BMI for South Asian Adults

Why the Standard Thresholds Put You at Risk

Last updated: 6 June 2026

If you are of South or East Asian descent and your BMI calculator returns a number in the “healthy” range, the standard interpretation may be wrong for your biology. Not slightly wrong. Significantly wrong, in a direction that directly affects your risk of developing type 2 diabetes and heart disease.

This is not a fringe position. The World Health Organisation, the International Diabetes Federation, the American Diabetes Association, and health authorities across South and East Asia have all formally adopted lower BMI thresholds for these populations. The clinical evidence behind the adjustment has been accumulating for over two decades and is now well-established. The problem is that most general BMI calculators still use the European-derived thresholds without flagging the adjustment — leaving millions of people with an incomplete picture of their metabolic health.

This article explains why the adjustment exists, what the correct thresholds are, and how to use them practically.

Why Body Composition Differs at the Same BMI

The scientific explanation for the South and East Asian BMI adjustment is specific and measurable. It is not about height, frame size, or cultural differences in diet. It is about body composition: the proportion of body weight made up of fat versus muscle and bone at any given BMI.

Multiple population comparison studies — comparing South Asian, East Asian, and European adults at equivalent BMI values — have consistently found that South Asian adults carry a higher proportion of body fat at the same BMI. At a BMI of 23, a South Asian adult will typically have a higher body fat percentage than a European adult of the same BMI.

The mechanism is somewhat more nuanced than is often presented. Research initially focused on visceral (intra-abdominal) fat as the primary driver, but a 2022 systematic review and meta-analysis published in Diabetologia — drawing on imaging data from over 4,000 South Asian and European participants — found that liver fat is the most consistently elevated ectopic fat depot in South Asian adults at equivalent BMI, with visceral fat differences being less clear-cut than previously assumed. [1] A 2007 study using MRI and underwater weighing found that South Asian men had around 6% higher total body fat than Caucasian men for the same BMI, but this excess was primarily truncal subcutaneous fat rather than intra-abdominal visceral fat — and that adipocyte size (which drives insulin resistance independently) was substantially larger in South Asian men. [2]

A landmark 2024 experimental study published in Nature Metabolism — the GlasVEGAS trial — added further precision: when South Asian and White European men without obesity underwent controlled overfeeding to induce 5–7% weight gain, South Asian men experienced a 38% decrease in insulin sensitivity, compared to 7% in White European men, despite similar gains in total body fat. South Asian men also gained less lean tissue during overfeeding. [3] The finding directly demonstrates that weight gain is metabolically more dangerous in South Asian adults — not simply that they carry more fat at baseline.

The practical consequence of all of this is the same: the cardiometabolic risk associated with a given BMI is substantially higher in South Asian adults than European-derived thresholds assume. But it is worth being clear that the mechanism is more complex than “more visceral fat at the same BMI” — it involves differences in adipocyte function, liver fat, lean mass, and intrinsic insulin sensitivity.

The WHO Thresholds — And What They Actually Say

The article’s central claim — that the WHO formally adopted lower BMI thresholds for Asian populations — requires some precision. Following a formal expert consultation published in The Lancet in 2004, the WHO reviewed the evidence and concluded that the proportion of Asian people with high risk of type 2 diabetes and cardiovascular disease is substantial at BMIs lower than the standard overweight cut-off of 25 kg/m². [4]

However, the 2004 consultation stopped short of formally replacing the international BMI cut-off points. Instead, it retained the standard WHO classifications as international benchmarks and identified additional “action points” — 23.0, 27.5, 32.5, and 37.5 kg/m² — as population-specific trigger points that individual countries could use based on their own data. The consultation explicitly acknowledged that the observed risk cut-off “varies from 22 kg/m² to 25 kg/m² in different Asian populations.”

This distinction matters: the BMI thresholds of 23 (overweight) and 27.5 (obese) are widely used clinical action points, supported by strong evidence and adopted in national guidelines across Asia and by NICE in the UK — but they are not a blanket global WHO replacement of the standard thresholds. Presenting them as a definitive replacement risks overstating the degree of consensus.

Asian-Adjusted BMI Action Points

Classification	Standard BMI (European-derived)	Asian-adjusted action point
Underweight	Below 18.5	Below 18.5 (unchanged)
Healthy weight	18.5 – 24.9	18.5 – 22.9
Overweight / Increased risk	25.0 – 29.9	23.0 – 27.4
Obese / High risk	30.0 and above	27.5 and above

These thresholds are used by health authorities in India, Japan, China, Singapore, South Korea, and — via NICE guideline PH46 — the UK. [5] They apply to adults of South Asian descent (India, Pakistan, Bangladesh, Sri Lanka, Nepal) and East Asian descent (China, Japan, Korea, and broader Southeast Asia).

The International Diabetes Federation specifies separate waist circumference thresholds for metabolic syndrome diagnosis in these populations: 90 cm (35.4 inches) for Asian men and 80 cm (31.5 inches) for Asian women, compared to the standard 102 cm and 88 cm respectively.

Practical Translation

If you are of South or East Asian descent:

• A BMI of 23 places you in the overweight/increased risk action point — not “healthy weight”
• A BMI of 27.5 places you in the obese/high risk category — not “overweight”
• Metabolic risk screening (HbA1c, fasting glucose, lipid panel, blood pressure) is clinically warranted at BMI 23, not BMI 25

This recalibration can feel jarring if you have always been told your BMI of 24 is healthy. The point is not to alarm you — it is to ensure you have the correct risk picture so that preventive action happens at the right time.

The Disease Risk: What the Evidence Shows

The adjusted thresholds reflect real, measured differences in disease incidence at lower BMI levels.

Type 2 diabetes. South Asian adults develop type 2 diabetes at markedly lower BMI levels than European populations — with a risk cut-off suggested at 23 kg/m², compared to 25 kg/m² for White European populations. [5] This pattern holds across South Asian diaspora populations in North America, Australia, and Europe. The reason involves higher liver fat at equivalent BMI, larger and more insulin-resistant adipocytes, and intrinsic differences in insulin sensitivity. [1, 2, 3]

In the UK, NICE guideline PH46 specifically recommends that South Asian, Chinese, and Black African or Caribbean adults should be offered diabetes screening at a BMI of 23 kg/m² — a direct clinical implementation of the adjusted threshold. [5] If you are South Asian and have not been screened for pre-diabetes despite a BMI above 23, this represents a gap worth raising at your next GP appointment.

Cardiovascular disease. South and East Asian adults show higher rates of coronary artery disease at equivalent BMI levels compared to European populations, though the relationship is somewhat distinct from the standard BMI-CVD link in European populations. Importantly, INTERHEART and subsequent analyses found that in South Asians, waist-to-hip ratio (a measure of central adiposity distribution) is a stronger predictor of myocardial infarction risk than BMI alone, with higher population-attributable risk from abdominal obesity in South Asians compared to other groups. [6] This makes waist circumference particularly important in this population — see below.

Japan has used a BMI obesity threshold of 25 kg/m² (rather than 30) in national clinical practice since 2000, reflecting its population’s elevated metabolic risk at lower BMI.

The Second Risk: Underdiagnosis at the Standard Thresholds

The practical consequence of applying European-derived BMI thresholds to South Asian adults is systematic underdiagnosis of metabolic risk.

A person of South Asian descent with a BMI of 24 will typically be told by a standard BMI calculator that they are in the healthy weight range. A clinician applying the NICE-recommended adjusted thresholds correctly recognises that this person is in the overweight/increased risk category and that diabetes and cardiovascular screening is clinically warranted.

The same individual, presenting to a GP with no specific complaints and a “healthy” BMI on a standard calculator, may not receive metabolic screening — HbA1c, fasting glucose, lipid panel — until symptoms appear or BMI rises above 30. By that point, insulin resistance may have been present for years, and reversing it is substantially harder than preventing its progression at the BMI 23 to 27.5 stage.

South Asian populations in the UK represent approximately 7% of the population but account for a disproportionate burden of diabetes-related complications and cardiovascular events — a disparity that is, in part, a consequence of using measurement tools calibrated for a different population.

Applying the Adjustment in Practice

If you are of South or East Asian descent, here is how to apply the adjusted thresholds.

Step 1: Calculate your BMI and note the raw number — but do not use the standard category labels to interpret it.

Step 2: Interpret against the adjusted thresholds. If your BMI is 23 or above, you are in the increased risk action point by Asian-adjusted standards. If it is 27.5 or above, you are in the high-risk (obese equivalent) category.

Step 3: Check your waist circumference. Apply the IDF Asian thresholds: above 90 cm (35.4 inches) for men and above 80 cm (31.5 inches) for women indicates high metabolic risk. Measure at the midpoint between the bottom rib and the top of the hip bone, not at the navel. Some guidelines use an even more conservative threshold of 80 cm for women — check with your GP which they apply.

Step 4: Request metabolic screening at your next GP appointment. Specifically: HbA1c, fasting glucose, fasting lipid panel (total cholesterol, LDL, HDL, triglycerides), and blood pressure. If your BMI (Asian-adjusted) is in the overweight or obese range, these tests are clinically warranted regardless of whether you have symptoms. Pre-diabetes, dyslipidemia, and hypertension are all typically symptom-free in their early stages.

The Waist Circumference Check Is Especially Important in This Population

For South and East Asian adults, waist circumference alongside BMI is particularly important. The INTERHEART study found that waist-to-hip ratio was a stronger predictor of myocardial infarction in South Asian populations than BMI. [6] A systematic review and meta-analysis published in BMC Cardiovascular Disorders (2024) confirmed that both BMI and waist circumference are strongly positively associated with CVD risk in South Asians, with similar effect sizes — reinforcing the case for using both measures together. [7]

The IDF waist thresholds for Asian adults (90 cm men, 80 cm women) identify a subset of people at elevated metabolic risk who appear “normal” or only mildly elevated by standard waist cut-offs (102 cm men, 88 cm women). This is not a theoretical concern — it represents a practical, measurable screening gap.

What to Do With an Elevated Risk Reading

If your Asian-adjusted BMI or waist circumference places you in the elevated risk category, the first step is information gathering, not alarm.

Request the blood tests described above. Results above the normal range for HbA1c, fasting glucose, or lipid markers give you actionable targets. Results within normal range, combined with a borderline BMI, indicate that monitoring and prevention are appropriate — not that disease is inevitable.

The lifestyle interventions that reduce metabolic risk in South Asian adults are broadly consistent with general guidance: a modest caloric deficit if excess weight is present, resistance training to preserve and build lean mass, aerobic exercise (with HIIT showing particularly strong evidence for visceral and liver fat reduction), sleep optimisation, and dietary quality improvements. Some evidence suggests that reducing refined carbohydrates may be particularly beneficial given the higher prevalence of insulin resistance in this population, though this remains an area of ongoing research.

The critical clinical difference is that the intervention conversation — and metabolic screening — should happen earlier in this population: at BMI 23 rather than 25, and at waist 80–90 cm rather than standard thresholds. The metabolic risk at equivalent BMI levels accumulates faster than European-derived thresholds assume.

The Bottom Line

The standard BMI calculator is not calibrated for South or East Asian biology. A “healthy” result on a European-derived scale may mask genuine metabolic risk. The WHO, IDF, and national health authorities across Asia — as well as NICE in the UK — have formally acknowledged this with adjusted action points that shift the overweight threshold to 23 kg/m² and the high-risk threshold to 27.5 kg/m².

The mechanism is not simply “more visceral fat” — it involves liver fat accumulation, adipocyte dysfunction, and intrinsically greater insulin sensitivity loss per unit of weight gain. This makes the case for earlier screening compelling across the full range of evidence.

Know your number. Know the correct threshold for your population. Use your waist measurement alongside BMI. And if your BMI is 23 or above and you have not had metabolic screening, raise it at your next appointment — because in this population, earlier detection translates directly into earlier, more effective prevention.

References

1. Caleyachetty R et al. “Liver, visceral and subcutaneous fat in men and women of South Asian and white European descent: a systematic review and meta-analysis.” Diabetologia, 2022. doi:10.1007/s00125-022-05803-5
2. Chandalia M et al. “Insulin Resistance and Body Fat Distribution in South Asian Men Compared to Caucasian Men.” PLOS ONE, 2007. doi:10.1371/journal.pone.0000812
3. Sattar N et al. “Weight gain leads to greater adverse metabolic responses in South Asian compared with white European men: the GlasVEGAS study.” Nature Metabolism, 2024. doi:10.1038/s42255-024-01101-z
4. WHO Expert Consultation. “Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies.” The Lancet, 2004; 363(9403):157–163. doi:10.1016/S0140-6736(03)15268-3
5. NICE Public Health Guideline PH46. “BMI: preventing ill health and premature death in black, Asian and other minority ethnic groups.” Including ethnic-specific thresholds for diabetes screening. Referenced via Bolt Pharmacy clinical guide; see also DiabetesontheNet: diabetesonthenet.com
6. Yusuf S et al. “INTERHEART: Effect of Potentially Modifiable Risk Factors Associated with Myocardial Infarction in 52 Countries.” The Lancet, 2004. Cited via AHA Scientific Statement on South Asian CVD: ahajournals.org
7. Minhas AMK et al. “Associations of general and central adiposity with hypertension and cardiovascular disease among South Asian populations: a systematic review and meta-analysis.” BMC Cardiovascular Disorders, 2024. pmc.ncbi.nlm.nih.gov/articles/PMC10749025

Check your BMI using our BMI Calculator → — then apply the Asian-adjusted thresholds (overweight at 23, obese at 27.5) if you are of South or East Asian descent.