"I like the new me," said Locke in the June 18 issue of OK! Weekly. "I feel healthier. I feel sexier. I feel prettier."
The 29-year-old was one of eight celebrity cast members who competed on VH1's Celebrity Fit Club 5, but said she was initially "hesitant" to appear on the reality weight-loss series.
"I've always been really comfortable with my weight and my body," Locke told OK!. "I had to decide if I was up for the challenge. Once I made the commitment, it was scary because I knew I couldn't fail with America watching. That would be humiliating."
"I never dealt with [my weight] until I got into the industry and Hollywood," Locke explained to OK!. "I'm from the South, and all my friends are big, so if you saw them, you'd be like, 'Oh, you don't have a weight problem.' But when you get to Hollywood and you're the biggest thing walking around, the weight shifts - literally."
Dropping from a size 12 during her Idol days to her current size 8, Locke is a spokesperson for Jenny Craig and said she plans to continue to use the popular weight-loss program to reach her original goal of losing 40 pounds.
"I'm almost there," she told OK!. "For me, it's about being healthy. There are so many girls in magazines with eating disorders. I think young girls need a positive role model. I want people to know that if I can do it on my crazy schedule, then you can do it too. I want to let people know it's not easy, it's not a quick fix. I've been doing it for six months and I still have 10 more pounds to go."
Locke is also putting her money where her mouth is, as she recently visited New York City's North General Hospital to support 54 nurses there who are on the Jenny Craig program with a goal to lose a combined 1,800 pounds.
"The ladies are loving it. It's inspiring to see them do it," Locke told OK!. "These women have an amazing support group. I emphasize to people all the time that having a support group -- whether it's one person or 50 -- is so helpful."
Gaining the confidence to wear dresses and still keeping-up with her weight-loss goal by exercising regularly and carefully watching what she eats -- Locke encouraged other women to feel comfortable in their own skin -- which will in turn empower them to live a healthier lifestyle.
"I want young girls and women to know that they need to love themselves the way they are," she told OK!. "You can't make changes to yourself if you don't have a healthy relationship with your body. Once you do that, you can make healthy changes instead of trying to get that quick fix."