Nearly three years ago Amanda Flick, tired of a lifetime of being overweight, decided to lose those extra pounds for good and hired a personal trainer to help her.

Today, Flick, 31, is 100 pounds slimmer and a personal trainer herself, working right alongside the same trainer who kick-started her life-changing weight loss.

Flick, of Kokomo, Ind., in turn helped change the life of her husband, Keith, 33, who, inspired both by his wife and a shirt he desperately wanted that didn't fit, dropped 90 pounds on his own.

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"We stopped going out to eat, started cooking healthy meals and, every calorie, we counted," Amanda Flick, who once weighed 223 pounds, told GoodMorningAmerica.com today.

"We used to order pizza every Sunday and eat an entire pizza," she said. "We don't do that anymore."

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Flick was first inspired to lose weight by a friend who was running 5-K races and posting photos on Facebook. In January 2010, Flick set a New Year's resolution to get active herself and began working out to Jillian Michaels DVDs and on the elliptical.

Once she started running, Flick lost weight quickly but then was sidelined by a knee injury that resulted in her gaining back 15 pounds of the 50 pounds she had lost.

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"I hired a personal trainer and he helped me get my knee better and got me running again," she said. "Working out is a hobby now."

Keith, a student who also works at a restaurant, helps by cooking the couple's dinner every night, always with fresh and healthy ingredients. In turn, Flick helps train her husband, often using CrossFit's workout of the day, posted on the company's website, as inspiration.

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"We both have more energy now and want to do something instead of sleeping all day, because that's what we would do," she said. "Now I'm at the gym at 5 a.m."

Flick, who also works as a massage therapist, says she has two tips for people who want to change their lives.

"First, if you mess up, and you will, start again at the next meal and don't wait another week or for the next milestone," Flick said. "Second, don't put a time-frame on it. Take it day by day."