BMI cut-offs for Asian and South Asian adults: 23 and 27.5, and where they come from

Where 23 and 27.5 come from

The two numbers began as action points set by a WHO expert consultation in 2004, not as a new definition of overweight. The consultation met in Singapore in 2002 and published in The Lancet in 2004 (volume 363, pages 157 to 163). It found that Asian populations show a different relationship between BMI, body fat and health risk than European ones, and that the BMI at which risk is first observed varies from 22 to 25 across Asian populations, and at which risk is high from 26 to 31.

Having found no single point, it did not redefine the categories for every population. It agreed that the WHO cut-offs of 18.5, 25 and 30 should be kept as the international classification, and identified further potential public health action points at 23.0, 27.5, 32.5 and 37.5, with a method for countries to decide their own definitions of increased risk.

This is the correction to the most common summary. The line "the WHO says Asians are overweight at 23" is not what the paper says. It says 23 is a point on the BMI scale where a public health response may begin, and that each country should decide.

What NICE says now, and why PH46 is the wrong source

England's guidance turned those action points into the thresholds clinicians use. NICE's obesity guideline NG246 (published 14 January 2025, last updated 8 January 2026) says in recommendation 1.9.11 that people with a South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean background are prone to central adiposity and their cardiometabolic risk occurs at lower BMI, so lower thresholds should be used as a practical measure of overweight and obesity: overweight at 23 to 27.4 and obesity at 27.5 or above. For classes 2 and 3 it says the standard thresholds are usually reduced by 2.5.

Many pages still name NICE public health guideline PH46 (2013) as the source. NICE's page for it now reads "This guidance has been updated and replaced by NICE guideline CG189", and CG189 was in turn replaced by NG246. Cite NG246.

NICE states the lower row values for overweight and obesity directly. The class 2 and class 3 rows follow from its instruction that those classes are usually found by reducing the standard thresholds by 2.5, and the healthy-weight row follows from overweight starting at 23. NICE also adds that BMI should be read with caution in adults with high muscle mass and in people aged 65 and over.

The four numbers people mix up

The 23 and 27.5 figures appear next to 23.9, 26.9 and 25 in articles, and they measure different things.

What the 2021 study found, and why it complicates one number

A study in The Lancet Diabetes & Endocrinology in 2021 used English primary care and hospital records for 1,472,819 adults without diabetes, followed for a median of 6.5 years, 97,823 of whom developed type 2 diabetes. It asked what BMI in each group carried the same diabetes risk as a BMI of 30 in White adults. The answers were 23.9 for South Asian, 26.9 for Chinese, 26.6 for Arab and 28.1 for Black adults.

Two things follow. The South Asian figure is close to NICE's 23 and 27.5 range, so the study mostly supports lowering the line for that group. But the Chinese, Arab and Black figures are well above 23, so a single lower number for every group is a simplification. The study measured one outcome, type 2 diabetes, in one country, and its authors called for revised ethnicity-specific cut-offs. It did not change NICE's recommendation, which stays as 1.9.11 above.

"Asian" is also too broad a label. India, China, Japan and other countries have each set their own lines, and India's 2009 consensus, published by Misra, Chowbey and Makkar, found the limits of normal BMI narrower and lower in Asian Indians than in white Caucasians and was later revised in 2025 to add waist-based criteria. Check your own country's current guidance rather than a table that merges them.

What your weight looks like at each line

A BMI line is a weight at your height. The weight at which BMI reaches a value is that value multiplied by height in metres squared.

At 170 cm and 80 kg, BMI is 27.7. Under the standard categories that is overweight. Under NICE's lower thresholds for the groups it names, it is in the obesity range, which starts at 27.5. At 170 cm and 68 kg, BMI is 23.5: a healthy weight by the standard categories and overweight by NICE's thresholds for those groups. The BMI calculator shows both readings from your height and weight, and the height converter turns feet and inches into the centimetres it needs.

What the number does not tell you

BMI is height and weight only. It cannot see where fat is carried, which is the reason the lower thresholds exist, and it does not separate muscle from fat. NICE recommends reading it alongside waist-to-height ratio, which the waist-to-height ratio guide explains, and with caution in adults with high muscle mass and in people aged 65 and over.

This page explains where published numbers come from. It is not medical advice, and a BMI category is a screening aid rather than a diagnosis, a point the 2025 Lancet Commission made for every group in its clinical and preclinical obesity definition. If you are deciding about your health, a doctor or nurse can say what your own figures mean.