Kim Kardashian revealed to People magazine that she has already lost 43 of the 50 pounds she gained while pregnant with her daughter North West. The reality star, who shed the weight in only four months, revealed to fans on Twitter that the Atkins Diet helped her get back in shape.

In an interview with People, she said she was determined to get her pre-baby body back and used the negative comments and criticism to motivate her.

"Pregnancy for me was a lot tougher than people saw on my show or from magazines," she said. "So to get back to feeling like myself just makes me feel good again."

Kardashian did say she was hurt by all the Internet memes that poked fun at her weight gain and maternity style but she tried to ignore it. At one point Khloe Kardashian jumped to her sister's defense blogging that people should be ashamed for criticizing a pregnant woman.

"Every day I would hear people criticize me, and it would affect me," she said. "Little by little, it would chip away at my soul. I wanted to tune out the media and my public life and ignore it all."

She credits her weight loss to the Atkins Diet, which is a very low-carb, high protein diet plan. The plan consists of four parts. In the beginning of the diet the person's carb intake is dramatically reduced and slowly reintroduced throughout the program.

According to the website, a person could lose 15 pounds in the first two weeks. Besides being on a strict diet Kardashian said she worked here and there. She was spotted going to Barry's Bootcamp and Pilates Plus.

"This was the biggest challenge of my life, and I still have some to go," Kardashian said adding that she eats about 2,000 calories a day on the meal plan. "But I feel so accomplished that I did this."

She has said numerous times that she had no idea her pregnancy would have been so difficult. On "Keeping Up With the Kardashians" she told her sisters that she truly believed her belly would be the only part of her body that would get big.

"I always envisioned that I would have this easy time just being pregnant, only my belly would get big," she said. "And it has just been so not that way for me. But sometimes, you just have to take life for what it is and enjoy the ride."

To celebrate the weight loss Kardashian recently tweeted a picture showing off her famous curves in a white one-piece bathing suit.