They come every year around this time, as reliably as the chilling of the air and the preponderance of red coffee cups: the public-relations pitches, bedecked in exclamation points and cheer, offering expert tips on how to fight the holiday weight, or win the battle of the bulge, or stay svelte through New Year’s. If I had a nickel for every email in my inbox right now exhorting me to put down the pie, I’d have enough money to buy myself several more pies. Not the grocery-store brand, either. The fancy bakery kind.

‘Tis the season, in other words, to make some strangers feel bad about their bodies. Over the weekend, some people in London, purportedly from a group called Overweight Haters Ltd., took that to heart:

Kara Florish, an employee of the U.K.’s National Health Service, tweeted on Saturday that someone had handed her the card while she was riding the London Underground.

Here’s the back:

According to the BBC, London Transport is encouraging any riders who see the cards being distributed to notify the police.

There are many, many reasons why this is gross. An easier and more productive exercise than engaging with those reasons may be to point out why it’s also misguided. Research has shown that fat-shaming doesn’t actually work—as far as strategies to curb obesity go, it’s ineffective at best, and downright counterproductive at worst.

Last year, a survey tracking 3,000 people in the U.K. found that those who reported weight discrimination gained an average of two pounds over the study’s four-year window; those who hadn’t experienced weight discrimination lost an average of a pound and a half over the same time period. A similar study out of the Florida College of Medicine, published in 2013, also tracked people over four years, and found that people who reported weight discrimination at the beginning of the study were 2.5 times more likely to be obese by the end of it. And in 2012, researchers from Yale University found that people rated anti-obesity campaigns with negative or accusatory messages as less motivating than ones with more neutral slogans, like “Let’s Move.”

“The most positively rated were campaigns that focused on encouraging specific health behaviors or actions, like eating fruits and vegetables every day or engaging in physical activity,” the Yale study’s lead author, Rebecca Puhl, told The Atlantic at the time. “And the most motivating were the ones that made no mention of obesity or weight at all.”

Nevertheless, the idea of social ostracism as an effective weight-loss tool remains a pervasive one, even among some health researchers. In 2013, the bioethicist Daniel Callahan published an editorial in the journal The Hastings Center Report calling for “stigmatization lite,” a sort of mild shaming campaign to pressure overweight people into slimming down.

Shortly thereafter, the same journal published a collection of letters from psychologists around the country calling Callahan’s idea “a failed and ethically dubious strategy” and “a burden of social change [placed] on individuals already at society’s margins.” As one letter put it, “if shaming reduced obesity, there would be no fat people.”

Anecdotal evidence suggests this is true in a wide variety of contexts. After all, if shaming worked, there'd be no jerks handing out those cards on the subway, either.