Could YOU be ‘fat’ and not realize it? Experts propose a shake-up of BMI rules that would reclassify the average person over 40 as obese

Millions of Britons could be labeled as obese following a proposed major shake-up to the body mass index classification (BMI) system.

The weight-to-height ratio is supported by the World Health Organization and is used by doctors to determine whether a person is at risk for a variety of diseases such as diabetes, heart attacks and strokes due to excess fat.

Under the current system, a score of 18.5 to 25 is healthy. A score of 25 to 29 is considered overweight, and 30-plus means that someone is obese, the stage at which the risk of disease increases dramatically.

But now Italian research shows that the model for over-40s should be revised and anyone with a BMI of 27 or more should be classified as obese.

NHS data shows that only 26 percent of adults have a BMI of 30+.

But the average BMI of all adults over 40 in Britain ranges between 27.7 and 27.6, suggesting the majority would be declared obese and at risk under the proposed review.

It means that many people could theoretically be obese without realizing it.

Celebrities such as Avengers star Chris Hemsworth, Australian actress Rebel Wilson and British A-lister Tom Hardy would also technically fall into an ‘obese’ BMI under the changes.

Presenting their findings at the European Congress on Obesity in Venice, the authors of the new study said the current BMI cutoff for obesity may not be appropriate for middle-aged and older adults.

They said that bodies over 40 have increased fat accumulation around the waist, which, combined with age-related muscle loss, means there is no overall change in overall weight.

This means that despite the fact that the BMI system fails to raise the alarm and people do not realize that they are at risk of obesity-related health problems.

Researchers supported their findings with a survey of 4,800 Italian adults between the ages of 40 and 80, about equally divided between men and women.

Of this group, 38 percent and 41 percent of women had a BMI of 30 or more, which is obese according to current rules.

However, when the researchers used high-tech scans to measure their actual body fat percentage, 71 percent of men and 64 percent of women were rated as obese.

This meant that almost half of men and women with worrying fat levels were wrongly reassured by the BMI system.

When comparing the findings, they found that using a BMI cutoff of 27 for obesity instead affected almost 9 out of 10 obese patients detected with the body scan method.

Study author Professor Marwan El Ghoch, an expert in metabolic health at the University of Modena and Reggio Emilia, said: ‘This new BMI limit recognizes the physiological differences between middle-aged and older adults and younger population groups.’

Professor Antonino De Lorenzo, co-author and expert in biomedicine at the University of Rome, added: ‘If we continue to use the WHO standard for obesity screening, we will miss many middle-aged and older adults who are at risk of obesity-related diseases , including type 2 diabetes, heart disease and some cancers.

“Establishing this new BMI cut-point in clinical settings and obesity guidelines will benefit the potential health of millions of older adults.”

The research, presented at the conference, shows that their work has limitations.

For example, the study was conducted in one part of Italy, so the findings may not apply to other parts of the world.

Another was that they did not take into account other factors such as diet, exercise and sleep patterns, which could also influence obesity among participants, and not just age.

They called for similar studies on a larger scale in other parts of the world to confirm their results.

Experts have previously criticized BMI as a measure of health.

Created by a Belgian mathematician in the 1830s, doctors have relied on BMI for almost two centuries.

One downside is that it cannot distinguish between fat distribution and muscle mass.

Realistically, this means that a fit rugby player and a couch potato of the exact same height and weight share the same scores – even if the former has a ripped physique and the other has a spare tire.

This error would still apply under the suggested BMI of 27 is obese.

Hollywood hunk Chris Hemsworth, 40, who stars in the new Mad Max film, is said to be technically obese, based on the 6-foot-4 actor’s weight during his time as Thor in the Avengers series.

Fellow Australian actress Rebel Wilson, 44, who managed to reach her 4.4kg weight goal in a dramatic weight-loss journey, is said to be technically obese under the furor.

And Tom Hardy, 46, who weighed 14 pounds for his role as the villain Bane in the Batman film The Dark Knight Rises, would also be considered fat under the system change.

It is well known that obesity increases the risk of serious health problems that can damage the heart, such as high blood pressure, and cancer.

According to Cancer Research UK, being overweight is estimated to cause one in 20 cases of cancer in the UK.

Britain’s obesity crisis is also estimated to cost the country almost £100 billion a year.

This colossal figure includes both the health damage to the NHS and secondary economic impacts such as lost income as people take time off work due to illness and premature deaths.