In May of this year, Playboy model Dani Mathers was sentenced to 30 days of community labor and three years of probation for Snapchatting an image of a nude woman in her L.A. Fitness locker room with the caption, “If I can’t unsee this then you can’t either.” In June, bloggers attacked Rihanna for posting photos to Instagram in which she appeared to have gained weight. And in July, singer Kelly Clarkson received comments critical of her body, including “You’re fat,” in response to a benign tweet about Independence Day.

These are just a few of the more publicized examples of body-shaming. These shamers, often enabled and encouraged by the anonymity of the internet, are spreading toxic sentiments in ways both blatant and subtle.

Efforts to track the growth of body-shaming are relatively recent and not definitive. But researchers in the fields of psychology and sociology have long suspected that the mental and emotional impact of body-shaming is real — and UCLA’s Janet Tomiyama, one of the leading researchers in the field, is working to quantify it.

Tomiyama runs the university’s Dieting, Stress and Health (DiSH) Lab, which studies “the intersection between eating, not eating (dieting), stress and health.” As DiSH’s lab director and an associate professor in UCLA's department of psychology, Tomiyama has been examining the effects of fat-shaming and body-related stigma for six years.

“There is this notion that body-shaming is somehow going to motivate people to lose weight,” she says. “But from a purely scientific point of view, experiencing weight stigma could actually make you gain weight.

“To me,” she adds, “that’s really alarming.”

A study she co-authored, published in Obesity in 2015, was “the first study to examine physiological consequences of active interpersonal exposure to weight stigma.” Her research has been covered by The New York Times, Time and the Los Angeles Times, among others, and the Association for Psychological Science named her a “Rising Star” for her groundbreaking investigations.

Much of the foundation for Tomiyama’s research is the pre-existing beliefs held by Americans about overweight people.

“There are certain top-hitting stereotypes that are associated with being overweight,” she says. “Lazy, gluttonous, stupid, worthless — those are the top words. Society is incredibly mean to people it perceives as heavy.”

Tomiyama has zeroed in on three ways that weight stigma leads to weight gain. The first has to do with biology. When a person becomes stressed, his or her body excretes the hormone cortisol. Cortisol has several jobs in the body, but one is to signal extra storage of fat in the belly — one of the most toxic types of body fat.

“If someone is experiencing stress because someone else is being mean to them because of their size,” Tomiyama says, “that could cause them to excrete cortisol, and that could lead to weight gain.”

The second has to do with comfort eating. When a person experiences emotional discomfort because they’ve been stigmatized or discriminated against, he or she may turn to food — typically, food that’s not particularly healthful. Plus, that person may be demotivated to exercise. “If someone’s made you feel bad because of how your body looks,” Tomiyama says, “do you really want to put on some Lululemon and go to the gym?”

Finally, stress causes a reduction in the quality of a person’s executive functioning, the high-level decisionmaking part of the brain that engages in selecting rational choices over emotional choices, such as choices about what to eat (or choosing not to eat) at a particular moment.

“Human beings are built to eat,” Tomiyama says. “To not eat is an incredibly difficult, all-consuming activity. It requires the highest levels of executive control. And when somebody is stressed, that’s the first part of the brain that gets dampened down.”

It’s worth noting that fat-shaming isn’t always directed at a person’s appearance. “There is a sort of politically correct, conventional way that people can express their hatred of heavy people, which is the health angle,” Tomiyama says.

In those instances, fat-shaming is expressed as a concern for a person’s well-being. But according to Tomiyama, there is little research supporting the idea that being overweight, in and of itself, makes a person unwell.

“If you drill down into the science of it,” she says, “it’s not really the case that fat is necessarily unhealthy.”

Tomiyama is a staunch supporter of the body-positive movement that’s emerging on social media. Models, celebrities and public figures are sharing photos of themselves at all shapes and sizes with hashtags such as #EffYourBeautyStandards, #HonorMyCurves and #BodyPositive. The pics haven’t been retouched, and they create communities for those whose physiques don’t conform to unattainable mainstream standards of extreme thinness.

“The one thing that gives me pause is messages like, ‘Big is beautiful,’ or ‘Heavier bodies are so beautiful,’ because the thing that’s of value in that situation is still beauty; it’s still visual,” she says. “You have no idea if they are a nice person or a smart person, which are the things we should be valuing.”

Shaming — for any reason — shouldn’t be an acceptable societal practice, Tomiyama says. “The real answer is, we shouldn’t be mean to anyone.”

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