Body Mass Index was developed in the 1830s using Western European population data. The cutoffs, underweight below 18.5, normal 18.5-24.9, overweight 25-29.9, obese 30+, were calibrated on that same population. For people of South Asian descent, including Pakistanis and Indians, these cutoffs significantly underestimate cardiovascular and metabolic risk.
The Research Evidence
Multiple large-scale studies have found that South Asians develop type 2 diabetes, cardiovascular disease, and metabolic syndrome at lower BMI values than Western populations. A WHO expert consultation in 2004 reviewed evidence across Asian populations and concluded that health risks are significant at BMI 23+ for Asians, compared to 25+ for Westerners.
The Asia-Pacific action thresholds: overweight at 23, obese at 27.5, compared to the global 25 and 30.
Why the Difference Exists
At the same BMI, South Asians tend to have higher body fat percentage and more visceral fat, stored around internal organs in the abdominal cavity. Visceral fat releases inflammatory cytokines and drives insulin resistance in ways that subcutaneous fat (under the skin) does not. South Asians also tend to have smaller bone frames and less muscle mass relative to European populations, making weight-for-height comparisons misleading.
The Diabetes Connection Is Especially Important for Pakistan
Pakistan has one of the highest rates of type 2 diabetes in the world, affecting an estimated 26-33% of adults. Research published in the Pakistan Journal of Medical Sciences and by Aga Khan University consistently shows that Pakistani adults are diagnosed with diabetes at lower BMI values than Western counterparts, often between 22 and 25. A person with BMI 24 who would be classified as normal by global standards may already be at significant metabolic risk.
Better Metrics to Use Alongside BMI
Waist circumference is arguably more useful than BMI for South Asians. WHO recommends South Asian men aim for under 90 cm and women under 80 cm. To measure correctly: stand upright, exhale normally, and measure around the abdomen at the midpoint between the lowest rib and the top of the hip bone. Do not pull the tape tight; it should sit snugly without compressing skin.
Waist-to-height ratio (waist divided by height, both in the same units) should ideally be below 0.5 for adults. This single number has been shown in research to predict cardiovascular risk more accurately than BMI alone across most ethnic groups.
Body fat percentage provides a more direct measure of adiposity. For South Asian men, health risk increases above 20-23% body fat; for women, above 30-33%. CalcsVault's Body Fat Calculator uses the US Navy method, which gives a reasonable estimate without specialist equipment.
Practical Steps
Use BMI as one data point but apply the adjusted Asia-Pacific thresholds: if your BMI is 23 or above, treat it as overweight and review your waist circumference and blood glucose. If your waist exceeds the recommended limits, prioritise this alongside BMI. Annual blood glucose testing after age 35, or earlier with a family history of diabetes, gives direct metabolic information that no weight measurement alone provides.
Conclusion
Use the Asia-Pacific adjusted thresholds (overweight at 23+, obese at 27.5+) rather than the global cutoffs for South Asian adults. Supplement BMI with waist circumference measurement and annual blood glucose and blood pressure testing. CalcsVault's BMI Calculator includes both global and Asia-Pacific classifications so you can see your results under both standards.
For practical BMI calculation steps, a worked example, and action-based health guidance specifically for Pakistani adults, see BMI Calculator Guide for Pakistan.