By Natalie Marchant
Millions of Britons are putting themselves at risk of early death by failing to recognise they are obese, a report suggests.
Obesity raises the risk of a number of potentially fatal illnesses including type 2 diabetes, heart disease, stroke and some types of cancer.
But research by Nuffield Health shows that many people mistakenly think they are merely overweight and not obese, not recognising the associated health risks.
The charity quizzed 3,100 people about their weight and wellbeing, including perceptions of their weight.
A 'clear misconception'
Half of those questioned thought themselves overweight and just 6% described themselves as obese.
However, body mass index (BMI) tests showed that 17% were clinically obese, with a BMI score over 30.
Another 3% registered a BMI of 40 or over, making them "morbidly obese".
The charity said there is a "clear misconception" over what weight is considered to be obese.
Dr Davina Deniszczyc, medical director for well-being at Nuffield Health, said: "There is a very big difference between being slightly overweight and clinical obesity.
"Once BMI reaches 30, the body experiences physiological changes which can put massive pressure on the vital organs - increasing the risk of numerous conditions including heart attack, stroke and liver disease.
People straying into dangerous territory
"We are seeing a vast number of people unwittingly straying into dangerous medical territory and perhaps not realising that the obesity awareness campaigns are directed at them.
"It's vital that people have the information they need in order to make informed decisions about their health."
If the data is extrapolated, this means that about six million Britons may be at risk by not recognising that they are obese and that they are at risk of the accompanying health risks, a Nuffield Health spokesman added.
The research also showed that eight out of 10 people polled were not aware of the relationship between obesity and cancers such as breast and bowel cancer.
Nearly half (46%) were not aware of the connection between obesity and stroke, and about two-thirds were unaware of an increased risk of liver disease or osteoarthritis.