Health · Medical Research · 1 hr ago
New obesity diagnosis method adds body measurements and organ checks to BMI
Doctors tested a new way to diagnose obesity that uses more than body mass index, or BMI.
BMI compares a person's weight with their height, but it can miss excess body fat or wrongly label someone as obese.
Researchers examined health records for more than 800,000 people in the UK, US, China and Spain, tracking health for up to 15 years.
The method combines BMI with waist measurements and a waist-to-height ratio, then checks whether excess fat is affecting organ function.
It distinguishes clinical obesity, an active disease, from pre-clinical obesity, where excess fat is a health risk but has not yet impaired organs.
The researchers estimated that BMI alone misses obesity in 5% to 9% of adults and wrongly diagnoses it in up to 3%.
The method may help doctors tailor care to each person's health, though it makes diagnosis more complex and could inform choices such as lifestyle advice, weight-loss drugs or surgery.
A study suggests that combining BMI with body measurements and organ-function checks could improve obesity diagnoses.
The approach aims to identify excess body fat and distinguish between clinical obesity, which affects organ function, and preclinical obesity, which does not.
Researchers analysed health data from 844,108 adults in China, the UK, the US and Spain.
The study found that BMI alone missed some people with excess body fat and classified some people as obese when the new framework did not.
Researchers say the approach could help clinicians tailor treatment to patients’ health needs.
- Who
- Researchers led by Francesco Rubino of King’s College London.
- What
- They tested an obesity diagnosis framework combining BMI, body measurements and checks of organ function.
- When
- The study was published on Wednesday, 11 November 2026.
- Where
- The research analysed data from adults in China, the UK, the US and Spain.
- Why
- BMI alone can misclassify people and does not show whether excess body fat is affecting their health.
This story does not have two clearly opposing sides.
A Lancet Commission proposed the diagnostic framework.
The study testing the framework was published in Nature.
- Participants
- 844,108 adults
- Countries
- China, the UK, the US and Spain
- BMI-only missed excess adiposity
- 5.2% to 8.6% of adults
- BMI-only overdiagnosis
- 1.2% to 3.1% of adults
- Clinical obesity
- 23% to 31% of obesity cases
- Preclinical obesity progressing within 10 years
- Around 10% to 30% of people
4 sources
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What people are saying
This misclassification can account for tens of millions of people, so the inaccuracy of BMI is a big problem at scale and also for individuals
BMI misses a lot of information
In countries with large populations, you’re talking about misdiagnosing tens of millions of people – this is not a trivial difference