For decades, fatty liver disease lived in the shadow of more recognizable conditions like diabetes and heart disease. Today, it is one of the most common chronic illnesses worldwide and has been quietly renamed. In 2023, an international expert panel replaced the term “nonalcoholic fatty liver disease” (NAFLD) with metabolic dysfunction–associated steatotic liver disease, or MASLD. The change signals a shift in how clinicians think about the condition: less about what it is not (alcohol), more about what is actually driving it (metabolic dysfunction).
Roughly 25 to 30 percent of adults globally have some form of MASLD, according to estimates summarized by the National Institute of Diabetes and Digestive and Kidney Diseases. Most people have no idea, because early-stage fatty liver typically produces no symptoms at all.
What MASLD Actually Is
MASLD describes a buildup of fat in liver cells in people who consume little or no alcohol, in the presence of at least one metabolic risk factor — such as obesity, type 2 diabetes, high blood pressure, or abnormal lipid levels. The disease exists on a spectrum:
- Simple steatosis: Excess fat in liver cells, but no significant inflammation or damage.
- MASH (metabolic dysfunction–associated steatohepatitis): Fat buildup plus inflammation and liver cell injury. Previously called NASH.
- Fibrosis: Persistent inflammation triggers scar tissue formation.
- Cirrhosis: Advanced scarring that can lead to liver failure or liver cancer.
Not every person with MASLD progresses through these stages. Research published in the journal Hepatology suggests that roughly 20 to 25 percent of MASLD patients develop the more aggressive MASH form, and a smaller subset develop significant fibrosis over years or decades.
Why It Often Goes Undetected
Most people with early MASLD feel fine. When symptoms appear, they are vague: fatigue, mild discomfort in the upper-right abdomen, or general malaise. The disease is often discovered accidentally — an ultrasound for unrelated reasons, or routine bloodwork showing elevated liver enzymes such as ALT and AST.
Because traditional liver function tests can be normal even in advanced disease, the American Association for the Study of Liver Diseases recommends that adults with type 2 diabetes, obesity, or two or more metabolic risk factors be screened using noninvasive tools such as the FIB-4 score and, when indicated, transient elastography (FibroScan), which estimates liver stiffness as a proxy for scarring.
What Drives MASLD
The core driver is insulin resistance, the same metabolic disturbance underlying type 2 diabetes. When the body’s cells stop responding efficiently to insulin, the liver receives signals to take in more glucose and produce more fat. Other contributors include:
- Excess calories, especially from refined carbohydrates and added sugars
- High intake of fructose, particularly from sugary drinks
- Sedentary behavior
- Genetic variants such as PNPLA3 and TM6SF2 polymorphisms
- Disrupted gut microbiome composition
- Sleep disorders, including obstructive sleep apnea
Diet and Lifestyle: The Foundation of Reversal
For most patients, early-stage MASLD is reversible — and lifestyle change remains the most powerful intervention. A landmark study published in Gastroenterology found that adults with MASH who achieved 7 to 10 percent body weight loss saw substantial reductions in liver fat, inflammation, and even fibrosis. Smaller losses around 5 percent reduced fat but rarely reversed scarring.
The Mediterranean Pattern
The European Association for the Study of the Liver and the American College of Gastroenterology both highlight the Mediterranean diet as the most evidence-supported eating pattern for MASLD. It emphasizes vegetables, fruit, legumes, whole grains, fish, nuts, and extra-virgin olive oil while limiting processed meats, refined carbohydrates, and added sugars. Multiple randomized trials show this pattern reduces liver fat independently of weight loss.
Cutting Liquid Sugar
Research suggests sugar-sweetened beverages may have an outsized effect on liver fat, partly because fructose is metabolized almost exclusively in the liver. Studies indicate that reducing or eliminating sugary drinks can lower liver fat content within weeks, even without significant overall weight loss.
Movement Matters
Exercise improves MASLD even when scale weight does not change much. A meta-analysis in the Journal of Hepatology found that both aerobic exercise and resistance training reduce liver fat, with combinations of the two showing the strongest effects. Most guidelines recommend at least 150 minutes per week of moderate-intensity activity, plus two days of strength training.
Coffee’s Surprising Role
Several large observational studies, including analyses in BMC Public Health, suggest that regular coffee consumption is associated with lower risk of MASLD progression and reduced liver fibrosis. The mechanism is not fully understood but may involve polyphenols and effects on hepatic enzymes. Coffee is not a treatment, but it is one of the few beverages with consistently favorable associations.
The New Drug Era: Rezdiffra
For years, no medication was approved specifically for MASLD or MASH. That changed in March 2024, when the U.S. Food and Drug Administration approved resmetirom (brand name Rezdiffra) for adults with noncirrhotic MASH and moderate to advanced liver fibrosis. Resmetirom is a thyroid hormone receptor–beta agonist that acts on the liver to reduce fat accumulation and inflammation.
The pivotal MAESTRO-NASH trial, published in the New England Journal of Medicine, showed that after one year of treatment, roughly a quarter to a third of patients on resmetirom achieved MASH resolution or fibrosis improvement, compared with about 10 to 15 percent on placebo. The drug is taken once daily as a pill and is generally well-tolerated, though side effects can include diarrhea, nausea, and itching, particularly in the first weeks.
Resmetirom is not a substitute for lifestyle treatment — it is meant to be added on top of it — and access remains limited by insurance coverage and the requirement for specialist evaluation. Several additional MASH drugs, including GLP-1 receptor agonists and FGF21 analogs, are in late-stage trials and may broaden options over the next few years.
What to Discuss With Your Doctor
Anyone with persistent obesity, type 2 diabetes, or unexplained elevations in liver enzymes can ask whether MASLD screening is appropriate. For people already diagnosed, the conversation often focuses on cardiovascular risk, because heart disease — not liver failure — is the leading cause of death in MASLD. Cholesterol management, blood pressure control, and glucose control all influence liver outcomes as well as overall longevity.
The Bottom Line
MASLD is common, often silent, and increasingly recognized as a whole-body metabolic problem rather than just a liver issue. The most effective tools remain dietary patterns built around whole foods, regular movement, weight reduction when appropriate, and treatment of associated conditions. New medications expand options for those with more advanced disease, but they work best alongside, not instead of, the foundational changes that make liver tissue healthier.
Disclosure: This content is for informational purposes only and is not medical advice. Always consult a qualified healthcare provider before making changes to your health regimen.