A team of international experts is advocating for a fresh approach to define and diagnose obesity, shifting the focus away from the debated body mass index (BMI) method. Their intention is to enhance the identification of individuals who truly require treatment for obesity, which is caused by surplus body fat.
In a report released recently, it is suggested that the definition of obesity should not just rely on BMI—a calculation based solely on height and weight—but should also incorporate additional metrics, such as waist circumference and indications of health complications linked to excess weight.
Obesity is estimated to impact over a billion individuals around the globe, with approximately 40% of adults in the United States being classified as obese according to the Centers for Disease Control and Prevention.
Dr. David Cummings, an obesity specialist from the University of Washington and one of the 58 contributors to the report published in The Lancet Diabetes & Endocrinology, stated, “The whole goal of this is to get a more precise definition so that we are targeting the people who actually need the help most.”
The document introduces two new classifications: clinical obesity and pre-clinical obesity. Individuals identified with clinical obesity will meet the BMI criteria and other obesity indicators, alongside demonstrating health complications that can arise from excess weight. These complications might include conditions such as heart disease, hypertension, liver or kidney issues, or chronic severe pain in the knees and hips. These individuals would be eligible for various treatments, encompassing dietary and fitness regimes as well as obesity medications.
On the other hand, those categorized with pre-clinical obesity do not currently exhibit any ongoing health problems but are considered at risk for developing such issues.
BMI has been criticized for its inaccuracies, as it can lead to both overdiagnosis and underdiagnosis of obesity. Traditionally, a BMI of 30 or higher defines obesity; however, not everyone with excess body fat will have a BMI that exceeds this threshold. Athletes or individuals with high muscle mass may possess a high BMI while maintaining a healthy fat percentage.
Preliminary assessments indicate that approximately 20% of individuals previously classified as obese would no longer fit this definition under the new guidelines. Conversely, around 20% of those who suffer from severe health consequences but have a lower BMI would now be recognized as clinically obese, according to the experts.
Cummings emphasized that while this change would not drastically alter the overall obesity statistics, it would significantly enhance the accuracy in diagnosing those truly experiencing clinically significant excess fat.
The new definitions have garnered backing from over 75 medical organizations globally; however, the speed and extent of their adoption in medical practice remain uncertain. The report indicates that implementing these recommendations “will carry significant costs and workforce implications.”
A representative from the health insurance group AHIP remarked that it’s premature to predict how insurance plans will integrate these new criteria into their coverage or policies.
Dr. Katherine Saunders, a specialist in obesity at Weill Cornell Medicine and co-founder of the obesity treatment firm FlyteHealth, pointed out that while measuring waist circumference seems straightforward, the application can be inconsistent. Many healthcare professionals may not be adequately trained in this measurement, and standard medical tape may not accommodate individuals with obesity.
Moreover, distinguishing between clinical and pre-clinical obesity would necessitate a thorough health evaluation and relevant laboratory tests, she added.
“For a new classification system to gain widespread acceptance, it must be extremely fast, cost-effective, and reliable,” she stated.
Kate Bauer, a nutrition authority at the University of Michigan School of Public Health, suggested that the new classifications could lead to misunderstanding among the public. “The public likes and needs simple messages. I don’t think this differentiation is going to change anything,” she remarked.
Dr. Robert Kushner, an obesity expert at Northwestern Feinberg School of Medicine and co-author of the report, acknowledged that transforming the definition of obesity will require time. “This is the first step in the process,” he noted. “I think it’s going to begin the conversation.”
