New Framework for Obesity Diagnosis Shows Limitations of BMI
A new approach to diagnosing obesity, which incorporates measurements of abdominal fat and organ function, has been found to be more accurate than the traditional body mass index (BMI) method. The study highlights the…
A recent study suggests that a more-nuanced approach to diagnosing obesity could significantly improve diagnosis, identify individuals at higher risk of illness, and help clinicians determine who needs treatment. This approach combines measurements of abdominal fat with assessments of organ function to distinguish between people who are harmed by obesity and those who are not. The framework has two steps: first, clinicians use waist circumference and waist-to-height ratio alongside BMI to establish whether someone has excess body fat, and second, they assess whether that excess fat is causing harm by looking at organ dysfunction. This method provides a more accurate picture of obesity-related health risks than BMI alone. [1]
The study analyzed data from 844,108 adults across four countries and found that BMI alone misdiagnosed a significant number of individuals. Between 1.2 and 3.1 percent of people were classified as obese when the new framework suggests they do not have the condition, while between 5.2 and 8.6 percent had excess body fat that was missed by BMI. These findings indicate that BMI is not an ideal measure of health and that it can label some people as having obesity when they do not and miss others who do. The study also found that the risk of mortality was better predicted by excess body fat, not BMI alone. [1]
According to the World Health Organization (WHO), in 2024, 1 in 7 people (1.1 billion) worldwide were living with obesity. The prevalence of overweight and obesity has increased dramatically since 1990, with adult obesity more than doubling and adolescent obesity quadrupling. The WHO defines overweight and obesity based on BMI, but the new framework suggests that a more comprehensive approach is needed to accurately assess and treat obesity. This highlights the need for updated diagnostic criteria that take into account factors beyond BMI to better identify individuals at risk and provide appropriate care. [2]
A recent study suggests that a more-nuanced approach to diagnosing obesity could significantly improve diagnosis, identify individuals at higher risk of illness, and help clinicians determine who needs treatment. The study analyzed data from 844,108 adults across four countries and found that BMI alone misdiagnosed a significant number of individuals. According to the World Health Organization (WHO), in 2024, 1 in 7 people (1.1 billion) worldwide were living with obesity (WHO, 2024). [1] [2]
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Not all obesity should be classified in the same way. Body mass index (BMI), which divides a person’s weight by their height squared, comes with fundamental and well-acknowledged problems for diagnosing obesity. It can’t distinguish fat from muscle, tell us where fat is distributed in the body or determine whether excess body fat is actually affecting someone’s health. Now, a very large international study suggests that a more-nuanced approach could substantially improve obesity diagnosis, identify people at elevated risk of illness and mortality, and help clinicians determine who needs treatment – and how much (New Scientist Health, 2024). [1]
The study tested a framework proposed by a 2025 Lancet Commission. It combines measurements of abdominal fat with assessments of organ function to distinguish between people who are harmed by obesity and those who aren’t. The framework has two steps. First, clinicians used waist circumference and waist-to-height ratio alongside BMI to establish whether someone actually has excess body fat, known as adiposity. The second part of the framework determines whether that excess fat is actually causing harm (New Scientist Health, 2024). [1]
The study also accounted for well-known differences in BMI and waist measurement thresholds for some ethnic groups. For instance, in populations from South and East Asia, thresholds are lower. However, Sonia Anand, an epidemiologist at McMaster University in Ontario, Canada, says she is less certain that the ethnicity-specific thresholds used in the study represent the optimal global definition of obesity. “Further validation in South Asian, Indigenous and other underrepresented populations using incident diabetes, cardiovascular disease and organ-specific outcomes is still needed,” she says (New Scientist Health, 2024). [1]
Not all obesity should be classified in the same way. Body mass index (BMI), which divides a person’s weight by their height squared, comes with fundamental and well-acknowledged problems for diagnosing obesity. It can’t distinguish fat from muscle, tell us where fat is distributed in the body or determine whether excess body fat is actually affecting someone’s health (Source 1). [1]
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The study tested a framework proposed by a 2025 Lancet Commission. It combines measurements of abdominal fat with assessments of organ function to distinguish between people who are harmed by obesity and those who aren’t. The framework has two steps. First, clinicians used waist circumference and waist-to-height ratio alongside BMI to establish whether someone actually has excess body fat, known as adiposity (Source 1). [1]
In 2024, 1 in 7 people (1.1 billion) worldwide were living with obesity. Worldwide adult obesity has more than doubled since 1990, and adolescent obesity has quadrupled. The diagnosis of overweight or obesity is made by measuring a person’s weight and height and by calculating their BMI (Source 2). [2]
Sources
Prepared with AI assistance from the cited sources.
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