New Obesity Definition Could Lower Global Rates

Download IPFS

A new multinational study co-authored by researchers from the University of Queensland has raised concerns over a proposed change in how obesity is clinically defined, cautioning that the shift could dramatically lower reported obesity rates but undermine prevention and early intervention.

Published in PLOS Global Public Health, the study involved researchers from universities in Australia, the United States, China, and Peru. It analyzed data from over 142,000 adults across 56 countries to assess how redefining clinical obesity could impact global prevalence estimates.

Currently, obesity is primarily defined using Body Mass Index (BMI), a calculation based on an individual’s height and weight. The proposed change would redefine clinical obesity to apply only to individuals with a high BMI who also have at least one related cardiometabolic condition such as high blood pressure, diabetes, high cholesterol, or a high waist-to-height ratio.

According to the researchers, applying this new definition would cause a sharp drop in reported obesity rates in many countries. In Malawi, for example, obesity prevalence among men would decline by 68 percent and among women by 53 percent. However, the researchers emphasize that this drop does not reflect improved health outcomes but rather a more restrictive diagnostic framework.

Dr Rodrigo M. Carrillo-Larco of Emory University, a co-author of the study, warned that the apparent decline is misleading. “It’s an artificial drop,” he said. “People with high BMI are still at risk and should continue receiving health guidance, even if they don’t meet the new clinical threshold.”

The study authors acknowledged that incorporating metabolic risk factors may offer a clearer picture of disease burden, but they warned it could also complicate health policy and limit access to care. Individuals who are no longer classified as obese under the new standard might delay taking preventive steps or lose eligibility for medical support.

The researchers stressed that while it is important to refine diagnostic criteria to reflect actual health risks, changes should be made carefully to avoid unintended consequences. The study concludes that public health systems must remain vigilant and inclusive, as poor diet and lifestyle continue to drive obesity-related illness globally.

Australians, like populations worldwide, would still face health risks from excess weight even without a formal diagnosis under the revised definition.