Hey there, good lookin'! Kim Kardashian cut a slim figure while out and about in Los Angeles with bestie Jonathan Cheban on Saturday, Oct. 12 — and now we know why!

The first-time mom looked laid-back in a loose-fitting white quarter-sleeve top, distressed jeans and knee-high brown boots as she toted daughter North (snuggled up in a covered carrier) toward a waiting car. She wore her blonde hair down, a pair of oversized sunglasses her only hint of Hollywood glam.

One day later, on Sunday, Oct. 13, the Keeping Up With the Kardashians star told fans that the trick to her slim figure has been a strict practice of the high-protein, low-carb Atkins diet.

"I've actually been doing the Atkins diet & luv it," she tweeted.

"She is eating lots of lean proteins, healthy fats like nuts and avocado, carbs, fruits, veggies and cheese," a rep for Atkins tells Us. "She wanted to be a healthy, nursing mom and not toxify her milk with her diet or lose weight too quickly. She's been doing Atkins since her doctor approved it at the end of June."

Just one day earlier, Kardashian, 32, stepped out boldly in a clingy, low-cut grey dress that hugged her curves as she visited the DASH store in West Hollywood with sisters Khloe and Kylie Jenner.