Why South Asians Get Diabetes at a Lower Weight: The Thin-Fat Body

A slim man with a sugar problem

A 38 year old man in Lahore walks into a clinic. He is not fat by any normal measure. His shirt fits fine, his BMI is 24, and he has never been told he is overweight. A routine blood test comes back with a fasting glucose that says type 2 diabetes. He is genuinely surprised. So are many of his relatives, who carry the same build and the same diagnosis. His case is a textbook picture of diabetes in South Asians.

This scene repeats across Pakistan, India, Bangladesh, and Sri Lanka every single day. It is the central puzzle the region keeps running into: people get the disease while looking lean, at weights that would barely register as a risk in a clinic in London or Toronto. The explanation is not bad luck or weak willpower. It is the way South Asian bodies are built and the way refined carbohydrate has flooded the modern Pakistani plate.

What “thin-fat” actually means

The term sounds like a contradiction. It is not. The thin-fat body is the single best explanation for diabetes in South Asians, and once you understand it the early diagnoses stop being a mystery. “Thin-fat” describes a body that reads as normal weight on the scale but carries a high percentage of fat and an unusual amount of it in the worst place. Researchers first used the phrase to describe South Asian newborns who were light at birth yet already had relatively high body fat. The pattern follows people into adult life.

More fat at the same weight

Put a South Asian adult and a white European adult of the same height, weight, and BMI side by side, and measure their actual body composition. Studies using detailed body scans find the South Asian person usually carries several percentage points more fat. The muscle that should be there, the metabolically active tissue that soaks up blood sugar, is in shorter supply. A scale cannot see any of this. It reports two identical numbers for two very different bodies.

This is why a young, slim-looking person in Karachi can already be on the road to diabetes while a heavier-looking peer elsewhere is not. The South Asian build front-loads the kind of fat that does metabolic harm and skimps on the muscle that protects against it. Two people can wear the same trouser size and have completely different blood sugar futures. The difference is not visible in a mirror. It shows up only in a body scan or, eventually, in a blood test.

Less muscle to burn sugar

Muscle is where most of the glucose in your blood goes after a meal. It pulls sugar out of the bloodstream and stores or burns it. Less muscle means a smaller sink for that sugar, so glucose lingers higher for longer and the pancreas has to work harder. This is one reason resistance training matters so much for South Asians, a point we come back to. If you want the mechanics of building that tissue, see our piece on how muscles grow.

The South Asian body can look thin on the outside while behaving, on the inside, like a much heavier one.

Why belly fat is the real villain

Not all fat is equal. The soft fat just under your skin, the kind you can pinch, is fairly harmless. The dangerous kind sits deeper, wrapped around the liver, intestines, and pancreas. This is visceral fat, and South Asians tend to store more of it for any given waist size.

Visceral fat and insulin resistance

Visceral fat is not a quiet storage depot. It is metabolically loud. As Harvard Health explains, this deep abdominal fat is far more strongly linked to metabolic disease than the fat under the skin. It releases free fatty acids and inflammatory signals straight into the bloodstream that feeds the liver. Those signals make the body’s cells respond poorly to insulin, the hormone that tells them to take in glucose. That blunted response is insulin resistance, and it is the engine of type 2 diabetes. The pancreas compensates by pumping out more insulin, until one day it cannot keep up. According to the World Health Organization, type 2 diabetes is largely the result of excess body weight and physical inactivity, and the South Asian pattern of fat storage amplifies both effects at lower weights.

Ectopic fat: when the liver and pancreas get greasy

When fat cells fill up, fat starts being stored where it does not belong. Fat inside the liver causes the organ to overproduce glucose and worsens whole-body insulin resistance. Fat inside the pancreas appears to choke the very beta cells that make insulin. This misplaced fat is called ectopic fat, and a slim-looking South Asian can carry a surprising amount of it. It helps explain how someone with a flat-ish stomach and a normal BMI can still have a fatty liver and a struggling pancreas. The same deep-fat problem drives our parallel story on South Asians and heart disease.

Type of fat	Where it sits	How risky
Subcutaneous fat	Just under the skin, pinchable	Low. Mostly cosmetic.
Visceral fat	Deep in the belly, around organs	High. Drives insulin resistance.
Ectopic fat (liver)	Inside liver cells	High. Raises blood glucose, fatty liver.
Ectopic fat (pancreas)	Inside the pancreas	High. Impairs insulin production.

Why your body is built this way

The thin-fat pattern is not a personal failing. It is partly written into early development and partly into genes. Two ideas explain most of the story behind this early-onset pattern, and both start long before adulthood.

The thrifty phenotype and low birth weight

In the 1990s the epidemiologist David Barker proposed that what happens in the womb shapes lifelong disease risk. A fetus that is undernourished, common where mothers are themselves underweight or anemic, adapts by becoming “thrifty”. It prioritises laying down fat over building muscle and organ capacity, on the bet that food will be scarce after birth. South Asia has long had high rates of low birth weight. When that thrifty baby grows up in a world of plentiful refined carbohydrate, the early programming backfires. The body that was tuned for famine meets a flood of sugar.

Catch-up fat and the famine-to-feast switch

The danger sharpens with catch-up growth. A small baby that gains weight rapidly in childhood tends to add fat faster than muscle, deepening the thin-fat build. A single generation in Pakistan has gone from food scarcity to cheap calories, from walking everywhere to riding everywhere. Bodies tuned across centuries for one environment now live in the opposite one. The mismatch shows up as diabetes in the prime of life.

Genes load the gun

Family history matters more for South Asians than for most populations. If a parent or sibling has type 2 diabetes, your own risk climbs steeply. Genetics set the tendency toward central fat storage and lower insulin output. Genes are not destiny here, though. They set the threshold; diet, weight, and activity decide whether you cross it.

Why the BMI chart lies to South Asians

BMI is just weight divided by height squared. It was built mostly on white European populations, and it says nothing about where fat sits or how much muscle you carry. This single tool is part of why so many of these cases go unflagged until they are advanced. For a South Asian, the standard chart is dangerously reassuring. A BMI that looks “healthy” on the global scale can hide a body already deep in metabolic trouble.

The lower cut-offs WHO recommends

After reviewing the evidence, the World Health Organization advised that Asian populations should act on lower BMI thresholds. The point at which health risk starts to climb sits around a BMI of 23, not 25, and the level that warrants real action sits near 27.5, not 30. Waist limits are tighter too, because the waist is a rough read on visceral fat. The numbers below are the practical version of that guidance.

Measure	Standard cut-off	South Asian / Asian cut-off
Overweight (BMI)	25 and above	23 and above
Action / high risk (BMI)	30 and above	27.5 and above
Waist, men	about 102 cm	about 90 cm
Waist, women	about 88 cm	about 80 cm

Why your waist beats your scale

For a South Asian, a measuring tape around the navel tells you more than the bathroom scale. A man whose waist crosses roughly 90 cm, or a woman past roughly 80 cm, is carrying enough central fat to worry about, even at a “normal” weight. If you measure one thing this year, measure your waist. The link between rising belly fat and metabolic risk is the same story we tell in why belly fat arrives at 45.

Diabetes in South Asians, by the numbers in Pakistan

This is not a small problem. The scale of diabetes in South Asians makes it one of the defining health crises of the region.

One of the highest rates on earth

The International Diabetes Federation Diabetes Atlas has repeatedly placed Pakistan among the countries with the highest diabetes prevalence in the world, with roughly a quarter of adults affected and tens of millions living with the disease. India and Bangladesh carry vast absolute numbers too. The South Asian diaspora shows the same pattern wherever it settles, which tells you the cause travels with the body, not the postcode.

Younger, and often undiagnosed

South Asians develop the disease around a decade earlier than white Europeans on average, often in their thirties and forties rather than their fifties and sixties. Worse, a large share do not know they have it. Diabetes can run silent for years while it quietly damages the kidneys, eyes, nerves, and arteries. By the time symptoms force a visit, harm is already done. That silent stretch is exactly why screening matters.

The early-onset pattern carries a heavy cost. A man who develops diabetes at 38 instead of 58 has two extra decades for high blood sugar to erode his blood vessels, which raises his odds of heart disease, kidney failure, vision loss, and amputation later in life. The disease also hits during peak earning years, when a family depends on that income most. In Pakistan, where out-of-pocket spending covers much of healthcare, the financial weight of insulin, strips, and complications lands squarely on households. Prevention is not only kinder to the body. It is far cheaper than treatment.

How to actually lower your risk in Pakistan

The biology is sobering, but the levers are real and local. Lowering your risk of diabetes in South Asians does not require a gym membership or imported food. It requires a handful of changes you can start this week.

Cut the refined carbohydrate load

The modern Pakistani plate leans heavily on fast carbohydrate: white rice, white flour roti, sugary chai, biscuits, mithai, and soft drinks. These spike blood sugar quickly and demand a big insulin response, day after day. You do not have to give up roti and rice. Shift the balance. Swap some white flour for whole wheat or add chana atta, halve the portion of white rice and pad the plate with daal, sabzi, and salad, and take your chai with little or no sugar. The constant sugar drip is also what keeps cravings alive, a loop we unpack in why we crave sugar.

Build muscle, not just lose weight

Because the South Asian problem is partly a muscle deficit, losing weight alone is not enough. Building muscle gives blood sugar somewhere to go. Two or three sessions a week of resistance work, even bodyweight squats, push-ups, and a cheap set of resistance bands at home, raises the body’s capacity to clear glucose. Muscle is also metabolically expensive tissue, which helps the bigger picture covered in the truth about metabolism.

Walk every day

You do not need to run. A brisk 30 to 45 minute walk most days lowers insulin resistance, trims visceral fat, and improves how muscles handle sugar after meals. A short walk after dinner, when blood sugar is highest, is one of the most underrated moves available. It is free, it suits Pakistani neighbourhoods and rooftops, and it works.

Sleep, and watch the stress

Poor sleep and chronic stress both raise blood sugar and push fat toward the belly. Short, broken sleep is linked to worse insulin sensitivity. Aim for seven hours, keep a regular bedtime, and treat sleep as part of your blood-sugar plan, not a luxury. The NHS lists weight, inactivity, and family history as the main type 2 risk factors, all of which sleep and routine quietly influence.

Portion size is the other half of this. A plate of biryani is not banned. The amount is the lever most people overlook. South Asian meals tend to centre the carbohydrate: a mountain of rice, two or three roti, then a small amount of curry on top. Flip that ratio. Make vegetables and protein the bulk of the plate and let rice or roti be the side. Eating the salad and daal first, then the rice, blunts the blood sugar spike that follows. Small, repeatable habits like this beat dramatic diets that never last. The point of managing this risk is consistency across years, not a crash plan for a month.

Screen early, and keep screening

Because the disease strikes young and runs silent here, South Asians should screen earlier than the textbook age. A simple fasting glucose or HbA1c test, easy to get in any Pakistani lab, can catch trouble years before symptoms. If you have a family history, a waist past the South Asian limit, or you had a high-sugar pregnancy, ask for the test even in your thirties.

The honest summary

South Asians are not unlucky and they are not weak. The thin-fat body explains why diabetes in South Asians strikes lean people early, and it also points straight at the fix. They carry a body shape, built by genes and early life, that handles modern refined food badly and shows the damage at weights that look perfectly safe on a chart. The fix is not despair. It is to stop trusting the scale, start trusting the waist, eat fewer fast carbohydrates, build a bit of muscle, walk daily, sleep, and get a cheap blood test early. The disease is common in Pakistan. It is also, to a real degree, preventable.

Frequently asked questions

Why do South Asians get diabetes at a normal weight?

At the same BMI, South Asian bodies carry more total fat, more deep belly fat around the organs, and less muscle than white European bodies. That deep visceral fat drives insulin resistance, and the lower muscle mass means less capacity to clear blood sugar. So diabetes can develop while the scale and the standard BMI chart still read as normal.

What is the “thin-fat” body?

Thin-fat describes a person who looks slim and has a normal weight but carries a high proportion of body fat, much of it deep in the abdomen, with relatively little muscle. The pattern often starts at birth in South Asians, who tend to be light babies with relatively high body fat, and it tracks into adult metabolic risk.

What BMI should South Asians worry about?

Lower numbers than the global chart. WHO guidance treats a BMI of 23 and above as overweight for South Asians and 27.5 and above as the point for active intervention, rather than the usual 25 and 30. Waist limits are tighter too: roughly 90 cm for men and 80 cm for women.

How common is diabetes in Pakistan?

Very common. The International Diabetes Federation Atlas has placed Pakistan among the countries with the highest diabetes prevalence in the world, with roughly a quarter of adults affected and tens of millions living with the disease. South Asians also tend to develop it about a decade earlier than white Europeans.

Can the thin-fat pattern be changed?

You cannot change your genes or birth weight, but you can change what they lead to. Cutting refined carbohydrate, building muscle through resistance exercise, walking daily, sleeping well, and losing visceral fat all lower insulin resistance. Many people reduce their risk substantially, and some in early stages improve their blood sugar markedly through these changes.

What foods raise diabetes risk most for South Asians?

The fast carbohydrates that dominate many local plates: large portions of white rice, white flour roti and naan, sugary chai, soft drinks, fruit juice, mithai, biscuits, and white bread. These spike blood sugar and demand heavy insulin output. Balancing them with daal, vegetables, whole grains, and protein keeps blood sugar steadier.

When should I get tested for diabetes?

Earlier than the usual age if you are South Asian. Consider a fasting glucose or HbA1c test from your thirties if you have a family history, a waist above the South Asian limit, or symptoms like constant thirst, frequent urination, blurred vision, or slow-healing wounds. Early testing catches the disease during its long silent phase.