Medical experts proposed a radical overhaul of how
The recommendation signals a long-awaited shift from a single imperfect metric toward a more personalized diagnosis that takes into account a person's ability to accomplish everyday tasks and the
The Lancet Diabetes and Endocrinology Commission, consisting of experts from around the world, put forward the new definition for obesity. It was endorsed by 76 organizations including the World Obesity Federation, the American Heart Association and Britain's Royal College of Physicians.
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"The commission is re-framing obesity and acknowledges the nuanced reality of obesity," said Robert Eckel, emeritus professor of medicine at the University of Colorado Anschutz Medical Campus and one of the group's members.
The body mass index, a weight-to-height ratio, has long been criticized as too simplistic, in part because it can't distinguish between fat and muscle mass. Currently, anyone with a BMI of 30 or more is considered obese, regardless of their body composition or general fitness.
The commission is "laying bare the flawed assumption that body mass for size is, by itself, a marker of health," said Adam Collins, an associate professor of nutrition at the University of Surrey who wasn't involved in the work.
Pharma Impact
A new generation of obesity drugs like Novo Nordisk A/S's Wegovy and Eli Lilly & Co's Zepbound is changing the perception of obesity as a multi-faceted illness that requires medical intervention rather than greater willpower, ushering a revolution with ripple effects from food manufacturing to medical insurance.
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The new framework could help clinicians determine whether a patient needs medicines or just monitoring and general health advice.
The next step would be for country-level guidelines on obesity to be updated to reflect the new recommendations. It's unclear whether or when that might happen.
But under a new set of rules, some patients who were previously considered obese may no longer qualify for treatment with drugs like Wegovy and Zepbound, at least at first, until regulators decide whether pre-clinical obesity also requires prescription medicines.
Heart and Lungs
BMI is more useful on a population level rather than an individual one, according to Francesco Rubino, commission chair and head of metabolic and bariatric surgery at King's College London.
"BMI contains no information about the functioning of organs," he said. "For instance, how well is the heart functioning? Are the lungs doing their job as normal?"
Under the new guidelines, patients whose BMI previously classed them as obese should get checked for excess fat with tools such as waist circumference or waist-to-hip ratio. If they have excess fat, the doctor should look for signs of organ dysfunction or limitations in day-to-day activities.
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A person will only be considered as clinically obese if those last measurements are also positive. Otherwise they will be classed as having pre-clinical obesity.
The new benchmark should be included in clinical-practice guidelines and in the training of health-care workers, according to the Lancet commission. It applies to adults regardless of age, gender or ethnicity, said the University of Colorado's Eckel.
Wegovy and Zepbound are currently approved in the US for anyone with a BMI of 30 or more. The threshold is 27 for individuals with a weight-related condition like high blood pressure or sleep apnea.
Drugmakers are also increasingly looking at the importance of body composition, with companies trying to create therapies that help people keep muscle even as they shed fat.
