Why BMI is different for Indians

The short answer

At any given BMI, South Asian adults tend to carry a higher percentage of body fat — and more of it around the abdomen and organs — than white European adults of the same height, weight, age and sex. The consequence is that the health risks normally associated with a BMI of 25 or 30 start appearing at lower numbers. In 2002 a WHO expert consultation met in Singapore to look at exactly this, and published its conclusions in The Lancet in January 2004.

Two things came out of it, and most websites only report one of them:

• The consultation identified additional public-health action points along the BMI scale for Asian populations — at 23.0, 27.5, 32.5 and 37.5 kg/m².
• It also deliberately kept the existing international classification (overweight ≥25, obese ≥30) so that data from different countries stays comparable.

So the honest framing is not "Asians have different BMI categories." It is: the international categories still exist, and alongside them there is a second set of trigger points at which an Asian population should already be acting. This site shows you both, side by side, on every page — because seeing "normal" on one scale and "overweight" on the other is far more informative than seeing either alone.

What "more fat at the same BMI" looks like

BMI does not measure fat. It measures the relationship between your weight and your height, and then assumes a typical body composition. The assumption is where the trouble starts. Studies comparing body-fat percentage across ethnic groups have repeatedly found that South Asian adults sit several percentage points higher in body fat at an identical BMI — often described as the "thin-fat" phenotype: normal weight on the scale, high fat and low muscle underneath, with a disproportionate share of that fat sitting deep in the abdomen around the liver and pancreas.

Visceral fat is the kind that matters most metabolically. It is the reason a person who looks slim can still develop insulin resistance, and the reason India has one of the largest diabetic populations in the world at average body weights that would be unremarkable in Europe.

What the numbers mean in practice

Take a woman who is 5'3" (160 cm) and weighs 60 kg. Her BMI is 23.4. On the standard WHO scale she is comfortably normal. On the Asian-Indian scale she has just crossed the first action point. Nothing about her body changed between those two sentences — only the reference population did.

That does not mean she is unwell, and this is where a lot of health writing goes wrong. An action point is not a diagnosis. It is a signal to look at the other things that actually predict risk: waist circumference, family history of diabetes, blood pressure, activity level, and how the number has moved over the last few years. Crossing 23 is worth noticing. It is not worth panicking about.

The stricter Indian view

There is a third set of numbers you will encounter. In 2009, a consensus group of Indian physicians (Misra and colleagues) proposed that for Indians living in India, overweight should begin at BMI 23 and obesity at BMI 25 — stricter than the 27.5 used here — along with waist action points of 90 cm for men and 80 cm for women.

This site uses 27.5 for the obese band because it comes from the WHO consultation and is the figure most widely used in international comparisons of Asian populations. If your BMI sits between 25 and 27.5, you should know that a substantial body of Indian clinical opinion would already classify that as obesity. Both views are published, both are defensible, and pretending there is a single agreed line would be dishonest. The method page sets this out in full.

What BMI still cannot tell you

None of this rescues BMI from its basic limitations. It cannot distinguish muscle from fat, so a well-trained person can read as overweight on any scale. It behaves oddly at the extremes of height. It says nothing about where fat sits, which is arguably the most important question of all for Indian bodies — which is why a tape measure around your waist is a better five-second test than any BMI calculator, including this one.

Use BMI as a rough population-level screen and as a way to notice direction of travel over years. Use waist circumference for the risk question. Use neither as a verdict on your health.