The Surprising 'Normal Weight' Problem
The ICMR-INDIAB study, a massive cross-sectional survey covering over 113,000 people across India, has unveiled a startling paradox. A huge percentage of the population falls into a category called 'Metabolically Obese Normal Weight' (MONO). This means
that while their Body Mass Index (BMI) is in the 'normal' range, they exhibit at least two risk factors for metabolic disease, such as high blood pressure, elevated blood sugar, high triglycerides, low 'good' HDL cholesterol, or a large waist circumference. The study found that this MONO group is the largest obesity subtype in India, accounting for a staggering 43.3% of the population. In contrast, only 26.6% of Indians were found to be both non-obese and metabolically healthy.
Why BMI Is a Flawed Messenger
Body Mass Index (BMI) is a simple calculation of weight in relation to height. While easy to measure, it has significant limitations, especially for the Indian population. A key issue is that BMI does not distinguish between fat and muscle. More importantly, it doesn't account for body fat distribution. South Asians have a genetic predisposition, often called the 'Asian Indian Phenotype', to store more visceral fat—fat that wraps around abdominal organs—even at a lower BMI compared to other ethnic groups. This hidden internal fat is metabolically active and a major driver of insulin resistance, type 2 diabetes, and heart disease, making someone 'thin on the outside, fat on the inside' (TOFI).
The Tape Measure Tells a Truer Story
Given the limitations of BMI, the ICMR study and other health bodies now emphasize a more reliable indicator: waist circumference. A simple measuring tape can reveal the presence of harmful abdominal obesity. For the Indian population, the recommended healthy waist circumference is less than 90 cm (about 35 inches) for men and less than 80 cm (about 31.5 inches) for women. Exceeding these limits is a strong warning sign of increased risk for non-communicable diseases (NCDs), regardless of what the weighing scale says. The INDIAB study found that abdominal obesity is rampant, with an estimated 351 million Indian adults affected.
Understanding the Four Health Profiles
The ICMR-INDIAB study categorised people into four groups to better understand the link between weight and metabolic health. The largest group was 'Metabolically Obese Normal Weight' (MONO), who are at high risk for conditions like chronic kidney disease. The next was 'Metabolically Obese Obese' (MOO), who have both a high BMI and poor metabolic markers, putting them at the highest risk for type 2 diabetes and coronary artery disease. A smaller group was 'Metabolically Healthy Non-Obese' (MHNO), the ideal healthy state. Finally, the smallest group was 'Metabolically Healthy Obese' (MHO), individuals who are obese by BMI but do not have metabolic risk factors. However, research suggests this 'healthy obese' state is often temporary.
What This Means for Your Health
The study's conclusions are clear: focusing solely on weight loss is a flawed strategy for health improvement in India. It highlights the urgent need to shift focus from just BMI to a broader set of metabolic health markers. This doesn't mean weight is irrelevant, but that it should be considered alongside waist measurement, blood pressure, fasting blood sugar, and cholesterol levels. Another part of the ICMR-INDIAB research points to diet, noting that Indian diets are often excessively high in carbohydrates (62% of calories) and low in protein (12%), a combination that fuels metabolic risk. Making small dietary changes, like replacing some carbohydrate calories with protein, can significantly lower the risk of diabetes.
