group training sessions meet every Saturday at 7 a.m. at Dick's Sporting Goods in Lawton. For more information about training sessions or to register for the Spirit of Survival event, go to www.spiritofsurvival.com.