Are the quick ways stars shed post-pregnancy pounds safe? An expert weighs in.

New celebrity moms don’t waste any time when it comes to getting their pre-pregnancy bodies back once they’ve given birth. Many are showing off their slim post-baby bodies in just a matter of months—sometimes even weeks—after their deliveries.

While celebrities may have access to top trainers and dieticians, the extremes they go to return to their pre-baby weight aren’t necessarily the safest or healthiest methods. Victoria Beckham and Kim Kardashian are two celebrity moms that have reportedly followed strict regimens to quickly get their bodies back after their daughters were born.

Toronto based Registered Dietician Stefanie Senior explains what about their diets works and what they should have done differently.

14 02 ceelb baby weight loss21) Victoria Beckham

Beckham apparently only gained 21 pounds during her pregnancy with her daughter Harper, but that didn’t stop her from starting her post-baby weight loss plan just days after she gave birth in July 2011.

The designer’s goal was to get her svelte figure back in time for her line’s runway show during New York Fashion Week in September. In addition to running six days a week, she reportedly stuck to the ‘Five Hands’ diet, which restricts food intake to just five handfuls of food a day with the choices of smoked salmon, prawns with chili, yellow-fin tuna sushi and scrambled eggs.

“In terms of her [Beckham’s] diet, it’s a pretty protein heavy diet. The reason why they [Beckham and Kardashian] are on a low carbohydrate diet is that when you restrict carbohydrates you lose water. You can lose a lot of water in the first couple weeks but not fat,” explains Senior.

“Carbohydrates are your main energy source so you aren’t fueling your body or brain properly and you can feel very tired, have poor concentration and some people experience changes in mood as well as sleeping problems.”

14 02 ceelb baby weight loss2) Kim Kardashian

Kardashian was constantly criticized for her appearance and 50-pound weight gain while carrying her daughter North West. Six months after her daughter was born, she was back in the spotlight showing off her famous curves.

The reality star reportedly followed the Atkins low-carb diet with a meal plan included lean meat, eggs, dairy, fresh veggies and fruit with gradual additions of grains like brown rice and whole wheat pasta and omitted processed foods.

“Atkins can be less than 50 grams of carbohydrates a day, when it’s recommended that most adults get 150 grams of carbohydrates a day. You can only absorb 20-30 grams of protein in one sitting so with these high protein diets you basically convert the rest of it into sugar or fat so you may as well have a balanced diet where you wont initially see a dramatic weight loss on the scale because you aren’t losing water,” says Senior.

While both of these celebrities’ diets were successful in helping them lose weight fast, in the long-term, low calorie, low carbohydrate diets may not be the best choice.

“The thing with post pregnancy is that moms need extra calories if they are breast-feeding,” explains Senior. According to Health Canada, most breastfeeding women need about 350 to 400 extra calories each day for the first year of breastfeeding depending on how much milk they produce and how quickly they lose weight once they’ve given birth.

It's best to avoid low-carb diets and focus on balancing out your meal plan if you're hoping to keep yourself and your baby healthy and happy after giving birth.