Nicole's Post-Baby Bod

It's only been a few weeks, but Nicole Richie is back to her old, super-skinny self. The "Simple Life" star made her first appearance since giving birth to daughter Harlow Winter at a party for Hollywood agent Benny Medina in Los Angeles on Friday night. Nicole, wearing a black form-fitting dress that spotlights her already svelte bod, is surely the envy of moms everywhere - but can this super-quick weight loss be healthy for the new mom?