Obesity diagnosis requires radical rethink, say experts

People are being "overdiagnosed" with obesity, leading medics have warned as they called for a "reframing" of the way the condition is diagnosed. Academics have suggested that a body mass index (BMI) score is not “nuanced" enough to measure obesity and more assessments are needed before someone is told they are obese.

- ELLA PICKOVER

Solely using BMI can lead to both overestimates and underestimates of the number of obese people, they said. For instance, some people may be very active and have no ill-effects of their weight but are still classified as obese.

Meanwhile, others may be suffering significant harm because of obesity, such as problems with their internal organs. A new Lancet Commission – made up of more than 50 experts from around the world – said that a “radical overhaul” is needed in the diagnosis of obesity.

They said that “BMI useful but we need to go beyond BMI to determine excess body fat” and that the measurement tool should be used only as a “surrogate measure of health risk”.

And obesity should only be diagnosed using BMI when clinicians also take other measurements such as waist to hip ratio or waist to height ratio.

Ideally, obesity would be measured using total body fat, but the academics conceded that this would involve clinics “going beyond” what they would usually do to identify obese people because it can include more expensive and time-consuming body scans.

Researchers called for two new “diagnostic categories” of obesity. These are:

– Clinical obesity – defined as a “chronic systematic illness” whereby excess fat can lead to organ damage and cause “lifealtering and potentially life-threatening complications”.