Changes to BMI system could reclassify millions as 'obese'

Person upset with their BMI measurements
-Credit: (Image: GETTY)

New changes to the classic BMI measurement system are being called for by a coalition of experts from the European Association for the Study of Obesity. The proposed reform could see countless people currently labelled as a “healthy weight” reclassified as “obese” to tackle the “skinny fat” phenomenon.

The experts highlighted that the changes to the system used by the NHS would allow these people to get the obesity treatments they are currently missing out on but could benefit from. Specifically, the reform would focus on abdominal fat that wraps around vital organs.

This type of fat is also considered more dangerous for a person’s overall health and well-being than subcutaneous fat, which is more visible as it sits just beneath the skin. Abdominal fat has been linked to a higher risk of heart disease, diabetes, stroke, dementia and certain cancers.

Currently, people can have high levels of abdominal fat while also being well under the BMI threshold for obesity. The current BMI system takes a person’s weight and divides it by the square of their height.

The new framework would lower the threshold of the obesity label on the current system as well as take into account a waist-to-height ratio and the presence of weight-related complications like high blood pressure and diabetes. The proposed changes have been published in the Nature Medicine journal and notes: “The basis for this change is the recognition that BMI alone is insufficient as a diagnostic criterion, and that body fat distribution has a substantial effect on health.”

The changes hope to target a group of countless Brits currently classified as healthy but “reducing the risk of undertreatment in this particular group of patients in comparison to the current BMI-based definition of obesity”.

It also highlighted that the BMI index doesn’t indicate the “severity of the disease” in patients and critiqued the clinical processes and management of obesity after diagnosis in comparison to other chronic diseases, with the recommended changes also incorporating personalised therapeutic targets.

The coalition noted that companies and organisations may want to use the new framework such as the NHS, which currently uses BMI as a criteria for patients to access some obesity medications such as Semaglutide, the active ingredient in the likes of Wegovy.

This isn’t the first time the BMI system has been urged to be overhauled as doctors have relied on the same measurements for almost two centuries. One of the biggest issues experts have with BMI is that it’s incapable of differentiating between fat and muscle mass.

For example, a fit rugby player with plenty of muscle and someone who is overweight with a sedentary might share the same height and weight measurements, despite differing physiques. Therefore both could be classed as obese under the current BMI equation.