He had fatty liver at 44 despite being thin: Why being lean may not be enough

Arun, a 44-year-old executive, visited the clinic with an ultrasound report revealing fatty liver. Surprised by the diagnosis, he noted that he wasn't overweight, with a BMI of 22.6 kg/m². Despite his seemingly healthy appearance, his waist measured 93 cm, his triglycerides were elevated, and his HbA1c was in the prediabetes range.

A desk job, frequent rice and refined cereal consumption, irregular exercise, and low muscle mass contributed to his condition. He was diagnosed with lean metabolic dysfunction-associated steatotic liver disease (lean MASLD), highlighting that thinness doesn't equate to metabolic health. The definition of "lean" differs based on ethnicity, with South Asians considered lean at a BMI below 23 kg.

Arun's case exemplifies how fatty liver can be overlooked due to its association with obesity. BMI doesn't account for where fat is stored or muscle mass, making it possible for two individuals with the same BMI to have different metabolic profiles. Visceral and ectopic fat around organs triggers insulin resistance, inflammation, and the release of fatty acids, contributing to metabolic dysfunction.

In South Asians, a waist circumference of 90 cm or more in men and 80 cm or more in women signals central adiposity. Blood tests and liver elastography can identify liver fibrosis, which can progress to cirrhosis or liver cancer. For lean individuals with MASLD, assessing for fibrosis and addressing factors like waist circumference, blood pressure, glucose levels, and lifestyle habits are crucial.

Treating lean MASLD involves reducing visceral fat, improving insulin sensitivity, and preventing further muscle loss through dietary and lifestyle modifications.