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Fatty liver disease — now formally called metabolic dysfunction-associated steatotic liver disease (MASLD), and historically known as nonalcoholic fatty liver disease (NAFLD) — is a condition in which excess fat builds up in the liver of someone who drinks little or no alcohol, driven by metabolic problems like excess weight, type 2 diabetes, high blood pressure, and abnormal cholesterol. In most people it is silent and stable, but in a meaningful minority the fat triggers inflammation and scarring (fibrosis) that can slowly progress over years toward cirrhosis — which is why it is now diagnosed, staged, and, increasingly, treated.
Fatty liver disease describes the accumulation of fat (steatosis) in liver cells in a person who is not a heavy drinker. When more than roughly 5% of the liver's weight is fat, the liver is considered "steatotic."
The terminology changed in 2023. A consensus of international liver societies, including the American Association for the Study of Liver Diseases (AASLD), replaced "nonalcoholic fatty liver disease (NAFLD)" with metabolic dysfunction-associated steatotic liver disease (MASLD), and renamed the more aggressive form "nonalcoholic steatohepatitis (NASH)" as metabolic dysfunction-associated steatohepatitis (MASH) (AASLD, 2023). The umbrella term steatotic liver disease (SLD) now covers all causes of liver fat. The relabeling was intended to remove stigmatizing words ("fatty," "nonalcoholic") and to define the disease by what actually drives it — metabolic dysfunction — rather than by what it is not. You will still see NAFLD and NASH used widely, and the two naming systems describe essentially the same patients.
It helps to think of fatty liver as a spectrum rather than a single disease:
The single most important thing to understand is that the amount of liver fat matters far less than the amount of fibrosis. Fibrosis stage is the strongest predictor of long-term liver-related outcomes, which is why modern care focuses on finding and stopping scarring early.
The relevant ICD-10 codes include K76.0 (fatty change of liver, not elsewhere classified) and K75.81 (nonalcoholic steatohepatitis/NASH).
MASLD is fundamentally a manifestation of metabolic dysfunction — the same cluster of problems that drives heart disease and type 2 diabetes. Under the current definition, MASLD requires liver fat plus at least one cardiometabolic risk factor (AASLD, 2023). Key risk factors include:
The mechanism is rooted in insulin resistance. When the body's cells stop responding normally to insulin, the liver is flooded with fatty acids and sugar and converts the excess into fat that is stored in liver cells. In a subset of people, that stored fat triggers oxidative stress and inflammation, which over time recruits scar-forming cells and produces fibrosis.
Certain groups carry higher risk: people with type 2 diabetes (in whom MASLD prevalence is very high — well over half), people with obesity, those of Hispanic ethnicity, people with polycystic ovary syndrome (PCOS) or obstructive sleep apnea, and people with a particular genetic variant in the PNPLA3 gene, which raises both the risk of fat accumulation and of progression to fibrosis. Risk also rises with age. Importantly, MASLD can occur in people who are not overweight ("lean MASLD"), typically still in the setting of insulin resistance.
MASLD is now estimated to affect roughly a third of adults globally, making it the most common chronic liver condition worldwide. Among people with type 2 diabetes, prevalence is far higher still.
A note on alcohol: by definition, MASLD applies to people who drink little or no alcohol. The 2023 nomenclature also created a new in-between category, MetALD, for people who have metabolic risk factors *and* drink moderate amounts of alcohol, recognizing that the two causes often overlap.
For most people, the honest answer is none. MASLD is usually silent and is frequently discovered by accident — through mildly elevated liver enzymes on a routine blood test, or fat seen on an ultrasound or CT done for another reason.
When symptoms do occur, they tend to be vague and nonspecific:
As the disease advances toward cirrhosis, more serious signs can emerge and warrant prompt medical attention:
Because symptoms appear so late, the absence of symptoms does not mean the liver is healthy. This is exactly why screening of high-risk groups — particularly people with type 2 diabetes or metabolic syndrome — has become a focus of recent guidance.
Diagnosis has two parts: confirming that there is excess liver fat, and — more importantly — estimating how much scarring (fibrosis) is present. Modern guidance emphasizes a stepwise, mostly non-invasive approach (AASLD; AGA; American Diabetes Association).
Blood tests. Liver enzymes (ALT and AST) may be mildly elevated, but they are often normal even in significant disease, so normal enzymes do not rule out MASLD. Clinicians also check for and exclude other liver diseases (viral hepatitis, autoimmune and metabolic conditions) and assess metabolic markers (glucose/HbA1c, lipids).
Imaging for fat. Abdominal ultrasound is the usual first test that detects liver fat, though it is less sensitive when fat content is low. CT and MRI can also show steatosis; MRI-PDFF is a precise research-grade measure of fat fraction.
Non-invasive fibrosis risk scoring — the key step. Because fibrosis drives prognosis, guidelines recommend a two-step strategy:
Liver biopsy remains the reference standard for distinguishing simple steatosis from MASH and for precisely staging fibrosis, but it is invasive and is now reserved for selected cases where the diagnosis is unclear or where it will change management.
There is a clear hierarchy: lifestyle change is the foundation for everyone, and medication is layered on for those with confirmed steatohepatitis and meaningful fibrosis.
Weight loss is the single most effective intervention, and the benefit is dose-dependent (AASLD; AGA):
Practical measures with the strongest support:
For people with obesity, bariatric (metabolic) surgery can produce large, durable weight loss and substantial improvement in MASH and fibrosis in appropriate candidates.
Evidence here is limited and should be discussed with a clinician. Vitamin E (a high-dose antioxidant) has shown improvement in liver inflammation in selected non-diabetic adults with biopsy-proven MASH and may be considered on a case-by-case basis (AASLD); it is not recommended routinely, and long-term high-dose use carries its own risks. Most "liver detox" or "liver support" supplements lack quality evidence and are not a substitute for proven measures.
Until recently there were no drugs approved specifically for fatty liver disease; that has changed:
Drug choice depends on fibrosis stage, diabetes status, weight, and other conditions, and should be individualized with a hepatologist or appropriate specialist.
Largely, yes — because its main drivers are modifiable. The same habits that prevent it also keep it from progressing:
Long-term management is a partnership: periodic re-checking of fibrosis risk (for example, repeating FIB-4 or elastography over time), ongoing control of metabolic conditions, and protecting overall cardiovascular health — because, notably, most people with MASLD are more likely to die of cardiovascular disease than of liver disease. Crucially, fibrosis is not necessarily permanent: with sustained weight loss and metabolic improvement, earlier-stage scarring can stabilize or regress.
Talk to a clinician for evaluation if you have metabolic risk factors (type 2 diabetes, obesity, high blood pressure, abnormal cholesterol) or if a routine test has shown elevated liver enzymes or fat on imaging — even without symptoms — so that fibrosis can be assessed.
Seek prompt medical care for any of the following, which can signal advanced liver disease:
For most people, the outlook is good — particularly for those with simple steatosis and no significant fibrosis, who often remain stable for years, especially when metabolic risk factors are well managed.
The prognosis is driven by fibrosis stage. People with MASH and advancing fibrosis are at higher risk of progressing to cirrhosis, and MASLD has become one of the leading causes of cirrhosis and a rising cause of liver transplantation and liver cancer (hepatocellular carcinoma). The encouraging counterpoint is that fibrosis can stabilize or even improve with weight loss, metabolic control, and — for the right patients — the newer approved medications.
The other half of the prognosis lies outside the liver: because MASLD reflects systemic metabolic dysfunction, cardiovascular disease is the most common cause of death in this population. That is why good MASLD care looks a lot like good heart-health care.
Can fatty liver disease be reversed? Early fatty liver (simple steatosis) is often reversible, and even some fibrosis can improve. The most reliable path is sustained weight loss of around 7–10% of body weight, a Mediterranean-style diet, regular exercise, avoiding alcohol, and tight control of diabetes and cholesterol. Cirrhosis (advanced scarring) is much harder to reverse, which is why finding and treating the disease earlier matters.
Is fatty liver disease serious if I have no symptoms? It can be. MASLD is usually silent, and symptoms often appear only at advanced stages. The key is not whether you feel sick but whether you have fibrosis — which is assessed with simple tools like the FIB-4 score and FibroScan. Many people with MASLD never develop serious liver problems, but a meaningful minority do, so a one-time fibrosis risk check is worthwhile if you have metabolic risk factors.
Do I have to give up alcohol completely? By definition MASLD occurs in people who drink little or no alcohol, and alcohol adds a separate injury to an already-stressed liver. Most clinicians advise minimizing or avoiding alcohol, and avoiding it entirely if there is significant fibrosis. If you drink and also have metabolic risk factors, your condition may be classified as MetALD, and reducing alcohol becomes even more important.
What's the difference between fatty liver, NAFLD, MASLD, NASH, and MASH? "Fatty liver" is the everyday term. NAFLD and MASLD are the old and new names for the same condition (excess liver fat from metabolic causes). NASH and MASH are the old and new names for the more serious form, where fat is accompanied by inflammation and cell injury that can scar the liver. The 2023 rename (NAFLD to MASLD, NASH to MASH) was made to use clearer, less stigmatizing language.
Is there a pill for fatty liver disease now? Yes, for a specific group. As of 2024–2025, the FDA has approved resmetirom (Rezdiffra) and semaglutide (Wegovy) for adults with MASH and moderate-to-advanced fibrosis (stages F2–F3), used together with diet and exercise. These are prescribed and monitored by a specialist; they are not for everyone with fatty liver, and lifestyle change remains the foundation of treatment for all.
*This page is for general education and is not medical advice. Talk to a qualified healthcare professional about diagnosis and treatment decisions specific to you.*
As of 2024, resmetirom (brand name Rezdiffra) is the first and only FDA-approved drug specifically for NASH/MASH, granted accelerated approval in March 2024 for use together with diet and exercise in adults with noncirrhotic disease who have moderate to advanced liver fibrosis (stages F2-F3); it is not approved for cirrhosis and works by selectively activating thyroid hormone receptor-beta. The most evidence-based first-line treatment for all stages remains gradual weight loss (3-5% of body weight reduces liver fat; 7-10% can reduce inflammation and fibrosis), a Mediterranean-style diet, regular physical activity, limiting alcohol, and controlling diabetes, blood pressure, and cholesterol. For people who also have type 2 diabetes or obesity, professional guidance supports certain GLP-1 receptor agonists such as semaglutide for their metabolic and cardiovascular benefits. There is no approved over-the-counter supplement that treats the disease; vitamin E and pioglitazone are sometimes used off-label in select non-diabetic patients only under specialist supervision. All medication and supplement decisions should be made with a qualified clinician. This information is educational and is not medical advice.
Yes, in its early stages fatty liver disease is often reversible, though there is no single cure. When the buildup is simple fat (steatosis) without significant scarring, sustained weight loss, dietary change, and exercise can clear liver fat and reverse inflammation; losing roughly 7-10% of body weight is associated with improvement in steatohepatitis (MASH), and about 10% or more with regression of fibrosis. Once advanced scarring (cirrhosis) develops it generally cannot be undone, which is why early diagnosis and management matter. Work with a clinician to confirm your disease stage and the right plan for you.
They describe the same spectrum of disease under old and new names. In 2023 expert societies renamed nonalcoholic fatty liver disease (NAFLD) to metabolic dysfunction-associated steatotic liver disease (MASLD), and renamed the more aggressive form NASH (nonalcoholic steatohepatitis) to MASH (metabolic dysfunction-associated steatohepatitis). MASLD means fat in the liver plus at least one cardiometabolic risk factor, while MASH adds liver-cell injury and inflammation that can progress to scarring. The new terms emphasize metabolic causes rather than simply ruling out alcohol.
MASLD is driven by metabolic dysfunction rather than alcohol, so it is closely tied to excess weight, insulin resistance, and type 2 diabetes. Diagnosis requires liver fat plus at least one of five cardiometabolic risk factors: overweight or increased waist circumference, elevated blood sugar or diabetes, high blood pressure, high triglycerides, or low HDL cholesterol. Diets high in added sugars and processed foods, physical inactivity, genetics, and older age also contribute. A clinician can help identify which factors apply to you.
Fatty liver disease usually causes no symptoms in its early stages and is often found by chance through blood tests or imaging done for another reason. As it advances, some people develop fatigue or a dull ache or discomfort in the upper right abdomen. More serious signs such as jaundice (yellow skin or eyes), abdominal swelling, and unexplained weight loss generally appear only with advanced liver damage like cirrhosis. Because it is often silent, see a clinician if you have risk factors such as diabetes or obesity.
It is typically diagnosed by confirming fat in the liver on imaging (commonly ultrasound) together with at least one cardiometabolic risk factor, after excluding heavy alcohol use and other liver diseases. To assess scarring without surgery, clinicians often start with the FIB-4 blood-based score and may add specialized ultrasound elastography such as FibroScan (vibration-controlled transient elastography). Liver biopsy remains the reference standard for staging inflammation and fibrosis but is used selectively because it is invasive. Your clinician will choose the appropriate tests based on your risk.
The foundation of treatment is lifestyle change: gradual weight loss, a healthier diet, regular physical activity, limiting alcohol, and managing diabetes, cholesterol, and blood pressure. In March 2024 the FDA approved resmetirom (Rezdiffra), the first medication specifically for noncirrhotic MASH with moderate to advanced fibrosis, used alongside diet and exercise. GLP-1-based medicines such as semaglutide have also shown benefit for MASH, and weight-loss (bariatric) surgery is an option for some people with obesity. Treatment should be individualized with a clinician based on your disease stage and other conditions.
Fatty liver disease is often mild but can be serious if it progresses unchecked. Simple fat buildup may advance to MASH, where inflammation gradually scars the liver and can lead to cirrhosis, liver failure, or liver cancer over years. MASLD is also strongly linked to a higher risk of heart and blood-vessel disease, which is a leading cause of death in people with the condition. Early evaluation and ongoing care help lower these risks, so discuss monitoring with your clinician.
It is generally best to minimize or avoid alcohol if you have fatty liver disease, because alcohol adds further strain to a liver that is already under metabolic stress and can accelerate damage. By definition, MASLD occurs with little or no alcohol intake; when someone with metabolic risk factors drinks more (roughly 20-30 grams per day or more), the condition is classified as MetALD, reflecting combined causes. There is no universally safe amount for an at-risk liver. Ask your clinician for guidance specific to your situation and liver health.
This page is for general information and is not medical advice. Always consult a qualified clinician about diagnosis and treatment. Individual results vary.