More than half a million people liked Khloé Kardashian’s Instagram photo of herself wearing a waist trainer underneath her workout clothes when she posted it a few weeks ago. And more than 46 million people follow her. But if anyone were to imitate this particular picture, not only would they fail to become magically slimmer, they could seriously hurt themselves.

“If you wear [a waist trainer] during exercise, it would probably compromise your ability to exercise at a high intensity,” Dr. Caroline Apovian, director of the Center for Nutrition and Weight Management at Boston Medical Center, told The Daily Beast. “In extreme situations, you may damage your ribs.”

Waist trainers are essentially modern-day corsets that use latex to cinch the abdomen rather than bones and laces. In the last two years, they have become a fixture on social media, especially Instagram, where stars falsely suggest that they can help women subtract inches from their measurements.

Kim Kardashian, Kylie Jenner, Amber Rose, Farrah Abraham, and Lindsay Lohan have all hawked them on the image-sharing service, showing off dramatic hourglass figures and directing their followers to online storefronts like WhatsAWaist.com, which promises that women who wear their shaping garment several hours a day can achieve “permanent waist-reduction.”

It’s the 16th century all over again, apparently. In fact, there is not much difference at all between latex waist trainers and old-fashioned corsets.

“They work along the same lines,” said Dr. Apovian. “Both pose health risks in terms of constricting organs and bones too tightly. Neither will help to achieve weight loss.”

And much like traditional corsetry, modern-day waist training can damage your body, as the good doctor warns. There are internal organs, after all, that take up space and can’t be willed out of existence.

“Waist trainers come with health risks if worn too tightly or too often,” said Dr. Apovian. “They can push the stomach beyond the diaphragm, causing reflux. They can also interfere with breathing.”

Physicians are also concerned about the negative effects of prolonged waist training on the spine, colon, liver, stomach, and small intestines. A slim waist might look sexy but organ damage is definitely unattractive.

Even if you believe that beauty is pain, and that a Kardashian’s body would be worth an adverse health outcome or two, waist training will not permanently reshape your figure. Promises of permanent slimming are simply not grounded in fact.

“Wearing a waist-trainer will make the wearer appear thinner temporarily,” Dr. Apovian noted, “but there is no reason to believe that it would help to achieve permanent weight loss.”

Medical experts have repeatedly warned that waist training is neither safe nor effective, but the trend continues unabated. And while waist shapers don’t work, the advertising for them certainly does. As Teen Vogue reported, there are hundreds of thousands of photos tagged with #WaistTraining on Instagram.

“Lost two inches in two weeks,” social media personality Salice Rose recently claimed, sporting a leopard-print shaper.

“If you want to lose four inches off your waste, get you one,” reality star Cardi B. wrote in the caption to her waist training video, posted this Wednesday. “I wear mine six hours daily, it’s not uncomfortable.

“It’s either you exercise or you waist train, bitch,” Cardi B. advises at the end of her video.

In the comments section of her video, one user wrote: “we need to waist train f*ck the gym lol.”

But sadly, there is no substitute for exercise and no shortcut to a body shape that is probably unattainable anyway.

“I would recommend diet, exercise, and sleep,” said Dr. Apovian, when The Daily Beast asked how one could shed inches without squishing internal organs together. “This is the best method for healthy permanent weight loss.”

One of the only things a tummy-cinching might be good for would be to briefly visualize the potential results of diet and exercise. Dr. Apovian told The Daily Beast that it would probably be fine to wear a waist trainer “occasionally” without tightening it too much.

“It may even work as a motivation to change eating, exercising, and lifestyle habits,” she said. “But no one should believe that it will cause weight loss on its own, and if any discomfort is felt, the waist trainer needs to be loosened—or abandoned—immediately.”