New definition of obesity challenges current use of BMI

Obesity should be assessed in a way that goes beyond the standard measurement of body mass index, or BMI, according to a new definition of the disease released by an international commission.

His report, published Tuesday in the journal The Lancet Diabetes & Endocrinology, argues for the need to focus on a person’s amount of body fat and medical complications, not just their weight.

If the guidelines are widely adopted, they could change doctors’ perceptions of who should be treated for obesity. They could also affect the use of prescription drugs that treat obesity, such as Wegovy and Zepbound. The new definition of obesity has been endorsed by 76 organizations around the world.

The commission proposed that instead of continuing to use BMI as a way to define obesity, it should be a screening tool to determine who should be tested for excess body fat.

The commission said people with a BMI above 25 and too much fat, but who are otherwise healthy, should be left alone. They must be monitored and advised to stop gaining weight and possibly lose it.

Their condition would be called preclinical obesity.

Other people suffering from one of 18 medical conditions caused by obesity – 13 among children and adolescents – need medical treatment to improve their health and prevent serious organ injury. Conditions include shortness of breath, heart failure, hip or knee pain, metabolic abnormalities, and poor organ function.