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(CNN) -- Like so many people, Nicole Durham was tired of being overweight. No one bullied her, and she didn't have a health scare. She was just sick of looking and feeling bad.
When the Colorado woman finally decided it was time to lose weight, she knew she had a long way to go. She needed more than a diet to lose 100 pounds -- she needed to change her whole life.
So she approached it like a marathon instead of a sprint.
Durham weighed roughly 175 pounds throughout high school, but carried it well on her 5-foot-5-inch body. A decent portion of it was muscle from her sports training.
"Nicole was overweight, but it didn't ever seem to bother her," her mother, Denise Durham, said. "She had a lot of friends, was on the tennis team and always seemed happy."
But by late 2010, the then 25-year-old was at her heaviest ever, weighing 258 pounds. She was displeased with her weight, but still wasn't motivated enough to do anything about it.
"So many times I would tell myself, 'Today you're going to start making changes,' but I never did. Today always turned into tomorrow," she said.
In the fall of 2012, the accumulation of the little things -- seeing photos from when she weighed less, being afraid to hike with friends because of the physical strain, her hatred of shopping because clothes didn't fit -- finally became too much.
She was tired of the mental toll that being overweight took on her and fed up with feeling bad about her body.
"One day, I made sure today was today and started right then and there."
She wasn't the heaviest she'd ever been, but she knew that at 235 pounds, she had a lot of work to do. She started out with small changes, realizing that for her, quick and drastic would be a recipe for failure. She also knew she had to stay positive, or else this would never work.
"The exercise was the toughest part, as most people can attest to," Durham said. "I started slow. I walked a ton and danced my butt off, literally, with 'Just Dance' on my Nintendo Wii."
It was Christmas of 2012, only a few months into her weight loss, that people began to notice a change.
"When I saw her, I could tell something was a different, but I couldn't pinpoint what it was," her mom said. "We thought it was a new haircut, but Nicole's grandmother noticed right away that her face was thinner."
In January, Durham got serious. Although junk food had never been a vice of hers, portion control was a problem -- or rather nonexistent, she said.
She cut out desserts, buying sugar-free Popsicles or Jell-O to satisfy cravings. "White foods," such as pasta and bread, were changed to whole grains. She also cut back on alcohol when going out with friends.
"Beer and I basically took a break in our relationship."
Helping along the process was her work's annual weight loss contest. At the end of the 10-week challenge, she ended up winning by losing 21 pounds -- almost 10% of her total body weight. With her $90 in winnings, she purchased a bicycle.
Slowly, walking began to mix with jogging. Then it became jogging with a little walking. By summer, it became running, and her video games were shelved and replaced with strength training and biking.
Durham used a food app to help track her diet, ensuring a proper balance of carbohydrates, protein and fat. Her goal was to eat five to seven servings of fruits and vegetables each day. She also stopped drinking beverages that contained calories.
"I stuck to a simple mantra of eating less and better, and working out more," she wrote in her CNN iReport.
She hit her goal weight of 143 in November of 2013, one year after she started.
"I work hard, eat pretty conscientiously during the week and have fun on the weekends, now that I'm working on maintaining," Durham said.
Because her weight loss was a lifestyle change as opposed to a diet, she had to find a way to make it work long term. She knew realistically that she'd be indulging in things like pizza or beer on occasion, and wasn't going to starve herself to maintain her weight.
"I definitely don't feel like I'm missing out, because I work out to stay active and to balance it all."
She lost a little more weight after reaching her goal as she worked on finding a good balance of reintroducing calories without eating poorly.
Today she weighs 135 pounds, give or take a few. She doesn't feel bad shopping or looking at old photos of herself, and she's not afraid to do anything outdoors. Her mother is proud and says that her daughter's success and positive attitude have inspired the family to become more active and eat better.
Durham bicycles, hikes, runs and lifts weights. Outdoor activities are no longer stressful and daunting, but rather enjoyable and liberating.
It may have taken her years to get here, but for Durham, slow and steady won the race.