Archive · 26 Aug 2026
Lean Adults Can Develop Fatty Liver Despite Normal BMI
A person can look thin and still have too much fat around their organs.
This fat can collect in the liver and cause fatty liver disease.
Arun was 44 and had a normal BMI, but his waist was larger and his blood sugar and triglycerides were high.
He also had little muscle and did not exercise regularly.
These signs showed that his body was not as metabolically healthy as it appeared.
Doctors checked whether his liver had started to become stiff from scarring.
Healthy eating, exercise and treatment for blood sugar and cholesterol can help.
For lean people, building muscle and reducing harmful abdominal fat may matter more than simply losing weight.
A 44-year-old executive with a BMI of 22.6 was diagnosed with lean MASLD after an ultrasound found fatty liver.
His enlarged waist, elevated triglycerides and prediabetes indicated metabolic risk despite his thin appearance.
BMI cannot show abdominal fat, low muscle mass or fat stored in organs such as the liver.
Fibrosis assessment is important because normal or mildly raised liver enzymes may not exclude liver scarring.
Treatment should target visceral fat and insulin resistance while preserving muscle, rather than focusing only on weight loss.
- Who
- Arun, a 44-year-old executive, illustrates the issue; lean adults, particularly in Asian populations, can also develop lean MASLD.
- What
- Fatty liver was detected in a person with a normal BMI, leading to a diagnosis of lean metabolic dysfunction-associated steatotic liver disease.
- When
- The article does not provide a date; Arun’s condition was identified at age 44.
- Where
- The case was assessed in a clinic, and the article discusses Asian populations and India.
- Why
- Abdominal fat, metabolic abnormalities, low muscle mass and lifestyle factors can cause liver fat even when overall body weight appears normal.
- BMI in the case
- 22.6 kg/m², within the lean range cited for an Asian adult.
- Waist-risk threshold
- In South Asians, waist circumference of 90 cm or more in men and 80 cm or more in women suggests central adiposity.
- Relevant metabolic findings
- Arun had a 93 cm waist, elevated triglycerides and HbA1c in the prediabetes range.
- Fibrosis screening
- FIB-4 uses age, AST, ALT and platelet count as an initial assessment.
- FIB-4 guidance
- Below 1.3 generally indicates low risk; 1.3–2.67 usually calls for elastography; above 2.67 warrants specialist evaluation.
- Exercise recommendation
- At least 150 minutes of aerobic activity weekly plus resistance training on two or more days.
- Dietary approach
- Reduce portions of polished rice, refined flour, sweets, fruit juice and sugary drinks while adding vegetables, pulses and appropriate protein.