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CHRISTINA CORES, THEN: 240 LBS.
"Girls ganged up on me and said, 'She's so fat,'" the Medinah, Ill., resident – who gained most of her weight in eighth grade after her father's sudden death – says of her high school years. "I was like, 'I can't live like this.'" So Cores began taking steps to shed the pounds, bringing "turkey sandwiches for lunch" and working out at Curves.
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CHRISTINA CORES, NOW: 118 LBS.
With healthier eating habits, circuit training and support from the online weight-loss community SparkPeople.com, the 22-year-old has lost a whopping 122 lbs. "Honestly, stepping on the scale and being able to say I've done something I never thought I could even dream of – that's the best thing ever," says Cores, who even cracked the Top 10 at Chicago's Columbus Day Queen pageant in July. "I felt beautiful and confident."
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VICTORIA FUCHS, THEN: 376 LBS.
Working at Geico's Woodbury, N.Y., branch, Tori Fuchs dreads one thing: the office party. "There is not one day that goes by where there isn't a birthday, anniversary or shower," says Fuchs, who has dropped 210 lbs. over the past three years with the help of Weight Watchers at Work, a group of about 20 colleagues.
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VICTORIA FUCHS, NOW: 166 LBS.
"It's the most amazing feeling," the 29-year-old says of her dramatic weight loss. "Being with people who are dealing with the same situation makes it easier." Fuchs's group meets every Wednesday to check each other's progress and swap recipes and tips. "It's like having family inside the building," she says.
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MARTY & GRACE MOOREHEAD, THEN: 568 LBS. COMBINED
"I hated seeing my reflection," admits Marty Moorehead, whose six-slice pizza indulgence and late-night burger runs had him tipping the scales at 363 lbs. by 2008. Instead of undergoing bariatric surgery at his doctor's suggestion, he started Dr. Siegal's Cookie Diet – and, in the process of shedding 182 lbs., inspired Grace, his wife of 33 years, to "get on the bandwagon!"
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MARTY & GRACE MOOREHEAD, NOW: 328 LBS. COMBINED
Marty, now 181 lbs., and Grace, now 147 lbs., go for 4-mile walks around their Gilbert, Ariz., neighborhood four times a week. "Now we can do more together," says Grace, who shed 51 lbs. from her once-205-lb. frame by giving up bread and pasta. "And we'll be around a lot longer."
For more inspiring weight-loss stories, pick up the new issue of PEOPLE, on newsstands Friday.