Kourtney Kardashian shows off her svelte post-baby bod. Photo: Courtesy of OK! Magazine

Only a year after giving birth to her first child, Kourtney Kardashian is looking super svelte, and, according to what she's telling OK! Magazine, she's currently in the best shape of her life.

The eldest of the Kardashian sisters, Kourtney stars on the cover of OK! this week sporting a tiny blue bikini and showing off completely flat abs and an overall lean physique.

"I love my new body," the 31-year-old tells the magazine. "They say that it takes a full year to really get your body back [after giving birth] and I believe that."

Earlier this year, Kourney complained that OK! photoshopped her post-baby body and made her look unrealistically thin after putting on 40 lbs during her pregnancy.

Inside the issue of the new magazine, however, Kourtney dishes on her new exercise and diet plan, which is said to mix "healthy choices with a few splurges."

Of course, a love of fitness runs in the family. The most famous sister, Kim Kardashian (who is also the face of Sketchers Shape-Ups along with mom Kris Jenner) was the November cover girl of Shape magazine and admitted to working hard for the bod she's got.

"There's nothing easy about being fit and healthy,"says Kim. "I'd never say, 'Take this and eat whatever you want or don't work out.' That's not realistic. To look and feel my best, I watch my calories and exercise. And right now, I can honestly say I'm in the best shape of my life!"

And that makes two of them.

In related news: check out a host of other stars in barely there bikinis before taking a peek at snaps of the Kardashian clan's Christmas party.