Obesity may need to be defined less by a person’s metabolic test results and more by whether excess body fat is disrupting the function of organs, tissues or everyday activities, according to a new review from researchers at LSU’s Pennington Biomedical Research Center. The authors argue that this shift could help physicians identify which patients need monitoring, intensive medical treatment, weight-loss medication or metabolic surgery.
The review, published in The Journal of Clinical Endocrinology & Metabolism, reexamines the widely used concept of “metabolically healthy obesity.” This term has generally been applied to people who meet criteria for obesity but do not currently show a selected group of metabolic abnormalities, such as elevated blood glucose, high blood pressure, abnormal blood lipids or evidence of insulin resistance. The researchers say the label has helped reveal that obesity affects people differently, but it may be too unstable and inconsistent to guide long-term care.
“Metabolically healthy obesity helped researchers recognize that obesity does not affect every person in exactly the same way,” said Eric Ravussin, an LSU Boyd Professor at Pennington Biomedical and co-author of the review. “But the classification is difficult to use as a foundation for long-term treatment because the definitions vary and metabolic health can change. A person who is considered metabolically healthy today may not be metabolically healthy tomorrow.”
The problem begins with the lack of a universal definition. Studies have used different numbers and combinations of metabolic risk factors to classify people as metabolically healthy or unhealthy. Some definitions exclude individuals with diabetes or hypertension, while others permit one or more abnormalities. As a result, two people with similar levels of body fat may receive different classifications depending on the criteria used by a particular study or clinic.
The designation can also change over time. Excess adiposity, particularly when fat accumulates around internal organs, can influence insulin signaling, inflammatory pathways, blood pressure regulation and lipid metabolism. Adipose tissue is biologically active: it releases hormones and signaling molecules that can affect the liver, skeletal muscle, pancreas, cardiovascular system and immune system. A person who has not yet developed measurable metabolic complications may therefore remain at risk of developing them later.
The newer framework discussed by Ravussin and Christian Rodriguez, a postdoctoral researcher at Pennington Biomedical, distinguishes between preclinical obesity and clinical obesity. Preclinical obesity refers to confirmed excess adiposity without current evidence that the condition is impairing organ or tissue function. People in this category may benefit from structured lifestyle programs, ongoing evaluation of cardiometabolic health and individualized discussions about preventive medication, depending on their age, risk factors and health trajectory.
Clinical obesity, by contrast, is defined as excess adiposity accompanied by obesity-related organ or tissue dysfunction or significant limitations in daily activities. Organ dysfunction can include complications affecting glucose regulation, the cardiovascular system, breathing, mobility or other physiological processes. The framework is intended to identify obesity as a disease state when excess fat is not simply present but is producing measurable harm.
This distinction could change how clinicians decide on treatment intensity. Under the older metabolically healthy/unhealthy model, someone without a defined cluster of metabolic abnormalities might receive lifestyle advice and periodic monitoring, even if obesity was affecting mobility, breathing or another aspect of health. The preclinical/clinical approach would encourage physicians to examine the actual consequences of adiposity rather than relying primarily on a narrow list of laboratory thresholds.
It also changes the way treatment success is measured. Weight reduction remains clinically relevant, but the ultimate goal for a person with clinical obesity would be to improve or resolve the dysfunction caused by excess adiposity. For one patient, that might mean better blood glucose control; for another, improved sleep-related breathing, mobility, blood pressure or cardiovascular function. This outcome-based approach could prevent treatment from being judged solely by the number of kilograms lost.
“Moving from the question ‘Is this person metabolically healthy or unhealthy?’ to ‘Is excess adiposity affecting the function of the body?’ gives us a more clinically meaningful way to think about obesity,” Rodriguez said. “The framework allows us to identify people who may benefit from prevention and monitoring while also recognizing when obesity has progressed to a disease state requiring more intensive treatment.”
The proposed model builds on the work of the Lancet Diabetes & Endocrinology Commission on the Definition and Diagnosis of Clinical Obesity. Ravussin, Pennington Biomedical researcher Philip Schauer and researcher John Kirwan were among the 56 international experts who contributed to the Commission’s work. The Commission’s framework emphasizes that body size alone does not fully describe the health consequences of obesity and that diagnosis should incorporate evidence of impaired function.
The authors stress that the new approach is still developing. Researchers must validate its diagnostic criteria, determine how organ and tissue dysfunction should be measured consistently and create practical tools that can be used in primary care, specialist clinics and public-health systems. There are also questions about how the framework should account for age, disability, ethnic differences, body-fat distribution and conditions that may have multiple causes.
The review concludes that metabolically healthy obesity remains useful for studying the biological diversity of obesity, but its inconsistent definitions, temporary nature and concentration on a limited set of metabolic markers reduce its value as a long-term clinical category. By focusing on whether excess adiposity is causing functional harm, the preclinical/clinical model could offer physicians a more biologically grounded way to match treatment with individual need.
Subject of Research: Obesity definitions, metabolically healthy obesity, clinical obesity, preclinical obesity and obesity-related organ or tissue dysfunction
Article Title: Does metabolically healthy obesity really exist: going toward new definitions
News Publication Date: 24-Jun-2026
Web References: https://academic.oup.com/jcem/advance-article-abstract/doi/10.1210/clinem/dgag247/8715177?redirectedFrom=fulltext; https://doi.org/10.1210/clinem/dgag247; https://www.pbrc.edu
References: Rodriguez C. and Ravussin E., “Does metabolically healthy obesity really exist: going toward new definitions,” The Journal of Clinical Endocrinology & Metabolism, DOI: 10.1210/clinem/dgag247
Image Credits: PBRC; Dr. Christian Rodriguez and LSU Boyd Professor Dr. Eric Ravussin
Keywords: Obesity, metabolically healthy obesity, clinical obesity, preclinical obesity, metabolic health, adiposity, organ dysfunction, diabetes, cardiovascular disease, obesity treatment, pharmacotherapy, bariatric surgery, Pennington Biomedical Research Center
