Fatty liver disease (MASLD and MASH)

Also known as:

Metabolic dysfunction-associated steatotic liver disease, formerly NAFLD and NASH

Fat in the liver driven by metabolic risk. Common, silent and now treatable when inflammation and scarring develop.

Written and reviewed by Farhan Tahir, MD · Last reviewed

Nov 9, 2026

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IN THE STUDIO

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ANIMATED EXPLAINER · FATTY LIVER

STEP 1 OF 5

Fat overflows

Excess energy and insulin resistance push fat into the liver.

What it is

MASLD is fat in the liver plus at least one cardiometabolic risk factor such as obesity, diabetes, high blood pressure or abnormal lipids. In 2023 it replaced the term NAFLD. MASH is the inflammatory form that can scar the liver (fibrosis) and progress to cirrhosis.

How it's diagnosed

Often found on imaging or mildly abnormal liver tests. Guidelines use the FIB-4 score, from age, liver enzymes and platelets, to estimate fibrosis risk, followed by elastography (such as FibroScan) when the score is not low.

Treatment

Weight loss is the foundation: losing about 7% to 10% of body weight improves liver fat and inflammation, and larger losses can improve fibrosis. Resmetirom was FDA-approved in 2024 and semaglutide in 2025 for MASH with moderate to advanced fibrosis, without cirrhosis.

Clinical pearls

• Cardiovascular disease is the leading cause of death in MASLD.

• Limit alcohol: it adds liver injury.

Key studies and references

1. Rinella ME, et al. A multisociety Delphi consensus statement on new fatty liver disease nomenclature. Hepatology. 2023

2. Rinella ME, et al. AASLD Practice Guidance on the clinical assessment and management of NAFLD. Hepatology. 2023

3. Harrison SA, et al. A phase 3 trial of resmetirom in NASH with liver fibrosis (MAESTRO-NASH). N Engl J Med. 2024

Trusted resources

• American Liver Foundation

Educational content only, written and reviewed by Farhan Tahir, MD. It does not replace individual medical advice. For sudden chest pain, trouble breathing or stroke symptoms, call 911.

AT A GLANCE

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