Credit: Humberto Carreno/Startraks Photo: Kim Kardashian Heads to a Yoga Class in New York City on October 25, 2010
When it came to dropping from a size 6 to a size 2 at the beginning of 2010, Kim Kardashian had a different approach than her sister Kourtney. She followed a diet and exercise plan, but she also used the weight loss product QuickTrim, which she endorses.

Like Kourtney, Kim — who went from 124 to 109 pounds — has admitted the journey was more than a little tough. "There's nothing easy about being fit and healthy," she said. "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!"

"I have cellulite, just like almost every other woman on the planet," she added. "And just because I feel secure with my body doesn't mean I think cellulite is cute! It will always be an issue for me. So let's just say it's a work in progress!"

To work off the weight, she obviously had to make a few changes. "I finally said enough with the junk food," she revealed. "These days I prefer salads with grilled chicken or turkey burgers without the bun."
Credit: Norman Scott/Startraks Photo: Kim Kardashian Grabs a Smoothie After Working out in Los Angeles on June 26, 2010

She also worked out with Jennifer Lopez's trainer Gunnar Peterson and worked out at Barry's Boot Camp up to five times a week, according to Us Weekly. On top of that, she developed a DVD series called "Fit in Your Jeans By Friday" — a "quick paced workout" that promises a "more beautiful backside in less than five days!"

And while Kim was busy slimming down, so was her sister Kourtney, who was on a mission to shed the 40 pounds she gained while pregnant with son Mason. "My sister weighs less than I do, and she just had a baby — so that's kind of fascinating to me!" Kim, 30, told UsMagazine.com in April. "She looks amazing!"

"Definitely breastfeeding helps," Kourntey told Us. "Everyone says that, but it's really true — and it's just being a busy mom."

Sister Khloé added that she wishes she could drop weight as easily as her sister. "That's all it takes, breastfeeding?" she joked. "Then someone breastfeed off of me! I don't care!"

Sources: OKMagazine.com, Fitsugar.com, UsMagazine.com