Courtesy Slimming World

Kim Wright was enjoying a day out with her family at Six Flags Amusement Park in Texas when they boarded the Batman roller coaster. To her humiliation, she couldn't fit into the seat because of her weight.

"I wasn't able to buckle myself in so they got three attendants over to push the buckle in and to force me in to be able to sit into the seat," Wright, 41, of Plano, told ABC News Tuesday. "It was extremely embarrassing, for both me and my children. Everybody was looking at me … and so at that point I decided I needed to make some changes in my life."

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A month later, in May 2012, the stay-at-home mother of three children joined Slimming World, a U.K.-based weight-loss organization that now operates in the United States.

She weighed 289.5 pounds, and suffered from apnea, high cholesterol and foot and back problems.

Sixteen months later, Wright has lost 112.5 pounds, and says she feels like a different person.

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"I have more energy. I know how to pick and eat healthy foods. I enjoy shopping again for clothes, because that was something that I never wanted to do because it was very embarrassing," she said. "I'm not ashamed of the way that I look. … I feel confident when I'm going out, and so it's definitely been not just an outside change, it's been an inside change also."

Wright said she started gaining weight during puberty, adding that she had an "unhealthy relationship with food." She had tried diet pills and popular weight-loss programs, and said was able to lose weight but regained it once the program ended.

In addition to making more informed food choices and attending weekly meetings at Slimming World in Lewisville, right now works out six days a week at Curves, and works part-time there to help coach other women on losing weight. She had never exercised regularly before.

Wright's transformation earned her the Woman of the Year 2013 title from Slimming World.

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While she is proud of her accomplishment, Wright, who now weighs 177 pounds, isn't finished yet.

"I'm still working on my goal," she said. "I have about 30 more pounds to lose to get my BMI into a healthy range."