By Dr. Topoti Mukherjee, Lead Consultant – Nephrology & Kidney Transplant, Aster Whitefield Hospital

A new and concerning trend is emerging in clinical practice—individuals with normal body weight are increasingly being diagnosed with metabolic disorders due to hidden visceral fat.

For decades, body weight and Body Mass Index (BMI) have been the primary tools for assessing metabolic health. However, doctors are now cautioning that being thin does not necessarily equate to being healthy. Many individuals who appear lean externally may still carry harmful levels of internal fat, particularly in the abdominal region.

Understanding the Hidden Fat Problem

Visceral fat accumulates deep within the abdomen, surrounding vital organs such as the liver, pancreas, and kidneys. Unlike subcutaneous fat, it is metabolically active and releases inflammatory substances that disrupt normal bodily functions.

This condition—often referred to as the “thin-fat” phenotype—is characterized by normal body weight but high fat percentage and low muscle mass. It is increasingly being observed among South Asians, who tend to accumulate internal fat even at lower BMI levels.

Impact on Kidney Health

Medical experts highlight that visceral fat plays a critical role in triggering metabolic disorders that can damage kidney function. It contributes to insulin resistance, chronic inflammation, and hypertension—three key factors that progressively impair the kidneys’ filtration ability.

What makes this risk particularly dangerous is its silent progression. Early kidney damage often presents no visible symptoms, meaning individuals may remain unaware until the condition has advanced significantly.

Why Indians Face Higher Risk

South Asians are genetically predisposed to storing more visceral fat compared to many other populations. As a result, metabolic complications such as diabetes, fatty liver disease, and kidney damage can develop even when BMI falls within the “normal” range.

Importantly, BMI thresholds for Asian populations differ from global standards:

• 18.5–22.9 kg/m²: Normal
• 23–24.9 kg/m²: Overweight
• ≥25 kg/m²: Obese

This means health risks can emerge earlier—even when body weight appears acceptable.

Lifestyle factors further aggravate the issue. Diets high in refined carbohydrates, combined with low protein intake and sedentary habits, contribute to poor body composition. Increasingly, younger urban populations are experiencing muscle loss, which worsens metabolic health and promotes fat accumulation.

Looking Beyond BMI

Experts now stress the need to move beyond BMI as a sole diagnostic tool. More accurate indicators of metabolic health include:

• Waist circumference
• Waist-to-height ratio
• Body composition analysis

Regular health screenings—such as blood pressure checks, blood sugar tests, and kidney function assessments—are also essential, especially for individuals with a family history of metabolic disorders.

Early warning signs of kidney stress, such as slightly elevated creatinine levels or traces of protein in urine, often appear before noticeable symptoms.

Lifestyle Changes That Matter

Reducing visceral fat requires a shift in focus—from weight loss to metabolic health. Key strategies include:

• Regular physical activity: Strength training and resistance exercises help build muscle and improve insulin sensitivity
• Balanced nutrition: Diets rich in whole grains, lean proteins, fruits, vegetables, and healthy fats reduce inflammation
• Limiting processed foods: Reducing refined sugars, high-sodium foods, and ultra-processed meals
• Holistic habits: Adequate hydration, quality sleep, and stress management

Rethinking ‘Healthy Weight’

The concept of being “skinny but unhealthy” challenges long-standing assumptions about health and body weight. Increasingly, medical experts emphasize that metabolic health—not just weight—is the true indicator of well-being.

For many Indians, the real health risk lies beyond what is visible on the weighing scale. Recognizing the hidden impact of visceral fat and adopting preventive lifestyle measures are critical steps toward protecting long-term kidney health and preventing chronic disease.