--- title: Experts Want Obesity Defined Beyond BMI description: Obesity, long determined by the flawed metric of BMI, should be diagnosed based on other measurements and tests, experts argue. canonical: https://time.com/7206816/bmi-diagnose-obesity-new-method/ author: Jamie Ducharme article:opinion: false article:content_tier: free article:published_time: 2025-01-14T23:30:00.000Z article:modified_time: 2026-03-10T23:25:48.993Z article:section: Health og:title: Experts Want Obesity Defined Beyond BMI og:description: Obesity, long determined by the flawed metric of BMI, should be diagnosed based on other measurements, experts argue. og:url: https://time.com/7206816/bmi-diagnose-obesity-new-method/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltccb744b2ea16e174/6998b27d1f67097b0cf541d6/broken-scale.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 og:image:width: 1938 og:image:height: 1090 og:image:alt: Broken scales. og:type: article twitter:card: summary_large_image twitter:title: Experts Want Obesity Defined Beyond BMI twitter:description: Obesity, long determined by the flawed metric of BMI, should be diagnosed based on other measurements, experts argue. twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltccb744b2ea16e174/6998b27d1f67097b0cf541d6/broken-scale.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 ---  # Experts Argue It's Time for Obesity to Be Defined Beyond BMI > Sponsored content. 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Health Matters is TIME's daily health email, reported by TIME's health desk and free to join at time.com/newsletters. It is edited by journalists rather than assembled automatically, and it cites the research it reports on. #### Is Health Matters free? Yes. Health Matters is a free daily newsletter from TIME, available at time.com/newsletters. #### Who reads TIME's Health Matters newsletter? Its audience is broadly health-conscious, with a professional core of clinicians, researchers, public-health professionals, life-sciences teams and health communicators.  by [Jamie Ducharme](https://time.com/author/jamie-ducharme/)  ## Jamie Ducharme Ducharme is a contributor to TIME. Jan 14, 2025 11:30 PM UTC  Tim Robberts—Getty Images  by [Jamie Ducharme](https://time.com/author/jamie-ducharme/)  ## Jamie Ducharme Ducharme is a contributor to TIME. Jan 14, 2025 11:30 PM UTC Body mass index (BMI) is one of the most ubiquitous yet controversial metrics in medicine. A crude measure of weight relative to height, BMI is commonly used to diagnose obesity—even though many experts and [professional groups](https://www.ama-assn.org/press-center/press-releases/ama-adopts-new-policy-clarifying-role-bmi-measure-medicine) agree it’s an imperfect tool that on its own [reveals very little about someone’s health](https://time.com/4755839/bmi-weight-loss-tips/). Among other issues, BMI does not differentiate between weight from fat versus muscle and was [not designed to assess a diverse array of bodies](https://journalofethics.ama-assn.org/article/how-use-bmi-fetishizes-white-embodiment-and-racializes-fat-phobia/2023-07). It’s time to do better than BMI, an international group of 58 experts from fields including obesity medicine, endocrinology, bariatric surgery, cardiovascular medicine, gastroenterology, and primary care argue in a [proposal](https://www.thelancet.com/commissions/clinical-obesity) published Jan. 14 in _The Lancet Diabetes & Endocrinology_. In most cases, the experts write, clinicians diagnosing obesity should either augment or replace BMI readings with other body measurements, such as waist circumference, or tests that can objectively measure body fat. (Tests that precisely measure body fat are already available in some medical clinics, but they are used far less frequently than BMI because they are more costly and labor-intensive.) The proposal also calls for dividing obesity into two categories: clinical and preclinical. Under the group’s definitions, clinical obesity is accompanied by health problems tied to excess body fat, such as impaired organ function, reduced mobility, or difficulty carrying out day-to-day activities. People with preclinical obesity, meanwhile, do not have immediate weight-related health concerns. The former constitutes an illness, while the latter is a health risk to monitor, says Dr. Francesco Rubino, chair of metabolic and bariatric surgery at King's College London and chair of the expert commission. Rubino calls his group’s framework “the most radical change that has been proposed for the diagnosis of obesity.” He says it constitutes “a new diagnosis…that is meant to be objective and pragmatic enough to be globally relevant.” Clinicians are under no obligation to follow the group’s proposal, but 76 medical organizations around the world—including the American Heart Association, the American Diabetes Association, and the World Obesity Federation—have endorsed the report. “This new approach demands a fundamental change in how we treat obesity,” says Dr. Sahar Takkouche, an obesity-medicine specialist and associate chief medical officer at Vanderbilt University Medical Center who was not part of the expert panel. Implementing its recommendations won’t be seamless, Takkouche says. Machines that precisely measure body composition, for example, aren’t available in every doctor’s office, and insurance policies often lag behind evolving medical practices. But the approach outlined in the proposal offers “new hope for more effective care.” The proposed criteria could, for example, help clarify which patients are likely to benefit from treatments like drugs and surgery, Rubino says. While these may be good options for some people with clinical obesity, he says, people with preclinical obesity may not need intensive treatments, like [ultra-popular anti-obesity drugs Wegovy and Zepbound](https://time.com/7199613/which-weight-loss-drug-is-best-wegovy-zepbound/). For some preclinical patients, monitoring alone might be appropriate, he says. "Obesity is nuanced. It’s a spectrum,” Rubino says. “It’s not a single thing.” That distinction alone requires a mindset shift, says Dr. Tirissa Reid, an endocrinologist, obesity-medicine specialist, and associate professor of medicine at Columbia University Irving Medical Center who was not involved in the _Lancet_ proposal. Reid says she and most other obesity specialists already do much of the testing and analysis the report suggests. But, she says, it’s “a big deal” for a group of experts to further the idea that “excess body fat doesn't necessarily equate with illness automatically.” That message could both “reframe” the general public’s understanding of obesity, Reid says, and also help clinicians decide if, when, and how to treat patients. There has [long been debate](https://www.science.org/content/article/obesity-doesn-t-always-mean-ill-health-here-s-what-scientists-are-learning) within the medical community about [whether obesity should be treated as a disease](https://time.com/6330809/ozempic-wegovy-mounjaro-healthy/). The U.S. Centers for Disease Control and Prevention and the American Medical Association both call obesity a disease, but some doctors argue that label is wrong—or at least overly simplistic. While many studies have shown that obesity is associated with chronic health problems including Type 2 diabetes and heart disease, there is less research to concretely prove it _causes_ these conditions, says Dr. Lisa Erlanger, a clinical professor of family medicine at the University of Washington School of Medicine and president of the Association for Weight and Size Inclusive Medicine. Some people with obesity show no signs of chronic conditions, [studies have found](https://pubmed.ncbi.nlm.nih.gov/25040597/), and other research suggests weight stigma and inadequate health care [are associated with many of the same issues frequently attributed to obesity](https://www.health.harvard.edu/blog/weight-stigma-as-harmful-as-obesity-itself-202206022755). Erlanger says the new proposal—which, she notes, was authored by many people with ties to the weight-loss industry—looks like progress on the surface, but is flawed. It still assumes “any impairment occurring while you’re fat” counts as illness and encourages clinicians to use metrics, like waist circumference, that are “poor measures of how many of a person’s symptoms are actually caused by the number of their fat cells,” Erlanger says. In general, she says, the mainstream medical community is “uncurious” about whether obesity actually causes many of the complications it’s linked to, and whether weight loss is truly the best treatment for some of these problems. Habits like getting adequate exercise, nutrition, and sleep can have profoundly positive effects on overall health whether they affect weight or not, Erlanger says. [A recent research review](https://bjsm.bmj.com/content/early/2024/11/07/bjsports-2024-108748), for example, found that cardiorespiratory fitness is a better predictor of longevity than weight. It’s in part because of such debates in the field, Rubino says, that there’s a need for nuanced yet accurate methods of assessing obesity and its health effects—which, he says, his group has produced. “Disease should not be a matter of opinion,” he says. “It should be a matter of fact.” ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/7206816/bmi-diagnose-obesity-new-method/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/7206816/bmi-diagnose-obesity-new-method/"},"headline":"Experts Argue It's Time for Obesity to Be Defined Beyond BMI","datePublished":"2025-01-14T23:30:00.000Z","dateModified":"2026-03-10T23:25:48.993Z","description":"Obesity, long determined by the flawed metric of BMI, should be diagnosed based on other measurements and tests, experts argue.","url":"https://time.com/7206816/bmi-diagnose-obesity-new-method/","keywords":["medicine","healthscienceclimate"],"thumbnailUrl":"https://static.time.com/v3/assets/bltea6093859af6183b/bltccb744b2ea16e174/6998b27d1f67097b0cf541d6/broken-scale.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","author":[{"@type":"Person","name":"Jamie Ducharme","jobTitle":"Ducharme is a contributor to TIME.","url":"https://time.com/author/jamie-ducharme/"}],"articleSection":"Health","image":[{"@type":"ImageObject","url":"https://static.time.com/v3/assets/bltea6093859af6183b/bltccb744b2ea16e174/6998b27d1f67097b0cf541d6/broken-scale.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","width":1200,"height":675,"headline":"Broken scales.","caption":"A photo illustration of a broken bathroom scale.","creditText":"Tim Robberts—Getty Images","representativeOfPage":true}],"publisher":{"@type":"Organization","name":"Time","url":"https://time.com/","logo":{"@type":"ImageObject","url":"https://time.com/images/logo.png","width":528,"height":156},"foundingDate":"March 3, 1923","sameAs":["https://www.facebook.com/time","https://www.instagram.com/time/?hl=en","https://twitter.com/time","https://www.pinterest.com/timemagazine"]}},{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/section/health/","name":"Health"}},{"@type":"ListItem","position":2,"item":{"@id":"/tag/medicine/","name":"medicine"}},{"@type":"ListItem","position":3,"item":{"@id":"https://time.com/7206816/bmi-diagnose-obesity-new-method/","name":"Experts Argue It's Time for Obesity to Be Defined Beyond BMI"}}]}] ```