New definition of obesity that emphasizes health assessment ignores BMI

among them Growing buzz about Ozempic and similar weight loss drugsa group of 58 researchers is taking on that path. obesity definition and diagnosis, arguing that current methods fail to capture the complexity of the symptoms. They offer a more nuanced approach.

group's Revised definitionwas published in Lancet Diabetes and Endocrinology The Jan. 14 show focuses on how excess body fat, a measure known as adiposity, affects the body. Depends only on body mass index (BMI)relates a person's weight and height. They propose two categories: preclinical obesity, where there is excess body fat but organs function normally, and clinical obesity, where excess fat harms the body's organs and tissues.

This change has the potential to improve clinical care. public health policy Elisabeth van Rossum, an endocrinologist at the Erasmus University Medical Center Rotterdam in the Netherlands, says society's attitudes towards obesity play a role.

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“The idea now is that if you eat less and exercise more, you'll lose weight,” says Van Rossum, who was not involved in the study. A healthy lifestyle is important, but “if it were that simple, we wouldn't have epidemics. This paper is a great contribution to the debate about the complexity of obesity,” she added. .

global issues

More than 1 billion people worldwide are obese, and obesity is associated with approximately 5 million deaths each year. diabetes and cardiovascular disease.

BMI has long been used as a tool to diagnose obesity because it is easy to measure and compare. However, it does not provide a complete picture of a person's health because it does not take into account differences in body composition, such as muscle and fat.

For people of European descent, obesity is usually defined by a BMI of 30 or higher, which correlates with higher levels of body fat. However, while muscular athletes can be classified as obese based on their BMI, those with a “normal” BMI have excess fat, which increases their risk of heart disease and other serious health problems. Possibly, says Francesco Rubino, a bariatric surgeon at King's College. London led a group that proposed a new approach.

Traditional methods end up requiring unnecessary treatment for some people while missing out on people who need help, he says. To address this, Rubino et al. propose a system to diagnose obesity beyond BMI. The system is combined with other methods such as measuring waist circumference, which is a proxy for obesity, and body scans using low-level X-rays. Directly measure fat mass.

There is no fixed threshold for obesity, but body fat above 25% for men and 30-38% for women is usually considered excessive. Measuring obesity directly can be impractical or expensive, so alternative health markers such as waist size, waist-to-hip ratio, or waist-to-height ratio are important, researchers say. say. However, they add that it's safe to assume that people with a BMI over 40 have high body fat.

Study co-author Robert Eckel, an endocrinologist at the University of Colorado Anschutz Medical Campus, said that diagnosing obesity depends on standard laboratory tests, medical history, and how excess body fat affects a person's health. It is also necessary to consider information about activities of daily living to assess the At Aurora. “These are objective diagnostic criteria and are standardized across health systems worldwide,” he says.

Study co-author Louise Bauer, a pediatrician at the University of Sydney in Australia, said certain groups may face health risks even at lower BMI thresholds than others, so consider age, gender and ethnicity. The authors state that individual evaluations conducted by the government are equally important.

two categories

Although people with preclinical obesity have tissues that function normally, they are at higher risk of developing health problems than people without obesity. The group says preventive measures such as counseling and lifestyle changes can reduce the risk of developing more serious health problems.

Clinical obesity occurs when excess fat damages organs or severely limits daily activities such as walking and dressing. People who are clinically obese may require treatment to improve their health and prevent complications.

Rubino said this approach is especially important as the use of weight loss drugs increases because it provides more accurate diagnosis and helps make treatment more effective and cost-effective.

stigma challenge

This approach is supported by dozens of scientific and patient advocacy groups around the world and reflects growing evidence of the health effects of obesity, Van Rossum said. A separate framework released last year also recognized that diagnosing obesity needs to go beyond BMI to include an assessment of health impact.

However, many health care providers still view obesity as a matter of will rather than a disease caused by excess fat, regardless of its underlying causes (which can include hormonal changes and genetic factors). Mr. Van Rossum said. In the Netherlands, for example, a study she co-authored found that most obese patients experience stigma in medical settings. This stigma often prevents people from receiving care, highlighting the need for better education and communication about this condition.

The latest approach aims to better understand obesity, but it's unclear whether it will lead to more or fewer diagnoses, or what impact it will have on the management of the condition in the clinic. . “Over time, we hope that this type of assessment will be incorporated into clinical practice guidelines,” Baur says.

This article is reprinted with permission. first published January 14, 2025.