The 27-year-old shoe designer was photographed in a short romper, red booties from her Chinese Laundry collection and black sunglasses while heading to lunch at Fig & Olive on Wednesday.
The former star of The Hills told Access Hollywood in July that she's been working out hard and has been mindful about what she eats in an effort to lose the baby weight.
"I don't put any toxic chemicals in my body. I'm a freak about reading the ingredients. I don't count calories, I just read what's in whatever I'm going to be putting in my mouth," she explained.
Cavallari and her football player husband, Jay Cutler, welcomed their second son, Jaxon Wyatt, in early May. The pair, who married in 2013 after three years of on-and-off dating, had their first son, Camden, in August 2012.