For decades, Body Mass Index (BMI) has been the parameter used to measure obesity. If your BMI was 25 or less you were considered to have normal weight. But if your BMI strayed above 25 but stayed below 30, you were considered overweight. Should your BMI exceed 30, you crossed into the land of OBESITY. This has long been the standard and BMI charts are easily available to make a determination based on height and weight.
Recently, however, researchers and clinicians have decided there’s “garden-variety” obesity and then there’s OBESITY. The difference lies in the presence of significant co-morbidities. Overweight people have more co-morbidities than normal weight individuals, anyway, but their presence changes the definition and puts heavy individuals in a more serious category of OBESITY.
OBESITY is most often accompanied by co-morbidities such as hypertension, arthritis, diabetes, and cardiovascular disease. The overweight/obese adult who has one or more of these co-morbidities increases his/her risks of cardiovascular disease and death by entering the more severe disease category, OBESITY.
Another parameter used to re-define obesity is the term Central Adiposity. It is generated by measuring the waist circumference, but that is only a “close” measure of the total central fat accumulation. Central adiposity is the presence of fat tissue around the abdominal and chest cavities, and also that which surrounds the abdominal and chest (thoracic) viscera (internal organs). The presence of central adiposity is strongly correlated to cardiometabolic risk. Central fat accumulation definitely increases the risk of diabetes and cardiovascular disease. It becomes a vicious cycle with co-morbidities begetting obesity and obesity begetting co-morbidities, and on…..
Medical science is always trying to increase accuracy and reliability and needs a better way to measure central adiposity. A tape measure around the belly or chest cannot give accurate measures of intra-abdominal or intra-thoracic fat. Techniques such as a soft tissue variant of a DEXA bone scan or new technology, digital anthropometry are needed today. These non-invasive techniques are able to give doctors more pertinent information to determine if the patient is obese or OBESE! Striving for accuracy and reproducible precision is a goal of medical researchers and statisticians. Most of the time, one can tell if a person is obese simply by looking at them. BUT from a research/therapeutic perspective, having a more precise determination is important prognostically.
Dr. G’s Opinion: The new definition of obesity includes the presence of hypertension, diabetes, arthritis, and cardiovascular disease, the so-called co-morbidities, that affect the long term risks of an overweight adult. Adding chronic diseases to an elevated BMI increases a person’s chances of a bad outcome long term. That overweight patient is really OBESE and not just obese. An additional study found that the “new definition” re-classified 18.8% of overweight people into the OBESE category.
Reference: Tucker ME. New Obesity Definition Raises the Number Who have it. Medscape 2025 July 8.
