Travis Colby's turning point came on the Maliboomer at Disney's California Adventure Park last December.
He couldn't get the harness to buckle around his 325-pound body, so an attendant asked him to get off the ride.
Twelve months later, he's lost 100 pounds and is ready to run the California International Marathon on Sunday.
Humiliation can be a great motivator.
"They tried to help force me into the seat," said Colby, 32. "I had to sit there and watch my family go on the ride. It was horrible.
"I always knew I was getting really big. It doesn't really hit you until you get a moment like that."
After spending the rest of that family Christmas trip "in a bad funk," he decided to change.
Colby, formerly of Citrus Heights, was once athletic – he played football at Del Campo High School in Fair Oaks. He now lives in Merced, where he is a deputy district attorney.
He figured enough was enough.
He ate smaller portions, cut out fast food, switched from diet soda to water – "That was probably the best thing I ever did" – and started running on a treadmill.
"I eventually built up to the point where I could run 30 minutes without stopping," Colby said. "It took me about three months to get there."
He signed up for a 5-kilometer race, started training for a half marathon and then decided to take his first shot at the 26.2-mile marathon.
"One thing led to another," said Colby, who is scheduled to wear No. 1454 on Sunday. "It felt so great to accomplish (finishing a half marathon), I just kept going."
The 6-foot, 1-inch Colby said a visit to the doctor before he began his workout routine reinforced his desire to lose weight.
"Basically what they told me is, had I not gotten in shape I would be at risk of a heart attack within 5-10 years and would most likely develop diabetes in the next five years," he said. "My risk levels right now are not any greater than the average person."
Eating better has played a big role.
"I make my own breakfast, make my own lunches, cook a nice dinner," he said. "I avoid anything fried."
Still, Colby isn't satisfied, saying he'd like to lose another 20-30 pounds.
His wife, Kendal, has provided plenty of support. She's lost 25 pounds in the past year.
"I'm so proud of him," she said. "He's one of those people that up and decides they're going to change one day. If you ask him to do it before that, he's not going to do it.
"I'm just really pleased he's really taken it to heart."
When her husband started losing weight, Kendal said she'd look for him on shopping trips and couldn't spot him.
"It took a long time for me to recognize him," she said. "That was the funniest thing about it."
Colby, who writes a blog about his physical transformation and marathon training, said he's happy his story can serve as an inspiration.
"I feel great to know my common-sense approach is helping not just me but others," he said.
Colby planned to go back to California Adventure but the Maliboomer ride recently closed.
"It's a part of my life now that's gone," he said. "It's time to move on."
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