Fatty Liver Disease: MASLD and MASH

The liver is the body's metabolic hub. When insulin signaling is impaired, the liver both takes in more fat and produces more of it. Over time that fat accumulates inside liver cells.

The current names, MASLD and MASH, formerly called NAFLD and NASH, sit under the umbrella term steatotic liver disease and reflect what the disease actually is: liver disease driven by metabolic dysfunction. MASLD describes fat in the liver. MASH adds inflammation and cell injury, which is what leads to scarring.

A separate category, MetALD, describes people who have metabolic risk factors and also drink meaningfully. Naming it separately matters, because two sources of injury are managed differently from one.

Fat alone is relatively quiet. Inflammation is the turning point. Injured liver cells trigger repair, and repeated repair lays down fibrous tissue. Enough fibrosis over enough years becomes cirrhosis.

The progression is slow and silent, and it is not inevitable. Fibrosis stage is the single strongest predictor of long term outcome.

Liver enzymes start the conversation but do not settle it. Enzymes can be normal even with significant disease. Other causes are ruled out first, including viral hepatitis, alcohol related injury, medication effects, and autoimmune disease.

FIB-4, a score calculated from routine bloodwork, is the first line screen. Vibration controlled transient elastography, often called FibroScan, refines the risk estimate by measuring liver stiffness. Biopsy is reserved for cases that remain unclear. Hepatology manages this pathway.

Treatment aims at the metabolic driver. Improving insulin sensitivity reduces liver fat. Reducing liver fat reduces inflammation. Reducing inflammation slows or stops fibrosis.

Nutrition change, alcohol reduction, treatment of diabetes and lipids, and medication where indicated all contribute.

The first medication for MASH with moderate to advanced fibrosis received accelerated FDA approval in 2024, used alongside diet and exercise. It is prescribed and monitored by hepatology, and it does not replace treating the underlying metabolic driver.

Metabolic surgery improves hepatic steatosis and can improve MASH and the degree of fibrosis, which is why liver status is part of the surgical conversation rather than a separate file. Hepatology and surgery frequently plan together in advanced cases.

A surgical opinion is reasonable when fatty liver disease coexists with type 2 diabetes or other metabolic conditions, when fibrosis staging shows progression, or when medical management has not moved the picture. Liver status also affects operative planning, so it is assessed before any procedure.

This page is educational information, not medical advice. What is right for you is decided in consultation, after a review of your history, your symptoms, and your testing.