Obese people who lose weight will encounter far less social stigma and may even be seen as fitter than if they had been lean all along, but they may still face prejudice relating to how they lost weight, a new study suggests.

People who achieve a healthy weight through exercise and diet are seen more favourably than those who have had surgery, such as a gastric bypass, the study found.

In a paper published in the International Journal of Obesity, researchers from the UNSW School of Psychology - led by PhD student Jasmine Fardouly and supervised by Dr Lenny Vartanian – set out to study what impact weight loss has on social bias against obese people.

“It’s well-known that, as well as suffering adverse health, overweight and obese people are often stereotyped as lazy, incompetent and lacking self-control,” says Dr Vartanian. “Many obese people are motivated to lose weight to reduce that bias, but few studies have actually looked to see whether success in losing weight also succeeds in changing attitudes.”

Ms Fardouly says they found that those negative attitudes can indeed swing markedly the other way: “People tend to see an obese person who sheds a lot of weight as someone who eats more healthily, exercises more and is more competent and less sloppy.

“But that may be because people assume the weight loss was a result of better diet and more exercise. If they are told it was the result of surgery, our findings suggest they will view a previously obese person in some of the same ways as they did before – as someone who is lazy, lacks willpower and does not exercise enough.”

The study involved 73 psychology students being shown a photograph of an obese woman named Susan (not her real name), who had a body-mass index of almost 40 (much higher than a healthy BMI which is between 20 and 25). They were given Susan’s basic biographical information, asked to answer a series of questions about her lifestyle, and to rate her personality and behavioural traits.

Then they were then shown a more recent photograph - similar in clothes, facial expression and pose - after Susan had undergone a dramatic weight loss, down to a BMI of just 22. Some were told that she had used either surgery or diet and exercise, while others were given no explanation.

Regardless of the explanation given, the students generally rated Susan far more favourably for having lost weight. Even those given no explanation believed she was now eating more healthily and exercising more, and was more competent than before. But those who were told that the weight loss had been achieved through surgery judged her more negatively.

Weight-loss surgery patients may not be able to overcome the obesity stigma because surgery may be perceived as the lazy option, says Dr Vartanian.

People mistakenly believe that losing weight through surgery does not require the effort and discipline that losing weight through exercise and dieting does, the researchers say in the paper:  “Thus, despite choosing to undergo weight-loss surgery to better their health and reduce weight stigma, obese individuals may continue to be viewed as conforming to the obesity stereotype, and hence be considered lazy and lacking willpower.”

Media contacts: Dr Lenny Vartanian  l.vartanian@unsw.edu.au; Jasmine Fardouly   j.fardouly@unsw.edu.au