Why more young Indians are being diagnosed with diabetes despite not being overweight

For years, diabetes has carried a certain image. Many people picture someone who is overweight, inactive, and visibly struggling with unhealthy lifestyle habits. It is a belief so deeply rooted that countless young Indians who appear slim and fit rarely consider themselves at risk.

Yet doctors across the country are witnessing a different reality. Increasingly, young adults with normal body weight are being diagnosed with diabetes, often during routine health checks or after symptoms that seemed too minor to worry about. The diagnosis comes as a shock because they do not fit the stereotype.

The question is no longer whether diabetes can affect lean individuals. The real question is why it is happening so often in India.

One of the biggest misconceptions about health is that a normal Body Mass Index (BMI) automatically means a healthy body.

According to Dr Supratik Bhattacharyya, Senior Consultant – Diabetes, Endocrinology & Obesity at Manipal Hospital, Broadway & Salt Lake, the picture is far more complex, “Many people still believe diabetes only affects individuals who are overweight but in India, we frequently see ‘skinny diabetics’ or lean individuals developing diabetes despite appearing thin externally,” he says.

​Researchers have long observed what experts call the South Asian metabolic phenotype or the "thin-fat" phenomenon. In simple terms, many Indians tend to store fat differently from Western populations. Instead of accumulating fat under the skin, they often store more fat around internal organs, particularly the abdomen and liver.

This means a person may wear the same clothing size for years, maintain a normal BMI, and still develop metabolic problems that increase diabetes risk.

A large national study conducted under the Indian Council of Medical Research project has repeatedly highlighted the growing burden of diabetes across India and the need to look beyond traditional risk markers.

When most people think of body fat, they think of what they can see in the mirror.

However, doctors are often more concerned about what cannot be seen.

Fat surrounding the liver, pancreas, and abdominal organs can interfere with how the body uses insulin. This type of fat can trigger inflammation, worsen blood sugar control, and increase the risk of diabetes even in people who look slim.

Dr Bhattacharyya explained, “This reflects the unique South Asian metabolic phenotype, where a person may have relatively low BMI but still carry excess abdominal or liver fat, reduced muscle mass, and significant metabolic dysfunction.”

Modern lifestyles are making the problem worse. Many young adults spend long hours sitting, experience chronic stress, sleep poorly, and consume diets rich in refined carbohydrates. A person may not gain visible weight, but these habits can gradually damage metabolic health.

Another reason diabetes is appearing in lean individuals is that not all forms of the disease develop in the same way.

For some people, the issue is not severe insulin resistance caused by excess body fat. Instead, the pancreas may simply fail to produce enough insulin.

Dr Bhattacharyya pointed out, “In fact, some lean individuals belong to diabetes clusters characterized by insulin deficiency or insulinopenia rather than classic obesity-driven insulin resistance.”

This distinction matters because treatment approaches may differ significantly.

Genetics may also play a major role. South Asians are known to have a higher inherited susceptibility to diabetes compared with many other populations. When genetic vulnerability combines with poor sleep, stress, physical inactivity, and unhealthy dietary patterns, diabetes can develop earlier than expected.

In many cases, the disease begins silently years before symptoms become noticeable.

Perhaps the biggest danger is not the disease itself but the delay in recognising it.

When a young person appears healthy and maintains a normal weight, neither they nor their family members may suspect diabetes. Even healthcare providers may initially look for other explanations for symptoms.

Dr Bhattacharyya highlighted this challenge, “One of the biggest challenges is delayed diagnosis because these patients do not fit the stereotypical image of diabetes.”

As a result, warning signs such as excessive thirst, frequent urination, fatigue, weakness, blurry vision, or unexplained weight changes may be ignored.

He also stresses that doctors must carefully determine the exact type of diabetes involved.

“It is also extremely important to evaluate whether the patient may actually have autoimmune diabetes such as Type 1 diabetes (T1D) or latent autoimmune diabetes in adults (LADA),” said Dr Bhattacharyya.

“Testing for pancreatic autoantibodies and assessing endogenous insulin reserve can help differentiate these conditions early and guide appropriate treatment.”

This is particularly important because some adults initially diagnosed with Type 2 diabetes may actually have autoimmune forms of diabetes that require a different treatment strategy.

The good news is that experts are increasingly moving away from focusing solely on body weight.

A person can be thin and unhealthy, just as someone can carry extra weight and have better metabolic health. What matters is the overall functioning of the body's systems.

For individuals with Type 1 diabetes or LADA, treatment often relies on insulin.

As Dr Bhattacharyya explained, “The cornerstone of management in Type 1 diabetes and LADA is insulin therapy, either through multiple daily insulin injections or insulin pump therapy along with regular blood glucose monitoring or continuous glucose monitoring wherever feasible.”

But diabetes care today extends far beyond medication.

“Equally important is individualized medical nutrition therapy tailored to the patient’s metabolic profile and lifestyle,” he added.

Doctors now assess waist circumference, liver health, muscle mass, nutrition status, sleep quality, and other metabolic risk factors rather than relying solely on BMI.

Dr Bhattacharyya further noted, “Management goes far beyond simply lowering glucose. We carefully assess waist circumference and abdominal obesity even in thin individuals, along with liver health, muscle mass, nutrition, and metabolic risk factors.”

He added, “Medical nutrition therapy plays a central role, particularly diets rich in high-quality protein and fibre to preserve muscle health, improve insulin sensitivity, and reduce glucose variability. Strength training, correction of micronutrient deficiencies, adequate sleep, stress management, and holistic metabolic care are equally important.”

This shift reflects a growing understanding that diabetes is not simply a disease of excess weight. It is a disease of metabolic imbalance.

This article includes expert inputs shared with TOI Health by:

Dr Supratik Bhattacharyya, Senior Consultant – Diabetes, Endocrinology & Obesity at Manipal Hospital, Broadway & Salt Lake.

Inputs were used to examine why an increasing number of young Indians with normal body weight are developing diabetes, highlighting the role of hidden metabolic risks, genetic predisposition, insulin deficiency, abdominal fat accumulation, and the importance of looking beyond body weight when assessing diabetes risk.