Daijiworld Media Network - New Delhi

New Delhi, Mar 11: Doctors are increasingly warning that being thin does not always mean being healthy, as growing evidence shows that people with normal body weight can still develop serious metabolic diseases due to hidden internal fat.

Health experts say a rising number of patients, particularly in South Asia, are being diagnosed with metabolic disorders despite having a normal Body Mass Index. The problem is often linked to visceral fat, a type of fat that accumulates deep inside the abdomen around vital organs.

Visceral fat forms a layer around organs such as the liver, pancreas and kidneys. Unlike fat stored under the skin, it acts as a metabolically active tissue that releases inflammatory chemicals and disrupts normal organ function. This condition is often described as the “thin-fat” phenotype, where individuals appear slim but have higher internal fat and reduced muscle mass.

Doctors say the accumulation of visceral fat can lead to metabolic changes that eventually damage the kidneys. It contributes to insulin resistance, chronic inflammation and high blood pressure — all of which can gradually affect the kidneys’ microscopic filtering units and lead to Chronic Kidney Disease.

One of the major concerns, experts note, is that early kidney damage usually develops without noticeable symptoms. Many people only become aware of declining kidney function when the disease has already progressed to advanced stages.

South Asians are considered particularly vulnerable due to genetic and lifestyle factors. Studies show that people from the region tend to accumulate more visceral fat even when their body weight appears normal.

Medical experts say BMI standards for Asian populations differ slightly from global benchmarks. For Asians, a BMI between 18.5 and 22.9 kg/m² is considered normal, 23 to 24.9 kg/m² is classified as overweight and 25 kg/m² or higher is considered obese. Because metabolic complications often occur at lower body fat levels in Asian populations, diseases such as Type 2 Diabetes, fatty liver disease and kidney damage can develop earlier.

Lifestyle patterns also play a role. Diets high in refined carbohydrates but low in protein, combined with sedentary habits, can worsen body composition. Many people maintain a stable weight but lose muscle mass and gain internal fat, a trend increasingly observed among younger urban populations.

Doctors emphasise that BMI alone may not be sufficient to assess metabolic health. They recommend additional measures such as waist circumference, waist-to-height ratio and body composition analysis to better detect visceral fat.

Routine health screenings are also crucial, especially for individuals with a family history of metabolic disorders. Early signs of kidney stress may appear as slightly elevated creatinine levels or small amounts of protein in urine before symptoms become evident.

Experts say reducing visceral fat requires lifestyle changes focused on improving metabolic health rather than simply losing weight. Regular physical activity, particularly resistance training and muscle-strengthening exercises, can improve insulin sensitivity and increase muscle mass.

A balanced diet rich in whole grains, protein sources, vegetables, fruits and healthy fats can also help reduce inflammation and support metabolic function. Limiting refined sugars, processed foods and excessive salt intake is equally important for protecting kidney health.

Adequate hydration, good sleep and effective stress management further contribute to maintaining metabolic balance.

Health specialists say the growing recognition of the “skinny but unhealthy” phenomenon highlights the need to look beyond body weight when assessing disease risk. They stress that long-term kidney health depends more on metabolic fitness and healthy lifestyle habits than on numbers shown on the weighing scale.