This article is part of South First's year-long Beat Obesity, Lower Diabetes (BOLD) series, an attempt to keep the lens steady, week-after-week analysis on what is changing, what is not, and what must.
Published Jan 08, 2026 | 7:00 AM ⚊ Updated Jan 08, 2026 | 7:00 AM
Obesity measurement. Representative image. (iStock)
Synopsis: For Indians, BMI>23, and a waist-to-height ratio of > 0.5 are better measures of obesity. Due to our propensity for abdominal fat, these parameters may tell us more about consequent cardiovascular risks.
In 1972, when nutrition researcher Ancel Keys popularised the Body Mass Index (BMI) formula, he was candid about its limitations. “BMI is not fully satisfactory,” he admitted. Still, he recognised it as a practical population-level tool.
Five decades later, BMI remains the global obesity standard: but the story of how we measure obesity has become far more complex, revealing a critical gap between a simple number and metabolic reality.
The BMI formula itself is deceptively straightforward: weight in kilograms divided by height in metres squared. However, this elegant simplicity masks a significant problem.
A person with a BMI of 25 could be an athlete with minimal body fat or an individual carrying dangerous visceral (abdominal) fat with metabolic dysfunction. Western medical systems largely overlooked this distinction for years, but India has forced a reckoning with this oversight.
In 2019-21, India’s National Family Health Survey (NFHS-5) made history by conducting the first national-level measurement of abdominal obesity using waist circumference.
The results were striking: 39.6% of Indian women had a waist circumference greater than 80 cm, a threshold indicating elevated cardiometabolic risk. Among men, 11.9% exceeded the 94-cm cutoff.
These numbers revealed something crucial that BMI alone had hidden: the distribution of fat matters more than total fat volume for predicting disease risk.
This shift reflects a paradigm change in obesity science. While the World Health Organisation maintained BMI cutoffs of 25 (overweight) and 30 (obese) for international comparison, Asian countries, including India, have adopted lower thresholds.
WHO Asia-Pacific guidelines recognise BMI ≥23 kg/m² as representing increased risk and BMI ≥25 as overweight.
The reasoning is compelling: Asian populations, particularly Indians, accumulate more visceral fat at lower BMI levels compared to Caucasians, resulting in cardiometabolic complications at BMI values considered “normal” by Western standards. One study of young adults in Mauritius found that Indians developed more adverse lipid profiles than people of African descent at identical BMI and waist circumference measurements — a finding explained only by the differential distribution of visceral-to-peripheral fat.
Beyond BMI and waist circumference, newer research highlights additional measurement strategies. The waist-to-height ratio (WHtR), calculated by dividing waist circumference by height, shows the strongest correlation with visceral fat in recent studies.
A WHtR exceeding 0.5 indicates significant metabolic risk. The 2024 European Association for the Study of Obesity moved even further, recommending that obesity diagnosis incorporate BMI, waist circumference measurement, metabolic assessment (lipids, glucose, blood pressure), and assessment of functional/ psychological impairments. This represents a shift from purely anthropometric classification to “adiposity-based chronic disease” diagnosis.
The anecdote often missed in medical education illustrates this perfectly: two patients, both with BMI 28 kg/m², walk into a clinic. One carries extra weight distributed over hips and thighs (protective fat); the other concentrates fat around the abdomen (hazardous fat). The protective peripheral fat has been shown to be metabolically beneficial, associated with better cardiovascular outcomes. The visceral fat actively secretes inflammatory cytokines that damage metabolic health. Conventional BMI would classify them identically.
In India specifically, this measurement evolution carries profound implications. The rapid urbanisation and economic development post-1991 accelerated the shift from undernutrition to overnutrition. However, many communities, particularly in rural areas, have not benefited equally from health-screening infrastructure that would enable waist circumference measurement.
Meanwhile, the higher threshold of metabolic risk in Indian populations means that screening protocols based on Western BMI cutoffs miss substantial numbers of at-risk individuals. An Indian adult with a BMI of 23 and a waist circumference of 82 cm (woman) technically falls within “normal” BMI range but meets criteria for abdominal obesity, a category with substantial cardiovascular risk.
The measurement challenge extends to accessibility. While advanced imaging (CT, MRI) can quantify visceral fat precisely, these technologies remain concentrated in urban centers and private facilities in India. The simplicity of waist circumference measurement, requiring only a tape measure, makes it pragmatic for resource-limited settings. Even this basic tool remains underutilised in primary care settings across India.
Looking ahead, the evolution of obesity measurement reflects a broader maturation of medicine: recognition that risk is heterogeneous, that ethnic and genetic factors shape disease presentation, and that one-size-fits-all metrics inadequately capture biological reality.
For India, this evolution offers both promise and challenge — promise that emerging therapeutic approaches can be precisely targeted to metabolically high-risk individuals earlier; challenge that screening infrastructure must evolve to enable this precision at scale.
(Edited by Majnu Babu).
