An international commission of 56 obesity medicine experts has published a new definition and diagnostic criteria for obesity based upon nearly 3 years of study and discussion to reach consensus. Among their recommendations were new terminology – clinical and preclinical obesity – and alternate measures to replace the body mass index (BMI).
Clinicians have long critiqued the over-reliance on BMI measurements in obesity care, however, this marks the first international effort to promote evidence-based substitutes. The report was published last month in The Lancet Diabetes & Endocrinology.
MedCentral spoke to David Cummings, MD, FASMBS, a member of the commission and professor of medicine in the division of metabolism, endocrinology, and nutrition at the University of Washington, about the commission’s findings and what comes next. Dr. Cummings is based at the UW Medicine Diabetes Institute and the V.A. Puget Sound Health Care System, where he is the founding Director of the Weight Management Clinic and Program.
PROPOSED DIAGNOSTIC CRITERIA FOR OBESITY
The commission proposes new diagnostic criteria for clinical obesity, including both anthropometric and clinical components. Could you elaborate on the specific criteria used to distinguish clinical obesity from other forms of obesity?
Dr. Cummings: For people with a BMI between 25-40 kg/m², evaluating excess adiposity requires at least one additional anthropometric measurement beyond BMI (or two measurements if BMI is unavailable). Providers may choose from waist circumference, waist-to-hip ratio, or waist-to-height ratio, all of which have established gender-specific thresholds indicating excess adiposity. DEXA or other direct body fat measurements can replace these assessments. Individuals with BMI exceeding 40 kg/m² can be diagnosed with clinical obesity without additional measurements. Clinical obesity is defined by the presence of any illness directly resulting from excess adiposity, even without other obesity-related conditions. The commission has identified 18 such qualifying conditions for adults and 13 for children.
How do these criteria improve upon traditional methods of diagnosing obesity, such as using BMI alone, and what challenges might arise in implementing these in clinical practice?
Dr. Cummings: nitial findings indicate that widespread adoption of our clinical obesity definition would likely maintain similar overall prevalence rates compared to traditional BMI-only approaches. However, this refined definition would significantly improve identification of individuals who would derive the greatest benefit from obesity treatment interventions.
“[Our new definition of clinical obesity] would be much better at identifying individuals who would most benefit from interventions to treat that disease.”
HOW TO DISTINGUIDSH PRECLINICAL AND CLINICAL OBESITY?
What are the defining characteristics of preclinical obesity? Are there suggested strategies for monitoring and possibly intervening in individuals at this stage to prevent progression to clinical obesity or obesity-related disease?
Dr. Cummings: Preclinical obesity describes excess adiposity without current illness manifestations. This condition represents a risk factor for potential development of clinical obesity or related diseases. Individuals in this category should receive counseling on preventive interventions such as dietary changes and exercise to reduce future disease risk.
Clinical obesity, however, indicates excess adiposity that is actively causing illness signs or symptoms. This condition constitutes a disease itself, regardless of whether other obesity-related conditions are present. Clinical obesity necessitates immediate treatment interventions, including behavioral approaches, medications, and/or surgical options.
How does the redefinition of obesity as a disease with clinical and preclinical stages impact healthcare policy, particularly in terms of resource allocation, treatment accessibility, and prevention strategies? How might this new definition help address the stigma associated with obesity on a systemic level?
Dr. Cummings: Our commission believes these definitional changes will enable more strategic allocation of limited healthcare resources to those with clinical obesity who stand to benefit most from interventions. Additionally, we hope that recognizing clinical obesity as a medical disease rather than simply a willpower failure will contribute to reducing weight stigma.
