The study is one of many which have suggested different cut-off points for BMI over the years.

Yet it’s unlikely BMI will be ditched anytime soon – it’s certainly much cheaper than scanning people to quantify their body fat accurately.

The researchers admit larger studies in other countries are needed to confirm the results. This study only looked at adults in one region of Italy and didn’t look at the distribution of fat in people’s bodies – only the percentage of the body made up of fat.

It also didn’t ask people about their diets or exercise habits to work how why some people might be more at risk from obesity than others.

On its own, it’s not clear whether body fat analysis would be a definitive measurement either.

“We need a simple tool to screen for obesity that can be available for anyone,” said co-author Prof Marwan El Ghoch, from the University of Modena and Reggio Emilia.

Prof Naveed Sattar, from the University of Glasgow, said: “Rather than cutting the obesity thresholds to 27, which would mean around half the adults in UK are living with obesity, other definitions of obesity that include also looking at waist circumference, combined with specific signs and symptoms of excess weight, are likely to be more informative.”

The search for the right tool continues.