Manipal Hospital endocrinologist warns of hidden diabetes in lean Indians; why genes and diet both matter
The World Health Organisation (WHO) defines diabetes as a chronic, metabolic disease characterised by high blood glucose levels, which are caused by the body’s inability to produce enough insulin or to use it effectively.
This metabolic disease is often linked with obesity. However, now, an increasing number of lean Indians are also being diagnosed with diabetes, which is becoming a silent and often overlooked health risk.
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Dr Tejaswi V, consultant – diabetes and endocrinology, Manipal Hospital, Kanakapura Road, calls them ‘thin-fat Indians’, a term which was coined by Dr CN Yajnik. Dr Tejaswi, in an interview with HT Lifestyle, elaborated on why undetected diabetes in lean Indians is a risk, and why both genes and diet matter.

Why do genes and diet both matter in diabetes?
Dr Tejaswi highlighted that Dr Yajnik observed that, compared to Westerners, Indians weigh less and have higher body fat, particularly around the abdomen, known as visceral adiposity. This visceral fat highlights that body weight is not the only indicator of metabolic health.
The endocrinologist noted that our distinctive genetic makeup makes us more prone to insulin resistance, even at lower body weights. He further explained, “This inability to use insulin properly results in progressively higher blood sugar levels.”
According to Dr Tejaswi, certain gene variants can ‘predispose to both insulin resistance and accumulation of visceral fat instead of subcutaneous fat, which is a huge risk factor for diabetes even when the body mass index (BMI) appears normal.’ These genes are:
Epigenetic and early life influences
The Thrifty Phenotype Hypothesis offers a compelling explanation for a higher rate of diabetes and metabolic diseases among individuals who were undernourished in early life but later exposed to calorie-rich environments, Dr Tejaswi offers. “This intergenerational effect is common in India, where undernutrition in the past meets overnutrition in the present,” he added.

Modern diet and lifestyle triggers
Next, he pointed out that our dietary habits are now shifted to refined grains, sugar-sweetened beverages, and processed foods. “These foods cause rapid sugar spikes, and combined with sedentary lifestyles, they may accelerate insulin resistance in genetically susceptible individuals,” he warned.
Therefore, bq a decade earlier, Dr Tejaswi highlighted.
“It also explains why relying only on BMI underestimates the risk of metabolic dysfunction because of our lean phenotype,” he warned.
Lastly, he offered advice: “Recognising how genetics and diet interact can help individuals take steps toward better metabolic health. Therefore, we should prioritise appropriate lifestyle measures and regular screening, which can not only prevent lean diabetes from progressing, but also help in early detection and avoid its long-term complications.”
Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.
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