Think You’re Safe from Fatty Liver? Normal Weight Doesn’t Guarantee Risk-Free Liver Health

Fatty liver disease, now often termed metabolic dysfunction–associated steatotic liver disease (MASLD), is usually associated with obesity, diabetes, and alcohol intake. However, an increasing number of cases are being reported among individuals with normal body weight and no history of excessive alcohol consumption. This condition is referred to as lean fatty liver disease or lean NAFLD.

A case reported by The Indian Express describes a 28-year-old woman in Delhi who developed fatty liver disease despite maintaining a normal body weight and no history of alcohol use. Initially, she was misdiagnosed with Type 1 diabetes, which complicated her clinical management before her condition was correctly identified.

The woman, Nishi Gupta (name changed), a PhD scholar, had a body mass index within the healthy range (5′3″ and 61 kg). She sought medical attention after experiencing severe abdominal pain. Tests revealed that her liver enzymes, SGOT and SGPT, were abnormally high—between 600–700 U/L, compared to the normal range of 7–56 U/L. Further investigations confirmed nonalcoholic fatty liver disease (NAFLD), now clinically referred to as metabolic dysfunction–associated steatotic liver disease (MASLD).

Her medical history revealed that she had been diagnosed with diabetes as a teenager after fainting episodes and recurrent hypoglycemia-like symptoms. Based on her presentation, she was assumed to have type 1 diabetes and was placed on insulin therapy. Later evaluation showed her diabetes type was misclassified, and the metabolic dysfunction likely contributed to the development of fatty liver.

Lean NAFLD: Not Just a Disease of Obesity

While fatty liver disease is strongly associated with obesity, a significant number of patients develop it despite having a normal body mass index, a condition termed lean NAFLD.

• A 2023 study from India comparing lean and non-lean NAFLD patients found that disease severity, including fibrosis and steatohepatitis, was comparable between the two groups. ²

• Reviews note that lean NAFLD patients often present with fewer classical metabolic risk factors, yet still experience disease progression. ³

• Factors implicated include genetic predisposition, subtle insulin resistance, lipotoxicity, and adipose tissue dysfunction. ⁴

Why Lean Individuals Develop Fatty Liver

The mechanisms behind lean fatty liver disease are still being studied, but several factors are believed to contribute:

• Genetic predisposition: Variants in genes such as PNPLA3 have been linked with higher risk.

• Metabolic dysfunction: Even in the absence of obesity, subtle insulin resistance and lipid imbalances can trigger fat accumulation in the liver.

• Visceral fat: Individuals with a normal body mass index (BMI) may still carry higher levels of visceral fat around abdominal organs, increasing metabolic risk.

• Dietary patterns and lifestyle: High sugar intake, sedentary habits, and poor sleep have been associated with fatty liver across weight categories.

A 2023 Indian study found that lean patients with fatty liver had fewer classical metabolic risk factors compared to obese patients, yet their liver damage could be equally severe, with comparable risk of steatosis and fibrosis progression. ²

Misdiagnosis and Diagnostic Challenges

This case illustrates the challenge in identifying fatty liver disease in people without obesity. Because obesity is the most common clinical marker, lean patients may not be screened early. Additionally, misclassification of diabetes type, as in Gupta’s case may delay recognition of underlying metabolic dysfunction.

According to research, NAFLD can both contribute to and result from insulin resistance. ⁵ This bidirectional relationship makes accurate diagnosis essential. Experts recommend that patients with unexplained elevated liver enzymes undergo imaging studies such as ultrasound or FibroScan, along with blood work for metabolic markers, even if they are of normal weight.

Clinical and Public Health Relevance

• Screening criteria: Physicians may need to expand fatty liver screening to include individuals who are lean but present with abnormal liver enzymes or metabolic indicators.

• Correct diabetes typing: Misclassification between type 1 and type 2 diabetes can obscure the presence of metabolic syndrome, delaying targeted therapy.

• Lifestyle and monitoring: Lean NAFLD patients may benefit from structured dietary changes, exercise, and ongoing metabolic monitoring.

• Research need: More studies are required to evaluate progression risk and effective interventions in lean NAFLD.

References

1. The Indian Express. “28-Year-Old Has Fatty Liver Despite Normal Body Weight: What Was Her Trigger?” The Indian Express, September 29, 2025. https://indianexpress.com/article/health-wellness/28-year-old-has-fatty-liver-despite-normal-body-weight-what-was-her-trigger-10283135/.

2. Mohan, B., A. Duseja, et al. “Lean Non-Alcoholic Fatty Liver Disease: Clinical and Histological Profile in Comparison with Obese NAFLD Patients.” Journal of Clinical and Experimental Hepatology 13, no. 4 (2023): 1192–1200. https://pubmed.ncbi.nlm.nih.gov/37474570/.

3. Ye, Q., J. Zou, et al. “Lean Non-Alcoholic Fatty Liver Disease: An Underrecognized and Challenging Condition.” Hepatology International 14, no. 6 (2020): 799–813.

   https://pmc.ncbi.nlm.nih.gov/articles/PMC5606968/.

4. Kim, D., and Z. Younossi. “Epidemiology and Risk Factors of Nonalcoholic Fatty Liver Disease in Lean Individuals.” Nutrients 17, no. 11 (2023): 1797. https://www.mdpi.com/2072-6643/17/11/1797.

5. Vilar-Gomez, E., Cusi, K., et al. “Nonalcoholic Fatty Liver Disease and Type 2 Diabetes Mellitus: Pathophysiology and Management.” Endocrine Reviews 43, no. 1 (2022): 55–96. https://pmc.ncbi.nlm.nih.gov/articles/PMC11725303/.

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