And the reality TV star mum has put the speedy weight loss down to the Atkins diet, tweeting: "I've actually been doing the Atkins diet & luv it", in reponse to a fan asking for her secret.
The 32-year-old is the latest in a long line of celebrities to try the famous low-carb diet, which has won its fair share of both praise and controversy over the years.
Created by Dr. Robert Atkins, the regime is Sharon Osbourne's favorite low-carbohydrate diet. Sharon is even a spokesperson for the food plan, which her rocker husband Ozzy and son Jack also follow.
More celebrity fans of the diet, which encourages followers not to worry about counting calories but rather focus on the amount of carbohydrates they're consuming, have included Jennifer Aniston, Demi Moore and Catherine Zeta-Jones.
Atkins works on the principle that limiting the consumption of carbs forces the body to burn its fat stores to get energy – a process known as ketosis.
Along with rapid weight loss, it promises to regulate your blood sugar and help you achieve optimal health, without leaving you feeling hungry or deprived.
Following the publication of Dr. Atkin’s second book, Dr Atkins' New Diet Revolution back in 2002, the diet reached its popularity peak a year later, with three million people in the UK having tried it.
The book was among the top ten on The New York Times bestseller list for almost six years, selling in excess of 15 million copies worldwide.
While Atkins says that exercise is not vital for weight loss, Kim has been combining her current diet with an exercise regime – she was spotted hitting the gym while in Paris and she is also said to have been visiting high-energy circuit training class Barry's Bootcamp in LA with rapper beau Kanye West.