( CNN ) -- Sara Lugger was skeptical as she placed her first $ 5 bet . But she realized that all she had to lose was weight -- and a few bucks if the money did n't motivate her to get in shape . A friend 's success had inspired Lugger to join DietBet , a website that hosts private and public games where people can bet on their own weight loss . Each game sets a goal , such as losing 4 % of your body weight , and users who reach that goal split the pot . Lugger was 34 and weighed 342 pounds . She had struggled with obesity most of her life . In the ninth grade , she was diagnosed with ulcerative colitis , and doctors put her on prednisone . The steroid made it difficult for her to maintain a normal weight . But in 2004 , Lugger had surgery to fix the colitis . `` From there on out , I could n't blame anything but my poor habits . '' Shortly after her birthday in February 2013 , Lugger decided that reaching 350 pounds would be `` unacceptable . '' The Oxford , Michigan , resident realized that her weight was holding her back from doing the things she wanted to do . She had been the heaviest person in her college classes , where she studied to become a physical therapist . And although family and friends never said anything outright , she noticed they did n't exactly try to set her up on dates . She avoided social situations and outdoor activities that might call attention to her size , and she worried about traveling because fitting in an airplane seat was difficult . `` For weeks before I flew , that would be on my mind , '' she said . After signing up for DietBet , Lugger made a plan . She threw out all the junk food in her house . She decided she would wake up 30 minutes early every morning to work out on her elliptical machine . Then , at lunch , she would use the physical therapy equipment at her office to strength train . That way , if she wanted to go out with friends in the evening , she would n't miss a workout . upwave : Do n't miss a workout with the one-minute workout challenge . `` I have never seen her so driven and persistent on a goal , '' her friend Travis Summerville said . `` I do n't know where that came from , but she chose a simple exercise regimen and diet style that worked well for her , and she just kept at it consistently . '' Lugger traded her morning bowl of cereal for a protein shake . She stopped frequenting fast-food places and instead used Pinterest to find lighter fare to cook at home . She now keeps to a 1,200-calorie-a-day diet . `` I 'm kind of an all-or-nothing person , '' she said . `` I ca n't ( just ) lean into things , or it does n't happen . '' Losing weight did happen . Lugger loved the support she found from her group on DietBet and signed up for two more games after the first one ended . Over time , she upped her bets to $ 10 and then $ 50 as she gained confidence -- and lost 140 pounds . Lugger 's friend Christie Williams has also lost 60 pounds using the site . Looking back , Williams is amazed at how heavy she and Lugger once were . But what she 's always loved about her friend is still there , Williams says . `` I do n't believe Sara has changed as a person . She still laughs loud , dances crazy and screams at the wrong parts in horror movies . What has changed is the activities we do . It 's not always takeout pizza and two movies . We 'll go walk a couple of miles or play `` Just Dance '' before we go out to eat . '' The friends are training for an upcoming 5K and helping each other maintain their slimmer figures . `` We are holding each other accountable , '' Williams said . `` My biggest fear was ( Lugger ) having a heart attack at age 45 . That fear is gone , and I do n't want it back . ... It 's never going to be easy , but it will be easier than losing her at a young age . '' Overall , Lugger has won more than $ 330 on DietBet . She 's also won a new outlook on life . Lugger used to tell her friends -- and herself -- that she did n't like basketball because she knew she would n't fit into the arena seats . Now she 's a Detroit Pistons fan . `` Turns out , I really like basketball , '' she said with a laugh . Lugger is also traveling more . And shopping . She loves dressing in clothes she feels express her style instead of trying to hide in the background . `` I 'm finding me more , and that 's a really neat thing . ''
At her heaviest , Williams weighed 140 pounds . Lugger joined Lugger and bet money she 'd lose weight . She 's lost 342 pounds and won more than $ more than $ .