An international group of 58 experts has called for a major shift in the way obesity is diagnosed, arguing that the current reliance on body mass index (BMI) is outdated and insufficient. In a proposal published January 14 in The Lancet Diabetes & Endocrinology, the experts, from fields including obesity medicine, endocrinology, and bariatric surgery, suggest that BMI should be augmented or replaced by more comprehensive body measurements, such as waist circumference or tests that measure body fat more accurately.
BMI, a widely-used tool to assess obesity by comparing weight to height, has long been criticized for its inability to distinguish between fat and muscle. Furthermore, it does not take into account the diversity of body types and fails to reflect a person’s overall health. This, according to the experts, necessitates a more nuanced approach to diagnosing and treating obesity.
The group has also proposed dividing obesity into two categories: clinical and preclinical. Clinical obesity is characterized by health issues such as impaired organ function or reduced mobility, while preclinical obesity refers to individuals who have excess body fat but no immediate health problems. Dr. Francesco Rubino, chair of metabolic and bariatric surgery at King’s College London, called this proposal “the most radical change” in obesity diagnosis. He stressed that this approach is objective and globally applicable, aiming to distinguish between people who need urgent treatment and those who may benefit from monitoring.
While clinicians are not required to adopt the new framework, the proposal has been endorsed by 76 medical organizations, including the American Heart Association and the World Obesity Federation. Dr. Sahar Takkouche, an obesity-medicine specialist at Vanderbilt University, called the proposal “new hope for more effective care,” though she noted challenges, including the limited availability of body composition machines in doctor’s offices and outdated insurance policies.
This new approach could help clinicians identify patients who would benefit from treatments like weight-loss drugs or surgery, as opposed to those with preclinical obesity who may not need intensive interventions. Dr. Rubino highlighted the importance of recognizing that obesity is a spectrum, not a singular condition.
Despite the momentum for change, the proposal has sparked debate. Dr. Lisa Erlanger, president of the Association for Weight and Size Inclusive Medicine, criticized the proposal for assuming that all excess body fat is inherently tied to illness. She argued that the medical community often fails to explore whether obesity truly causes the health problems it is linked to and whether weight loss is the best solution for all patients.
As the medical field continues to grapple with the complexities of obesity, experts like Dr. Rubino argue that it’s crucial to develop more accurate and tailored methods of diagnosis that reflect the true health impacts of obesity. “Disease should not be a matter of opinion,” he said, “it should be a matter of fact.”
