At just six weeks postpartum, Kylie Jenner is promoting a problematic weight loss method.

At just six weeks postpartum, Kylie Jenner’s already racing against the clock to slim down fast – and she’s using controversial weight loss methods along the way.

The beauty mogul has followed in her sister’s footsteps, donning the Kardashian’s favourite slimming attire – the waist trainer.

The Keeping Up With The Kardashians star returned with her first sponsored Instagram post since the birth of her daughter Stormi earlier this week,  promoting a waist trainer that promises a “snap back” post-baby body.

Posting a mirror selfie to her 105 million followers, Kylie wrote: “My girl @premadonna87 hooked me up with the @waistgangsociety snap back package. #ad waistgang has the BEST quality snap back products.”

my girl @premadonna87 hooked me up with the @waistgangsociety snap back package. #ad waistgang has the BEST quality snap back products. make sure you get your package & follow @waistgangsociety to join & keep up the journey together. tag us in photos, and head over to www.whatsawaist.com NOW! Use code (Kylie) for an exclusive discount & I can keep up with your progress ‼️ #waistgangsociety #waistgang #fitness #whatwaist #whatsawaist.com

A post shared by Kylie (@kyliejenner) on Mar 19, 2018 at 12:12pm PDT

Fans were quick to call out Jenner for her post, claiming the promotion adds to the toxic post-baby body ‘snap back’ culture.

My god is kylie still advertising waist trainers (NOW POST GIVING BIRTH) to teenage girls !!! how can u be so filthy rich and still sell out for something that is so dumb and could potentially perpetuate negative body image in young girls

— ¿ Jackie ? (@jacq_dullea) March 20, 2018

As well as the added societal pressure these ‘snap back’ waist training tools put on postpartum women, they are also potentially unsafe.

Although many Instagram influencers and celebrities, including the Kardashian sisters, Amber Rose and Jessica Alba promote the products and their benefits, health professionals have revealed the products are somewhat ineffective and may be medically harmful.

Speaking about waist trainers to Women’s Health, Mary Jane Minkin, M.D., a clinical professor of ob-gyn at Yale School of Medicine said: “Medically, it doesn’t make sense that cinching your waist tightly will make it permanently smaller. Once you take the garment off, your body will return to its usual shape. It’s also uncomfortable, restricts your movements, and if you wear it really tight, it can even make it difficult to breathe and theoretically could cause rib damage.”

Listen: Should women stop the post-baby-bikini shots? The Mamamia Out Loud team discuss. Post continues below.

As for wearing a waist trainer so soon after giving birth, ob-gyn Sherry Ross told Parents, “waist trainers and belly wraps often claim that they can help relieve water retention and shrink the uterus faster, but this is in no way medically proven.”

Waist-training involves wearing a tight corset for multiple hours per day, including during workouts and meals.

If used alongside a healthy diet and exercise, the use of a waist trainer can supposedly make you lose 2-4 inches off your waist as they compress appetite and improve posture.

Would you use a waist trainer?