MASLD vs NAFLD: What Changed, Why It Matters, and What To Do

MASLD vs NAFLD: What Changed and Why It Matters

In 2023, the global hepatology community — led by a multi-society Delphi consensus (EASL, AASLD, ALEH, APASL) — formally replaced the term NAFLD (Non-Alcoholic Fatty Liver Disease) with MASLD (Metabolic-Associated Steatotic Liver Disease). This is not just a name change. It reflects a fundamental rethinking of how fatty liver disease is classified, communicated, and studied.

If you were told you have NAFLD, you almost certainly have MASLD. Here is what changed and what it means for your care.

Why Was the Name Changed?

• NAFLD was a diagnosis of exclusion — defined by the absence of alcohol use, without specifying what caused the fatty liver. This was scientifically imprecise and clinically unhelpful.
• Stigma — “non-alcoholic” inadvertently implied a link to alcohol even when the patient had never drunk. Patient groups highlighted this causes shame and barriers to disclosure.
• MASLD is positive and aetiological — it defines fatty liver by its actual drivers: metabolic risk factors (overweight/obesity, type 2 diabetes, hypertension, dyslipidaemia, or insulin resistance). This aligns diagnosis with causation.
• Better sub-classification — the new nomenclature creates a full taxonomy (see below), which allows clinical trials and registries to compare like-for-like populations.

The New Nomenclature: Full Taxonomy

New Term	Old Term	Definition
MASLD	NAFLD	Steatosis + ≥1 cardiometabolic risk factor, <20g/day alcohol (women), <30g/day (men)
MASH	NASH	MASLD with steatohepatitis (inflammation + ballooning on biopsy)
MetALD	Alcoholic + metabolic overlap	Steatosis + metabolic risk factors + moderate alcohol (20–50g/day women, 30–60g/day men)
ALD	Alcoholic Liver Disease	Steatosis due to heavy alcohol use (>50g/day women, >60g/day men)
Cryptogenic SLD	Cryptogenic NAFLD	Steatosis without metabolic risk factors or clear aetiology

What Does This Mean for Patients?

• If you were diagnosed with NAFLD — you now have MASLD (assuming you have at least one metabolic risk factor, which is true for the vast majority). Your disease, your risk, and your treatment are unchanged by the renaming.
• If you were diagnosed with NASH — you now have MASH. Same disease, new name. The treatment target — reversing inflammation and fibrosis — is identical.
• New drug approvals use MASLD/MASH terminology — resmetirom (Rezdiffra), the first FDA-approved drug for MASH with fibrosis, uses the new nomenclature. When reading about new treatments, MASH = NASH.
• Research articles from before 2023 still use NAFLD/NASH — do not be confused. The science is continuous; only the labels changed.

How Is MASLD Staged?

• S0–S3 — steatosis grade (S0: none, S3: severe, >67% of hepatocytes)
• F0–F4 — fibrosis stage (F0: none, F4: cirrhosis). Fibrosis stage is the most important predictor of long-term outcomes.
• Activity grade — NAS (NAFLD Activity Score) or SAF score; assesses steatosis, ballooning, lobular inflammation

What Is the Treatment for MASLD / MASH?

Treatment is determined by fibrosis stage, not the name of the disease:

• F0–F1 (no or mild fibrosis): lifestyle modification — Mediterranean diet, 150–200 min/week aerobic exercise, 7–10% body weight loss. No approved pharmacotherapy; weight loss is the most effective intervention.
• F2–F3 (significant fibrosis): lifestyle + consider pharmacotherapy. Resmetirom (thyroid hormone receptor-beta agonist) is FDA-approved in the US for MASH with F2–F3 fibrosis. Semaglutide (GLP-1 RA) reduces liver fat and shows signals of fibrosis improvement in phase 3 trials. Not yet approved specifically for MASH in India but increasingly used off-label.
• F4 (cirrhosis): treat complications (ascites, varices, hepatic encephalopathy), screen for hepatocellular carcinoma every 6 months, refer for liver transplant evaluation if decompensated.

Frequently Asked Questions

Is MASLD the same as NAFLD?

Yes, for most patients. MASLD replaced NAFLD in 2023 following an international multi-society consensus. Approximately 99% of patients previously diagnosed with NAFLD meet the criteria for MASLD. The underlying disease, its natural history, and its management are unchanged. Only the name and classification system have been updated.

What is the difference between MASLD and MASH?

MASLD is the umbrella term for fatty liver with metabolic risk factors. MASH (Metabolic-Associated Steatohepatitis, formerly NASH) is an advanced form of MASLD characterised by liver cell inflammation and ballooning injury in addition to fat. MASH carries a higher risk of fibrosis progression, cirrhosis, and liver cancer than simple MASLD.

Where can I see a fatty liver specialist in Mumbai?

Dr. Chetan Kalal — Associate Director, Hepatology & Liver Transplant, Gleneagles Hospital Mumbai — specialises in MASLD/MASH. He offers FibroScan, full metabolic assessment, and treatment planning aligned with 2024 EASL and APASL guidelines. Book an appointment here.