New research suggests a BMI of 27 is obese, but that’s still not accurate enough, says expert

Controversial new research measuring body fat levels has concluded a lower BMI of 27 is more accurate than 30 to determine obesity.

 A new Italian study has found that measuring body fat levels rather than our body mass index (BMI) gives a truer picture of who is obese.

Currently, a BMI of up to 25 for an adult is considered healthy, while up to 29 is overweight, and 30 or above is considered obese. However, the researchers found this does not take into account changes in body composition, where we lose muscle and gain fat as we get older, leading to considerably more body fat with no gain in weight.

 To allow for this shift, the study, published originally in the journal Nutrients but recently presented at the European Congress on Obesity, found that a BMI of 27 should be used to define obesity in future.

The study, led by researchers at the University of Tor Vergata in Rome, set out to challenge the traditional BMI measure of 30 to determine obesity, which is currently accepted in most countries and supported by the World Health Organisation (WHO).

The researchers said: “Due to changes in body composition that occur across the lifespan, with an increase in body fat and a decrease in lean mass, we aimed to test the validity of this BMI cutoff point.

“In a real-world clinical setting, a new BMI cutoff point (BMI = 27.27 kg/m2) has been identified for predicting obesity in middle-aged and older adults and obesity guidelines should be revised accordingly.”

 However, a leading expert says that simply using a broad body fat measure, even one more accurate than the traditional BMI reading, still does not give a true picture of the stress on people’s hearts or their overall health in relation to their weight.

Dr Avinash Hari Narayanan (MBChB), Clinical Lead at London Medical Laboratory, said: “It’s certainly high time that a more meaningful instant snapshot of how our weight might be impacting our health was introduced.

“Today, a simple and quick finger-prick blood test can swiftly analyse some of the most important risks to our heart health. One rapid test will measure the risk of high cholesterol, diabetes and generalised inflammation, which all dramatically increase the potential of future heart attacks.

“Obviously, there is still a need for a BMI test as a general indicator that our weight may be impacting our health. However, with the arrival of new blood testing technology, BMI ought to be taken as a reading in conjunction with a heart health test.”