Understanding BMI: A Complete Guide for Indians

What Is BMI and Why Does It Matter?

Body Mass Index (BMI) is a simple numerical measure that uses your height and weight to estimate whether you fall into a healthy weight range. Doctors worldwide use it as a screening tool to identify potential weight-related health risks.

While BMI is not a perfect measure (more on its limitations below), it remains one of the most widely used and accessible tools for understanding your weight status. For Indians especially, understanding BMI is critical — because the standard thresholds used globally do not apply to South Asian bodies.

How to Calculate Your BMI

The BMI formula is straightforward:

BMI = Weight (kg) / Height (m) x Height (m)

For example, if you weigh 75 kg and your height is 1.68 m (5 feet 6 inches):

• BMI = 75 / (1.68 x 1.68)
• BMI = 75 / 2.8224
• BMI = 26.6

Under global WHO standards, a BMI of 26.6 is classified as "overweight." But for Indians, as we will discuss, this number carries significantly greater health implications.

Standard WHO BMI Categories

The World Health Organization defines the following BMI categories for the general global population:

• Below 18.5 — Underweight
• 18.5 to 24.9 — Normal weight
• 25.0 to 29.9 — Overweight
• 30.0 and above — Obese

These thresholds were developed primarily using data from European populations. For decades, these same numbers were applied universally — but research has shown that they significantly underestimate risk for South Asian populations.

Why Indian BMI Thresholds Are Different

This is the most important section of this article. Indians and other South Asians develop serious health complications at lower BMI levels than Europeans. This is not a minor difference — it is clinically significant and well-documented.

Key findings from research published in The Lancet and endorsed by WHO Asia-Pacific guidelines:

• Indians carry higher body fat percentage at the same BMI compared to Europeans — roughly 3-5% more body fat at any given BMI
• Indians accumulate more visceral fat (fat around internal organs) even at lower BMIs, which is the most metabolically dangerous type of fat
• Insulin resistance, type 2 diabetes, and cardiovascular disease emerge at significantly lower BMIs in South Asians
• AIIMS and ICMR research confirms that metabolic syndrome is prevalent in Indians with BMIs as low as 23

Based on this evidence, the revised BMI thresholds for Indians recommended by WHO Asia-Pacific guidelines and adopted by many Indian health institutions are:

• Below 18.5 — Underweight
• 18.5 to 22.9 — Normal weight
• 23.0 to 24.9 — Overweight (at risk)
• 25.0 and above — Obese

Notice the difference: the overweight threshold for Indians is 23, not 25. The obese threshold is 25, not 30. This means millions of Indians who believe they are at a "normal" weight based on global standards are actually in the overweight or obese category by Indian-specific criteria.

Going back to our earlier example — a person with a BMI of 26.6 would be classified as merely "overweight" by global standards but is firmly in the obese category by Indian standards, carrying meaningful cardiometabolic risk.

What Your BMI Means for Your Health

For Indians, here is what each BMI range generally indicates:

BMI Below 18.5 — Underweight

May indicate nutritional deficiency, malabsorption, or other underlying health conditions. Consult a doctor if you are consistently underweight, especially if you have experienced unintended weight loss.

BMI 18.5 to 22.9 — Normal Weight

This is the healthy range for most Indians. Focus on maintaining this through balanced nutrition and regular physical activity. Continue monitoring annually.

BMI 23.0 to 24.9 — Overweight (At Risk)

You are carrying excess weight that increases your risk for type 2 diabetes, hypertension, and cardiovascular disease. Lifestyle modifications — dietary changes, increased physical activity, stress management — are strongly recommended. Consider consulting a doctor for a metabolic health check.

BMI 25.0 and Above — Obese

At this level, health risks increase significantly. ICMR data shows that Indians with a BMI above 25 have a two to three times higher risk of developing type 2 diabetes compared to those in the normal range. Medical evaluation and supervised weight management are recommended.

Limitations of BMI

While BMI is a useful screening tool, it has important limitations that you should understand:

• Does not distinguish between fat and muscle — A muscular person may have a high BMI without excess fat. This is common in athletes and people who do regular strength training.
• Does not indicate fat distribution — Where you carry fat matters enormously. Visceral fat (around your abdomen and organs) is far more dangerous than subcutaneous fat (under the skin on arms and legs).
• Does not account for age or gender — Body composition changes with age, and women naturally carry more body fat than men at the same BMI.
• Less reliable at extremes — BMI is least accurate for very tall individuals, very short individuals, and the elderly.

For these reasons, doctors often use BMI alongside other measurements to get a complete picture of metabolic health.

Waist Circumference: The Measurement That Complements BMI

Waist circumference is an excellent indicator of visceral fat — the type of fat most strongly linked to metabolic disease. For Indians, the recommended thresholds are:

• Men: waist circumference above 90 cm (35.4 inches) indicates elevated risk
• Women: waist circumference above 80 cm (31.5 inches) indicates elevated risk

These thresholds are lower than the global standards (102 cm for men, 88 cm for women), again reflecting the higher metabolic risk South Asians face at lower measurements.

To measure correctly: use a tape measure around your bare abdomen, just above the hip bone, at the level of your navel. Measure after exhaling normally. Do not pull the tape tight.

If your BMI is in the overweight or obese range and your waist circumference exceeds these thresholds, the combination indicates significantly elevated cardiometabolic risk that warrants medical attention.

When to Seek Medical Help

Consider consulting a doctor for weight management if:

• Your BMI is 23 or above (Indian threshold for overweight)
• Your waist circumference exceeds 90 cm (men) or 80 cm (women)
• You have a family history of diabetes, heart disease, or obesity
• You have tried multiple diets without sustainable results
• You have existing conditions like PCOS, thyroid disorders, or pre-diabetes that may be contributing to weight gain
• You experience symptoms like excessive fatigue, joint pain, sleep apnoea, or irregular periods that may be related to weight

Check Your BMI and Talk to a Doctor on NuvaHealth

Understanding your BMI is the first step. The next step is taking action based on what those numbers mean for your individual health.

At NuvaHealth, we connect you with licensed doctors who understand South Asian metabolic health. Through a video consultation from home, your doctor can assess your complete metabolic profile — BMI, waist circumference, blood work, family history — and create a personalised plan that accounts for your unique biology.

No generic advice. No one-size-fits-all plans. Just evidence-based medical care designed for Indian bodies.

Start your assessment on NuvaHealth and take control of your metabolic health today.