Millions wrongly branded too fat by ‘f lawed’ BMI
MILLIONS of adults are wrongly being told they are too fat because of misleading BMI calculations, researchers claim.
Body mass index does not accurately measure whether someone is carrying excess weight or if they are more likely to die, a study found.
Academics also pointed out that many ‘slim’ adults whose BMI is in the normal range are carrying unhealthy amounts of fat without realising it.
The findings are further evidence that the measurement used by the NHS and schools is an unreliable and blunt tool.
BMI is meant to show whether someone is underweight, normal, overweight or obese by comparing their weight to their height.
But it does not distinguish muscle from fat, which means well-built athletes such as rugby players are classified as obese.
The method is also flawed for children, even though it is used in schools to measure pupils as part of an NHS monitoring scheme.
Many parents of slim youngsters have been sent letters from school nurses branding their children overweight.
Last month, mother Samantha Stroud, 29, received a letter explaining that her four-year-old daughter Honey-Rose was over- weight and should be put on a diet. Mrs Stroud, who has a relative with anorexia, said labelling children based on their weight at such a young age could trigger eating disorders.
Honey-Rose was weighed at her primary school in Devon as part of the NHS’s child measurement programme.
At 3ft 4in tall and weighing just under 3st, she had a BMI in the 94th centile for her age.
In the latest study Dr William Leslie, of the University of Manitoba in Canada, compared the records of almost 50,500 middleaged adults – some of whom had since died – including their BMIs and body fat percentages.
Body fat percentage – the proportion of your body which is comprised of fat tissue – is trick- ier to work out than BMI and usually requires a scan.
In the study, an X-ray was used to measure fat levels around the adults’ spines and hips, taking this to be an average of the entire fat around the body.
Dr Leslie found that the two groups most likely to have died had either a low BMI or a high body fat percentage. By comparison, those with a high BMI – classified as overweight or obese – were generally in relatively good health and often very fit.
Dr Leslie, whose study is published in the Annals of Internal Medicine, said: ‘The simple messaging that we’re all too fat and should be thinner is based on BMI. It’s an oversimplification of a more complex story.
‘I’m not saying BMI isn’t helpful, clearly it is. But it’s a crude measure and body composition is not accurately captured by BMI alone.
‘ To say someone i s obese implies that they have too much fat. BMI may misclassify some people as having excess fat, which isn’t the case.’
He added that some adults with normal BMIs have hidden fat stored around their organs, which is extremely harmful.
In the UK, around 60 per cent of adults and roughly a third of children are either overweight or obese according to their BMI.
In January, researchers from the University of California, Los Angeles called for BMI to be scrapped, claiming it was wrongly giving adults a ‘death sentence’.