The study found that individuals with higher genetic obesity risk responded well to diet and exercise, but also regained weight faster once interventions stopped, highlighting a complex gene-lifestyle interaction
Published Jul 23, 2025 | 7:00 AM ⚊ Updated Jul 23, 2025 | 7:00 AM
Representative pic of an obese boy. (Wikimedia Commons)
Synopsis: Scientists at CSIR-CCMB, Hyderabad, have helped develop the world’s most accurate genetic test to predict obesity risk in children as young as five. Led by Dr. Giriraj Ratan Chandak, the team contributed critical South Asian genetic data to a global study published in Nature Medicine, analyzing genomes of individuals tracked for nearly 20 years, including those with and without diabetes
Scientists at the CSIR-Centre for Cellular and Molecular Biology (CSIR-CCMB) have played a crucial role in developing the world’s most accurate genetic test for predicting obesity risk in children as young as five years old, as part of a landmark international study published in Nature Medicine.
Led by Dr. Giriraj Ratan Chandak at CSIR-CCMB, the Hyderabad-based research team characterized genomes from the Indian population to contribute vital South Asian genetic data to the global research effort. Their work involved analyzing individuals with diabetes as well as those with normal blood glucose levels who have been tracked for nearly two decades.
“The observations made from this study are similar to the earlier results on height, where genetic variants identified in Europeans, predicted lower risk in Indians and environment-related modifications of genes play a larger role,” said Dr. Chandak. “It looks like lifestyle, diet and nutrition might be playing an equal or more important role in predicting obesity in Indians.”
The Indian contribution was particularly significant given that obesity patterns in India differ markedly from those in Europe, with Indians tending to develop more central (abdominal) obesity. Previous studies by Dr. Chandak had already established that the genetic basis of non-communicable diseases varies significantly between Indians and Europeans.
The research is especially relevant for India and South Asia, where obesity poses a grave health challenge due to higher incidences of diabetes, hypertension, and cardiovascular diseases. The Indian genomic data served as representative for the entire South Asian population in the study, making the findings more applicable to over 1.4 billion people in the region.
Despite the inclusion of more diverse genetic data, the polygenic risk score (PRS) still predicted obesity more accurately in people with European ancestry than in those with South Asian ancestry, including Indians. This finding underscored the importance of population-specific genetic research.
The international study, involving 600 researchers across 500 institutions, utilized the largest and most diverse genetic dataset ever assembled, including data from over five million people worldwide. The team drew on genetic information from the GIANT consortium and consumer DNA testing company 23andMe.
The resulting polygenic risk score is twice as effective as previous tests at predicting obesity risk and can identify children at higher genetic risk around age five—well before other risk factors begin influencing weight in later childhood.
“What makes the score so powerful is its ability to predict, around the age of five, whether a child is likely to develop obesity in adulthood, well before other risk factors start to shape their weight later in childhood. Intervening at this point can have a huge impact,” said Assistant Professor Roelof Smit from the University of Copenhagen, the study’s lead author.
The research also revealed important insights about the relationship between genetic risk and lifestyle interventions. Individuals with higher genetic risk of obesity responded better to diet and exercise interventions but also regained weight more quickly once the interventions ended.
For the Indian population specifically, the findings suggest that lifestyle solutions and targeted nutrient supplementation, considered alongside genetic risk, might yield better results than genetic predictions alone.
The study comes at a critical time, as the World Obesity Federation predicts that more than half of the global population will be overweight or obese by 2035. Obesity increases the risk of non-communicable diseases including diabetes, cardiovascular diseases, poor bone health, reproductive problems, and various cancers.
The new genetic test could help identify children and adolescents at higher risk who would benefit from targeted preventive strategies and lifestyle interventions at a younger age, potentially helping to curb the growing global obesity epidemic.
The research demonstrates that while genetics play an important role in obesity risk, lifestyle factors remain crucial—particularly for populations like Indians where environmental and dietary factors may have an even greater impact than genetic predisposition.
(Edited by Ananya Rao)
