In one of the first studies of its kind to examine British perceptions of obesity, fewer than 10% of those who are clinically obese accept they have a serious weight problem.
In a survey of some 2,000 adults, only 11% of obese women accurately acknowledged they were “obese”, with most describing themselves as “very overweight” or “just right”.
And among men, only 7% correctly described themselves as being “obese” and another 16% as “very overweight”.
About 10% of people in the survey knew the BMI threshold for obesity and those who did were more likely to define themselves as “obese”.
Researchers suggest that as bigger sizes become the new “normal”, people are less likely to recognise the health problems associated with their weight.
Professor Jane Wardle, co-author and director of the Cancer Research UK Health Behaviour Centre at UCL, 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.
She said that people were asked if 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.”
Around 18,000 cases of cancer in the UK each year are linked to being overweight or obese. Excess weight is known to increase the risk of several types of cancer including cancers of the breast in post-menopausal women, bowel, womb, oesophagus, pancreas, kidney and gallbladder.