Number of those accepting that they are very overweight has dropped, raising fears that key health messages will be ignored

Fewer than one in 10 people who are obese would ever describe themselves as such, according to research showing that most people with a weight problem seriously underestimate it.

Being overweight and obese have become so common that perceptions have shifted, suggest the authors of a paper in the journal BMJ Open. Many obese people who are in danger of health problems associated with their weight, including heart attacks, stroke, cancer and diabetes, think their weight is normal or only slightly too much.

A team funded by Cancer Research UK compared people’s perceptions of their weight in 2007 and again in 2012. They asked over 650 survey respondents whose height and weight gave them a BMI (body mass index) of 30 or more, which is defined as obese, to indicate how they would describe their own weight. In 2007, only 13% of women and 4% of men considered themselves to be obese, and in 2012 that dropped to 11% and 7%.

The researchers wanted to know whether publicity about obesity in recent years had resulted in greater self-knowledge among those who are overweight. Because the number of those acknowledging they were obese was so small – and because there is a stigma around the word – they then added those who said they were “very overweight”.

They found the number of women prepared to call themselves either obese or very overweight did not go up – in fact, it substantially dropped from half (50%) in 2007 to a third (34%) in 2012.

Fewer men admitted to being obese or very overweight and this number did not shift significantly in the five years – from 27% in 2007 to 23% in 2012.

Professor Jane Wardle, one of the authors and director of the Cancer Research UK health behaviour centre at University College London, said: “It’s a real worry that people don’t recognise that their weight places them in the obese category, because it means they aren’t aware they are at increased risk of a number of health problems, including cancer.

“This is despite increased media coverage of obesity, and public health campaigns aimed at improving public awareness.

“The term obese is often considered derogatory, which may be why so many people reject it. Mass media often illustrate obesity in a way that people find offensive, with pictures of bulging beer bellies and huge behinds, so people shy away from these images.

“But we also asked people whether they felt they were “very overweight” and the majority of those who were obese did not accept this term either. This is a real problem, as it means they are unlikely to identify with health messages on the subject of weight.

“We need to establish better ways for health professionals to address this sensitive subject and communicate with people whose health would benefit from positive lifestyle changes.”

Two-thirds of the population of the UK are overweight and around a quarter are obese. The paper suggests there is: “Substantial continuing resistance among the obese population in Britain to identifying themselves as obese.” It notes that there was a substantial decrease in the number of women prepared to say they were even “very overweight” between 2007 and 2012, which suggests “weight misperception” rather than rejection of the stigmatising term obese.

“The trend towards normalisation of a body size in the obese range appears to be continuing, at least among women,” it says. There is a need to counter people’s assumption that obesity is an extreme state, they say.