BMI wrongly branding people as unhealthy, new research reveals

Almost half of people diagnosed as obese using Body Mass Index measurements are actually healthy, according to new research.

Scientists claim the BMI assessment is wrongly branding millions of people unhealthy when many are in fact much fitter than their 'slim' counterparts.

Psychologist Professor Janet Tomiyama, of the University of California, Los Angeles, said: "Many people see obesity as a death sentence. But the data show there are tens of millions of people who are overweight and obese and are perfectly healthy."

It says BMI is being used by healthcare companies to increase premiums in some countries.

Scientists predicted the latest findings will be "the final nail in the coffin for BMI."

With obesity levels spiralling, the concern is it is not an accurate predictor of future health. People can be at risk of disease, and yet have a normal BMI, which gives them false hope.

Yet many companies are using their employees' BMIs as a factor in determining workers' health care costs. And people with higher BMIs could soon have t

o pay higher health insurance premiums in the US, if a rule proposed in April by the Equal Employment Opportunity Commission is adopted.

Prof Tomiyama and colleagues found using BMI to gauge health incorrectly labels more than 54 million Americans as "unhealthy," even though they are not.

The study, published in the International Journal of Obesity, analysed the link between BMI and several health markers, including blood pressure and glucose, cholesterol and triglyceride levels, using data from the most recent National Health and Nutrition Examination Survey.

It showed almost half of Americans who are labelled 'overweight' by virtue of their BMIs (47.4 percent, or 34.4 million people) are healthy, as are 19.8 million who are considered 'obese'.

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Prof Tomiyama said given their health readings other than BMI, the people in both of those groups would be unlikely to incur higher medical expenses, and it would be unfair to charge them more for health care premiums.

The analysis also found more than 30 per cent of those with BMIs in the 'normal' range, about 20.7 million people, are actually unhealthy based on their other health data.

And more than two million people who are considered 'very obese' by virtue of having a BMI of 35 or above are actually healthy. That is about one in seven (15 percent) Americans who come into this category.

In previous research Prof Tomiyama found there was no clear link between weight loss and health improvements related to high blood pressure, diabetes and cholesterol and blood glucose levels. She was surprised at the magnitude of the numbers in her latest study.

She said: "There are healthy people who could be penalized based on a faulty health measure, while the unhealthy people of normal weight will fly under the radar and will not get charged more for their health insurance. Employers, policy makers and insurance companies should focus on actual health markers."

Another of the researcher Jeffrey Hunger, a doctoral candidate at the University of California, Santa Barbara, said it shows BMI is a deeply flawed measure of health.

He added: "This should be the final nail in the coffin for BMI."

Mr Hunger recommends people focus on eating a healthy diet and exercising regularly, rather than obsessing about their weight, and strongly opposes stigmatizing people who are overweight.

The proposed EEOC rule would allow employers to charge higher insurance rates to people whose BMI is 25 or higher.

A BMI between 18.5 and 24.9 is considered normal, but the study emphasizes normal BMI should not be the primary goal for maintaining good health.

Prof Tomiyama is planning a new study of people with high BMIs who are very healthy, and prospective participants may contact her laboratory for more information.

BMI is the most widely used method for assessing whether people are a healthy weight.

It is worked out by dividing weight in kilograms by height in metres, and dividing the answer by height again.

Typically, a BMI below 18.5 is regarded as underweight, 25 or over is 'overweight' and 30 or more is categorised as 'obese'.

The average BMI for a man in the UK is 27 and for a woman 26.9 which means many of us are officially overweight and at risk of diabetes and heart disease

BMI, which was first used in 1832, is now entrenched in healthcare, used for diagnosing anorexia, for instance, and to calculate life assurance premiums.

It is also key to official guidelines for treatment - for example, who qualifies for gastric surgery on the NHS. One in four British adults are classified as obese using BMI.