“I started working out when he was 4-weeks-old,” Cavallari, who welcomed baby Camden with fiance Jay Cutler in August 2012, told Us. “Breastfeeding burns 500 calories a day, so that’s been very helpful.” Cavallari also hit the gym to jog, but didn’t go overboard. “[I've been] taking it easy and not killing myself. I haven’t really been stressing about it either. I think that helps.”

“I don’t know if I’m bouncing back. I’m slowly crawling back,” the svelte star jokingly admitted to Extra two months after welcoming son Tennessee in October 2012. “You just have to be gentle and patient with yourself and just sort of, you know…slowly get back to your health.”

Eight months after giving birth to son Luca in March 2012, Duff — married to Mike Comrie — fit back into her size-26 skinny jeans. With the help of personal trainer Gabe Johns, the actress incorporated boxing, wind sprints and jump roping in her two-a-day workouts to accelerate her weight loss.

There’s only one person responsible for helping Faris get her smokin’ hot post-baby body back in record time: her son, Jack! “I think [my weight loss is] from hauling around the little guy,” the What’s Your Number? actress — who welcomed Jack with husband Chris Pratt in July — told E! News. “I’m trying to do it without help, so it’s been a lot of lifting.”

This new mom is foxier than ever! Gaining 23 pounds while pregnant with Noah, born in September 2012, the This Is 40 actress is slowly dropping unwanted baby weight — and isn’t in any rush. “I don’t want to kill myself trying to get back into shape because it’s not a priority right now,” Brian Austin Green’s wife has said. “I’m too in love with Noah and I don’t want to be away from him. I just want to be home.”

“I feel positive about how I’ve done so far and really good about the goals I have set,” the Weight Watchers spokeswoman — who welcomed daughter Maxwell Drew with fiance Eric Johnson in May 2012 — has said of her 50-pound weight loss. “Most people can tell a difference every time they see me, which lets me know I’m making progress,” added the star, currently pregnant with her second child.

“Y’all have no idea how hard I worked. I had to lose 60 pounds!” Beyonce told an audience at her May 2012 concert in Atlantic City five months after giving birth to her and hubby Jay-Z’s first child Blue Ivy. “They had me on that treadmill — I ate lettuce!”

During her second pregnancy with son Noah, born in May 2012, the Victoria’s Secret model strived to be “as healthy as possible.” Once Noah arrived (joining big sis Anja), Ambrosio revved up her weight loss by breastfeeding. “[That] and running after my kids,” Ambrosio told Us, adding that she often mixes up her workouts. “I love to do Pilates and SoulCycle and go on walks and surf at the beach.”

The petite Jersey Shore star slimmed down in record time after giving birth to son Lorenzo in August 2012. Taking special care to stay in shape while pregnant — opting to focus on back-strengthening moves and cardio — Jionni LaValle’s fiancee chose to breastfeed her son, which can burn up to 500 calories a day. “I love nursing my little man!” enthused the reality star.

Nick Lachey’s wife was hyper-sensitive about her diet while pregnant with son Camden John, and her sensible eating paid off in the time since his September 2012 birth. “The only gift I can give my baby right now is what I put in my mouth and how I am health-conscious about trying to stay active,” Wipeout’s Minnillo told Us while pregnant.

The Victoria’s Secret model — who married Kings of Leon’s Caleb Followill in May 2011 and welcomed daughter Dixie Pearl in June 2012 — turned to Pilates to slim down. “It really changes the way my body feels,” Aldridge tells Shape. “And after I finish, it’s like I’ve had a massage.” – Usmagazine