Published Mar 02, 2026 | 7:00 AM ⚊ Updated Mar 02, 2026 | 7:00 AM
(L to R) Dr. Rakesh Kalapala, Dr. D Nageshwar Reddy and Dr. Nitin Jagtap of AIG Hospitals (Supplied)
Synopsis: The study’s central question was whether lifestyle choices could meaningfully alter the obesity risk conferred by genetics — and the answer, backed by data from nearly 7,000 people, is yes. Using polygenic risk scores — a method that aggregates the small effects of thousands of genetic variants to calculate inherited susceptibility — the researchers divided participants into four groups based on their combination of genetic risk and lifestyle.
Every time an Indian steps on a weighing scale and sees a number that looks acceptable, they may be walking away with a dangerous sense of safety.
A new study published in Scientific Reports, a peer-reviewed journal from the Nature portfolio, is challenging not just what Indians know about obesity — but what they think they are protected from.
The research, led by investigators at Hyderabad’s Asian Institute of Gastroenterology (AIG) in collaboration with researchers from the University of Luxembourg and the University of Marburg, Germany, examined how inherited genetic risk and lifestyle choices combine to determine obesity outcomes in people of Indian ancestry.
The findings, drawn from a dataset of 6,663 Indian-origin adults in the UK Biobank and 91 participants recruited across India, carry a message that is equal parts alarming and hopeful: your genes are not your destiny — but the window to act may be shorter than most people think.
When most Indians think of obesity, they think of the standard BMI cut off of 30 — the threshold used in Western medicine. But Indians are metabolically different. The body fat distribution, the genetic architecture, and the tendency to develop complications at lower body weights mean that the relevant cut off for Indians is a BMI of 23, not 30.
Apply that corrected standard, and the numbers shift dramatically. According to a recent ICMR study cited by the researchers, 40 percent of urban Indians fall into the overweight or obese category. In South India, truncal obesity — the dangerous accumulation of fat around the abdomen — runs as high as 46 percent. Meanwhile, the country’s obesity rate has doubled in ten years, from roughly 15 percent in 2015 to over 30 percent today.
“Indians are having metabolic complications with much lower BMI. If you have obesity, the chance of diabetes, chance of fatty liver, chance of heart attacks, chance of high cholesterol are very high,” said Dr D Nageshwar Reddy, Chairman, AIG Hospitals.
There is a simple self-check that requires no equipment: measure your waist at the level of your navel. If that number in centimetres is more than half your height in centimetres, you have truncal obesity — regardless of what your weighing scale says.
The study’s central question was whether lifestyle choices could meaningfully alter the obesity risk conferred by genetics — and the answer, backed by data from nearly 7,000 people, is yes. Using polygenic risk scores — a method that aggregates the small effects of thousands of genetic variants to calculate inherited susceptibility — the researchers divided participants into four groups based on their combination of genetic risk and lifestyle.
Those with high genetic risk and an unhealthy lifestyle showed an odds ratio of 24.51 for obesity in the India cohort. Those with the same high genetic risk but a healthy lifestyle showed dramatically lower odds.
“Even if you have genetic abnormality, if you have a favourable lifestyle — correct diet, adequate exercise, no smoking — you would not become obese. You can control it,” Dr Reddy said.
The gap between Indians in India and Indians living in the UK, who share the same genetic background, tells its own story. In the UK cohort, the odds ratio for the same high-risk, unhealthy-lifestyle group was 3.01. In India, it was 24.51. Eight times higher. Same genes, same hereditary risk — the only variable is the environment and lifestyle that surrounds them.
Perhaps the most urgent finding in the study is one that received the least attention: age matters enormously. The study’s age-stratified analysis found that lifestyle interventions are significantly more effective in people below the age of 50.
After 60, a condition called sarcopenia — the progressive wasting of muscle mass — begins to set in, and the body’s ability to respond to lifestyle changes diminishes substantially.
“Above the age of 60, it is very difficult to modify. The body has lost a lot of plasticity. If you want to modify, do it early. Below 50, you can build muscle very easily and fat comes down,” Dr Reddy said.
“The prescription for those still within that window is specific: 150 minutes of exercise per week, split equally between aerobic activity and muscle-strengthening exercises. A practical marker for aerobic intensity — you should be able to talk during brisk walking, but not sing. And perhaps most counterintuitively, avoiding artificial sweeteners matters too.”
“Ultra-processed food, chips, noodles, burgers — these have preservatives, colouring agents, and additives that destroy the gut microbiome,” Dr Reddy said. “Even sugar-free products — if you want a little sugar, take sugar. Do not take artificial sweeteners. They damage the microbiome more than sugar itself.”
If the findings carry one warning that extends beyond the individual, it is this: parental obesity is now a quantifiable, genomically -backed risk factor for the next generation. Dr Nitin Jagtap, gastroenterologist and co-author of the study, presented a number that reframes the entire conversation.
“Obesity in children has quadrupled. The risk is four times higher if parents are obese. Parental obesity is having a detrimental effect on our future,” he said.
At a time when school surveys are finding fatty liver and obesity in 30 to 40 percent of children, the researchers are emphatic that intervention must begin early — at the school level, at the family level, and ideally before the first warning sign appears. “At this stage, if parents and school teachers can change the lifestyle of children, although they are genetically prone to obesity, they become healthy,” Dr Reddy said.
The researchers are candid about the study’s limitations. The lifestyle data is self-reported, the India cohort of 91 participants requires expansion, and the cross-sectional design means the study establishes association, not causation. The polygenic risk scores were also built substantially on European genomic data — a constraint the authors acknowledge given India’s distinct genetic architecture.
What the study does establish — for the first time in an Indian population at this scale — is that the interaction between genetic risk and lifestyle is real, measurable, and modifiable. AIG’s own microbiome laboratory is already working on the next layer of questions: how gut bacteria, sleep, stress, and diet quality interact with genetic predisposition in Indians specifically.
For now, the message is unambiguous: get your waist measured, not just your weight. Move before 50. And understand that the choices you make today are not just yours — they are being inherited.
(Edited by Sumavarsha)
