Obesity is not a choice, and making people feel ashamed only results in feeling worse about themselves, says a report by leading psychologists.
He calls for language changes to reduce stigma, such as saying "an obese person" instead of an "obese person".
And he says that health professionals should be trained to talk about weight loss in a more supportive way.
The recent advertising campaign by a cancer charity has been criticized for "fat shame".
Obesity levels increased by 18% in England between 2005 and 2017 and in similar amounts in Scotland, Wales and Northern Ireland.
This means that just over one in four adults in the UK is obese while almost two thirds are overweight or obese.
But these increases cannot be explained by a sudden loss of motivation across the UK – it is much more complicated than that, according to the report by the British Psychological Society, which concludes that "it is not simply due to lack of will of an individual ".
Stress and trauma
"People most likely to have a healthy weight are those who have a high genetic risk of developing obesity and whose lives are also shaped by work, school, and social environments that promote overeating and inactivity," the document says.
"People living in deprived areas often experience high levels of stress, including major challenges and life trauma, their neighborhoods often offer few opportunities and incentives for physical activity and options for accessing healthy and affordable food are limited."
Psychological experiences also play an important role, the report says, with up to half of adults treated at obesity services struggling with childhood.
And the stress caused by fat shame – being made to feel bad about weight – by public health campaigns, family doctors, nurses and policy makers, often leads to increased diet and more weight gain.
Comedian James Corden recently spoke out against fat shame, saying, "If making fun of fat people made them lose weight, there would be no fat kids in schools."
Psychologists can use their knowledge to help train health professionals to better communicate about obesity, says Dr. Angel Chater, report author and reader of health psychology and behavior design at the University of Bedfordshire.
"If treatment for obesity were easy, we would not be here and would not have written this report," she says.
"You may have the best willpower in the world, but if you don't have access to the right food, the right environment, the best start in life … it will be difficult."
Learn to smoke
The government should address the problem of obesity in the same way as smoking, the report says.
Chief Executive of the British Society of Psychology, Sarb Bajwa, said: "He has been operating at all levels for decades, from government policy to helping smokers, but we are now seeing significant reductions in smoking and smoking problems. health it causes ".
"Psychologists have the scientific and clinical experience to help the health service do the same with obesity.
"We can help, not only by creating ways to help people, but also by advising public policies that will help create an environment in which people find it easier not to be obese in the first place."
However, psychologists are not in favor of obesity being classified as a "disease," because, they say, this could divert focus from behavioral changes that could succeed.