Why belly fat shows up earlier in South Asian women — at a weight that looks fine

Almost every BMI chart you have ever seen uses the same numbers: under 18.5 is underweight, 18.5 to 24.9 is normal, 25 and over is overweight, 30 and over is obese.

Those cutoffs came from studies of mostly white European populations. In 2004 the World Health Organization published something that never quite made it into everyday conversation in Pakistan or India: for Asian populations, the thresholds sit lower.

• Healthy: 18.5 to 22.9
• Overweight: 23 and above
• Obese: 27.5 and above

Which means a woman whose BMI is 24 — comfortably "normal" on the chart taped to the wall — is already in the overweight band on the one that describes her body.

This is not bureaucratic fiddling. It came from an observation that kept repeating across large studies: type 2 diabetes and metabolic syndrome start appearing in Asian populations at a BMI of around 22 to 23, where in European populations the same conditions tend to show up as BMI approaches 25 and beyond.

Same disease. Several BMI points earlier.

The mechanism behind it is the part worth understanding. At the same BMI, people of South Asian heritage carry roughly 3 to 5% more body fat than white Europeans — and, crucially, more of it is stored centrally, around the abdomen.

There is a second half to that, and it is the half that explains the belly. South Asian bodies appear to have a more limited capacity to store fat subcutaneously, in that layer under the skin. When that layer fills up, the fat does not simply stop arriving. It gets deposited in places it does not belong — around the organs, and inside the liver and pancreas. Researchers call this ectopic fat.

So the pattern is not that South Asians "get fatter". It is that the same amount of fat ends up somewhere more metabolically expensive.

There is a phrase in the research literature for this: thin outside, fat inside.

It describes someone whose weight and BMI look entirely unremarkable, who has never been called overweight by anyone, and whose visceral fat and insulin resistance tell a different story. If you have ever known a slim relative who developed diabetes and everyone said but she was never even heavy — this is usually what was going on.

It is also why "you don't need to lose weight" can be true and unhelpful at the same time. Weight was never the thing being measured.

For South Asian bodies, waist circumference is a more honest signal than weight, and it costs nothing to check.

The thresholds used for Asian populations:

• Women: under 80 cm (about 31.5 inches)
• Men: under 90 cm (about 35.4 inches)

How to do it properly: stand up, breathe out normally, and measure around your abdomen at the level of your belly button. Do not suck in. Do not pull the tape tight enough to dent your skin. Do it in the morning, before eating, so you are comparing like with like next time.

One number, once a month, in the same conditions. That is the whole protocol.

And to be clear about what it is: a screening signal, not a diagnosis. Being over the line does not mean you have anything. It means it is a reasonable thing to mention to a doctor.

Almost nothing about what you cook, and quite a lot about how much and what with. This is the part where most advice goes wrong for desi households, because it starts by telling you to stop eating the food your family eats.

Practical, and compatible with a normal kitchen:

• The roti is not the problem; the ratio is. A plate that is mostly roti and rice with a spoon of salan is a different meal from one where daal, sabzi and protein take up most of the space and the roti fills the rest.
• Add protein to breakfast. Paratha and chai alone is a carbohydrate meal with a long gap after it. An egg, or dahi, or leftover daal changes the whole morning.
• Eat the salad first. Kachumber before the main plate is one of the few habits that costs nothing, changes nothing about the cooking, and reliably reduces how much of everything else you want.
• Chai counts. Four cups a day with two sugars each is not a small number, and it is invisible because nobody thinks of it as eating.
• Walk after dinner. Twenty minutes. It is the single most underrated thing on this list and the easiest to fit into a household routine.

Not to give you a new thing to worry about. There is enough of that.

The point is that a lot of South Asian women have been told for years that their numbers are fine while something was quietly not fine, and have then been blamed for it later. Knowing the thresholds that actually apply to your body means you get to act early, on real information, instead of finding out at 45.

And it means that when a plan does not work, you have a better question than what is wrong with me — you have was that plan ever built for a body like mine.