Most people picture Type 2 diabetes as a disease that affects only overweight individuals. According to Dr Gagandeep Singh, MBBS, Founder, Redial Clinic, New Delhi, this is one of the most dangerous assumptions
in Indian healthcare and it is leading to delayed diagnoses.
“In my clinic, I see this situation frequently,” says Dr Singh. “A patient walks in with an HbA1c of 8.2%. They weigh around 65 kilograms, with a BMI of 22. Their previous doctor told them they couldn’t possibly be diabetic because they ‘don’t look the part.’ By the time they reach me, they’ve lost months sometimes years of the early intervention window.”
According to Dr. Singh, India has one of the highest rates of lean diabetes in the world. Studies estimate that 20–30% of Indians with Type 2 diabetes are not overweight by conventional BMI standards. The real issue, he explains, is not body weight but where fat is stored in the body.
The “Thin Outside, Fat Inside” Problem
Dr Singh emphasises that BMI alone is not an accurate indicator of metabolic health in the Indian population.
“BMI was never designed for the Indian body,” explains Dr Singh. “It was developed using European populations and measures only total body weight against height. It tells you nothing about body composition.”
He notes that an Indian man with a BMI of 23 may still carry dangerous levels of visceral fat fat that accumulates around organs such as the liver, pancreas, and intestines while appearing perfectly healthy on the outside.
For this reason, Dr Singh prefers tracking waist-to-height ratio instead of relying solely on BMI.
“A waist-to-height ratio above 0.5 is a red flag, regardless of what the weighing scale shows,” he says.
Visceral fat is particularly harmful because it is metabolically active. According to Dr. Singh, it directly contributes to insulin resistance by releasing free fatty acids into the bloodstream and triggering chronic low-grade inflammation in the body.
Why Standard Tests Miss It
Another challenge, Dr Singh says, is that routine diabetes screening often fails to detect early metabolic problems in lean individuals.
“The standard annual fasting glucose test is almost useless for catching this early,” Dr. Singh explains. “By the time fasting glucose levels become abnormal, metabolic damage has usually been developing for years.”
Instead, he recommends tests that measure insulin resistance more directly.
“Fasting insulin levels and HOMA-IR scores can identify the problem much earlier,” says Dr. Singh. “A fasting insulin level above 10 µIU/mL in a lean person should trigger further investigation rather than reassurance.”
At Redial Clinic, Dr Singh also uses continuous glucose monitoring (CGM) for some patients who appear metabolically healthy based on standard lab tests.
“The post-meal spikes we uncover in seemingly ‘normal’ individuals can be alarming,” he says. “Their fasting numbers may look fine, but their glucose levels can rise to 180–200 mg/dL after meals. Standard tests often fail to capture this.”
The Indian Diet Factor
According to Dr Singh, dietary patterns also play a major role in the rise of lean diabetes.
“A typical Indian vegetarian diet, heavy on rice, roti, and dal but low in protein is essentially a high-carbohydrate diet,” he says.
For individuals genetically predisposed to insulin resistance, Dr Singh explains that this macronutrient imbalance can worsen metabolic dysfunction.
“The issue isn’t that people are necessarily eating too much,” says Dr Singh. “It’s that they are consuming the wrong balance of nutrients.”
In his clinical practice, Dr. Singh often restructures patients’ diets by increasing protein intake and reducing refined carbohydrates.
“When patients consume 25–30 grams of protein per meal, reduce refined carbohydrates, and include healthy fats like ghee or olive oil, we start seeing improvements in metabolic markers within weeks,” he says. “Interestingly, this often happens even without any significant change in body weight.”
The Real Fix
For Dr Gagandeep Singh, lean diabetes is not a medical paradox but rather a problem of inadequate screening methods.
“We need to stop using BMI as the primary gatekeeper for metabolic health,” Dr. Singh says. “Instead, we should focus on measurements that truly matter, visceral fat levels, fasting insulin, and waist circumference.”
In India, he adds, being slim does not necessarily mean being metabolically healthy.
“The body you see in the mirror isn’t always the one making you sick,” says Dr Singh. “Often, it’s the fat you cannot see that poses the greatest risk.”
