Photo: South Beach Diet

Jessie James DeckerCredit: South Beach Diet

Jessie James Deckeris feeling stronger than ever after three kids.

“I was in the best physical shape of my life after my second child, and it felt so good, so I couldn’t wait to get back there because I felt so healthy and felt so active,” Decker, 30, tells PEOPLE during the photoshoot for her new campaign with the South Beach Diet.

“Before, genetically, I could just do whatever and be thin,” she admits. “But after Bubs I had to work really hard, and I think after seeing these results I noticed muscles I never had before. I was super toned and I felt super fit and I just loved it. It changed my mental mindset, because it was all about feeling fit and feeling good.”

South Beach Diet

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At this point, Decker feels like she’s made tons of progress, but she has bigger goals in mind.

“I don’t think I’m 100 percent there yet,” she says. “I definitely think that I have a little bit of a ways to go, but I do feel really good now.”

Along with eating protein- and vegetable-packed meals, Decker works out whenever she can pass the kids off to her husband, the newly-retired NFL playerEric Decker.

“I’m weightlifting and it’s really fun, because I started at 5 lbs., and then I got up to the 10’s, and now I’m at the point where I’m using my 20-lb. dumbbells and I feel good. It’s a slow process but I can just see the gradual progress, and it feels great,” she says. “I’m working out even harder now.”

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And though she’s lost 17 lbs., Decker says she now cares more about her muscle tone than the number on the scale.

“I’m not a big scale person. I’m big on how I look and how I feel, and I’m all about building muscle and toning up,” she says. “I used to obsess over that stuff back in the day and I just don’t anymore. I think how do I look, how do I feel, how do my clothes fit me, and I’m all about getting in the gym. I love lifting weights and I love being active and I look and feel better from that.”

source: people.com