SoapboxHealth & MedicineObesity needs a new definition beyond BMI, health experts argueBMI labels some people as having a disease, even if their excess body fat isnt causing harm Obesity could get a new definition and diagnostic criteria thanks to a global commission of health experts.Yaroslav Astakhov/iStock/Getty Images PlusBy McKenzie Prillaman2 hours agoObesity needs a new definition, argues a global group of health experts.For over 75 years, obesity has been called a disease by the World Health Organization. But the label is hotly debated. Some say it helps legitimize obesitys seriousness; others point out that people living with obesity are not always ill.So a commission of nearly 60 health experts has proposed a definition and diagnostic criteria for clinical obesity: a disease where excess body fat harms a persons tissues, organs or ability to do daily tasks. The report, published January 14 in the Lancet Diabetes and Endocrinology, also describes preclinical obesity, when surplus body fat does not affect tissues or organs, but may increase the risk for developing clinical obesity, type 2 diabetes, certain cancers and other diseases.