BMI for Asians: Healthy BMI Range, Asian-Pacific Cutoffs and Waist Size

Body Mass Index (BMI) is the most widely used quick check of whether your weight suits your height. But the standard international cutoffs were developed mainly from European populations. Research shows that people of South and East Asian origin, including Sri Lankans, tend to have a higher percentage of body fat, and more fat around the abdomen, at the same BMI. As a result they develop type 2 diabetes, high blood pressure and heart disease at lower BMI values. This is why separate cutoffs for Asians are recommended.

How BMI is calculated

BMI = weight in kilograms ÷ (height in metres × height in metres).

For example, a person weighing 68 kg and measuring 1.65 m has a BMI of 68 ÷ (1.65 × 1.65) = about 25.0. You can skip the maths with our BMI calculator, which shows both Asian-Pacific and global WHO categories.

BMI categories for Asian adults

The WHO expert consultation (2004) proposed these public health action points for Asian populations:

• Below 18.5: underweight
• 18.5-22.9: healthy range (low risk)
• 23.0-27.4: increased risk
• 27.5 and above: high risk

Some Asian-Pacific guidelines use a slightly different scheme in which 23-24.9 is called overweight and 25 or higher obese. In either system, the message is the same: risk begins to rise from about BMI 23.

For comparison, the global WHO classification defines 18.5-24.9 as normal, 25-29.9 as overweight and 30 or above as obese.

Why risk rises at a lower BMI in Asians

• Higher body fat at the same weight.
• A tendency toward visceral fat, which is stored deep in the abdomen around organs and drives insulin resistance, fatty liver, high triglycerides and high blood pressure.
• Lower muscle mass on average.
• Genetic and early-life factors, including low birth weight followed by rapid weight gain.
• Dietary patterns high in refined carbohydrate and sugar.

Waist size matters as much as BMI

Measure your waist halfway between the lowest rib and the top of the hip bone, after breathing out normally. For Asians, central obesity is suggested by:

• Men: waist of 90 cm (about 35.5 inches) or more
• Women: waist of 80 cm (about 31.5 inches) or more

Another useful number is the waist-to-height ratio. Keeping your waist below half your height is a simple rule that works across different body types.

Limits of BMI

BMI is a screening tool, not a diagnosis. It does not tell you how much fat you have or where it is stored. It may mislead in:

• Athletes and very muscular people, whose BMI may be high with little fat.
• Older adults, who lose muscle and may have a normal BMI but too much fat (sarcopenic obesity). Very low BMI in older age is also linked to poor outcomes.
• Pregnancy, where BMI is based on pre-pregnancy weight.
• Children and teenagers, where growth charts must be used.
• People with swelling or fluid retention.

When a result is borderline, your doctor may also check waist size, blood pressure, blood sugar and cholesterol.

What if your BMI is high?

1. Aim for a modest, achievable loss. Losing 5-10% of body weight improves blood sugar, blood pressure and cholesterol, and reduces fatty liver. Do not expect to reach the "ideal" weight overnight.
2. Check your calorie needs. Our TDEE calculator estimates how much energy you use each day. A small, sustainable deficit is better than extreme dieting.
3. Change the plate. Half vegetables, a quarter protein, a quarter starch. Cut sugary drinks and reduce fried snacks and sweets.
4. Move more. Aim for 150 minutes of brisk activity weekly plus strength training twice a week, and reduce long periods of sitting.
5. Sleep and stress. Poor sleep increases appetite and weight gain.
6. Get screened. Check blood sugar, blood pressure and cholesterol, especially if your BMI is 23 or more. See our guides on normal blood sugar levels and early symptoms of diabetes.

Avoid "miracle" supplements, very-low-calorie diets without supervision, and slimming teas. Ask your doctor about medical or surgical options if lifestyle change alone is not enough and you have obesity-related illness.

What if your BMI is low?

A BMI below 18.5 may reflect poor nutrition, chronic illness, thyroid disease, digestive disease, infection such as tuberculosis, eating disorders, depression or simply a small natural build. Unplanned weight loss deserves medical assessment. Include enough energy and protein, with regular meals and snacks, and see a doctor to look for a cause.

BMI in children

Children are compared with WHO growth charts. A child's BMI-for-age above the 85th percentile suggests overweight and above the 95th suggests obesity, but this must be interpreted by a doctor. For weight tracking in young children, try our child growth calculator.

When to see a doctor

See a doctor or dietitian if your BMI is 27.5 or above, or 23 and above with diabetes, high blood pressure, fatty liver, PCOS or a family history of heart disease. Also seek advice if your BMI is below 18.5, you are losing weight unintentionally, or you are worried about your relationship with food.

References

• WHO Expert Consultation: appropriate body-mass index for Asian populations, The Lancet, 2004
• WHO Western Pacific Region: the Asia-Pacific perspective on redefining obesity and its treatment
• International Diabetes Federation: waist circumference cutoffs for ethnic groups
• World Health Organization: obesity and overweight fact sheet