green organic boots high heels cavallari kristin skinny pregnant So that's the secret!

Kristin Cavallari stopped by Organic Earth Bar in West Hollywood yesterday, and the new mom looks more skinny than before she got pregnant!

We now know, though, how she got in such amazing shape so soon after giving birth to son Camden. The reality star grabbed a green juice, and clearly all those antioxidants are helping her slim down!

The engaged 25-year-old must be in town working on her upcoming line with Chinese Laundry. The blonde beauty is developing her own range of stilettos, boots, and sandals that are set to debut in stores next month.

Little Cam must be proud of his mommy!