Discriminating against people because of their weight may only increase their likelihood of gaining more weight, new study shows.
The researchers found that among people who were not obese, those who reported experiencing weight discrimination were 2.5 times more likely to have become obese four years later.
Among people who were obese at the start of the study, those who experienced discrimination were three times more likely to remain obese, compared with those who did not feel discriminated against, the study found.
The results suggest weight discrimination feeds a vicious cycle, in which people who are overweight or obese are likely to experience weight discrimination, which in turn leads to obesity and difficulties with weight management, according to the study, which was published July 24 in the journal PLOS ONE.
"Weight discrimination is relatively common," said study researcher Angelina Sutin, professor of psychology at Florida State University College of Medicine. "But the findings suggest that shaming has the opposite effect that people often think."
Previous research shows that experiencing weight bias may lead to depression, low self-esteem and other poor psychological outcomes. In the new study, the researchers didn't test the mechanisms that might be driving the link between discrimination and obesity, but they said they suspect that people who experience weight discrimination are more likely to develop unhealthy behaviors as coping strategies, including binge eating and avoiding physical activity. [11 Surprising Things That Make Us Gain Weight]
Nevertheless, weight bias is one of the most socially accepted forms of discrimination, the researchers said, perhaps justified by the misconception that such discrimination may motivate people to lose weight.
"What's really striking in the study is that not only does weight discrimination increase the risk of obesity, but it's also related to remaining obese over time," said Rebecca Puhl, deputy director at the Rudd Center for Food Policy & Obesity at Yale University. Puhl was not involved in the study.
"In our efforts to address obesity, we need to recognize that stigma poses legitimate barriers and challenges in those efforts," Puhl said.
In recent years, there have been hundreds of anti-obesity campaigns emerging from public health organizations, Puhl said. While many of them stem from positive intentions to improve public health, some are being criticized for shaming and blaming people who are affected by obesity.
"We need to recognize that that's not an effective way to communicate to the public about weight and health," Puhl said.
Puhl and her colleagues have previously studied public reactions to obesity campaigns. They found that campaigns that seemed to resonate the most with the public were those that focused on specific health behaviors that everyone, regardless of their body size, is encourage to follow — for example, eating more fruits and vegetables, and replacing sugar- and cream-based beverages with water.
"Interestingly, the campaigns that received the most favorable ratings were the ones that didn't even mention obesity," Puhl said.
In the new study, the researchers looked at the heights and weights of more than 6,000 participants, measured in 2006 and 2010.
Participants completed questionnaires that measured perceived discrimination — for example, whether they felt they were treated with less courtesy and respect than other people. Participants were also asked whether they thought those experiences happened to them because of characteristics including their gender, race and weight.
Discrimination based on other factors, such as sex or race, did not appear to have the same correlation with weight.
"There is a lot of evidence that experiencing weight discrimination is associated with increased risk of maladaptive eating patterns such as binge eating, emotional eating," Sutin said.
There may be direct physiological mechanisms too, she added. The stress caused by discrimination increases the cortisol hormone, which is associated with weight gain.
Sign up for the Live Science daily newsletter now
Get the world’s most fascinating discoveries delivered straight to your inbox.