Fatty liver is also known as hepatic steatosis. It happens when fat builds up in the liver. Having small amounts of fat in your liver is normal, but too much can become a health problem.

Your liver is the second-largest organ in your body. It helps process nutrients from food and drinks, and filters harmful substances from your blood.

Too much fat in your liver can cause liver inflammation, which can damage your liver and create scarring. In severe cases, this scarring can lead to liver failure.

When fatty liver develops in someone who drinks a lot of alcohol, it’s known as alcoholic fatty liver disease (AFLD).

In someone who doesn’t drink a lot of alcohol, it’s known as nonalcoholic fatty liver disease (NAFLD).

According to a 2017 research review, NAFLD affects up to 25 to 30 percent of people in the United States and Europe.

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Fatty liver can progress through four stages:

  1. Simple fatty liver. There’s a buildup of excess fat in the liver. Simple fatty liver is largely harmless if it doesn’t progress.
  2. Steatohepatitis. In addition to excess fat, there’s also inflammation in the liver.
  3. Fibrosis. Persistent inflammation in the liver has now caused scarring. However, the liver can still generally function normally.
  4. Cirrhosis. Scarring of the liver has become widespread, impairing the liver’s ability to function. This is the most severe stage and is irreversible.

Both AFLD and NAFLD present similarly. However, in many cases, fatty liver causes no noticeable symptoms. But you may feel tired, or experience discomfort or pain in the upper right side of your abdomen.

Some people with fatty liver disease develop complications, including liver scarring. Liver scarring is known as liver fibrosis. If you develop severe liver fibrosis, it’s known as cirrhosis, a potentially life threatening condition that can cause liver failure.

The liver damage due to cirrhosis is permanent. That’s why it’s so important to prevent it from developing in the first place.

Cirrhosis may cause symptoms such as:

To help stop fatty liver from progressing and causing complications, it’s important to follow your doctor’s recommended treatment plan.

There are two main types of fatty liver disease: nonalcoholic and alcoholic.

Fatty liver can also happen during pregnancy, although this is uncommon.

Nonalcoholic fatty liver disease (NAFLD)

Nonalcoholic fatty liver disease (NAFLD) is when fat builds up in the liver of people who don’t drink a lot of alcohol.

If you have excess fat in your liver and no history of heavy alcohol use, you may receive a diagnosis of NAFLD. If there’s no inflammation or other complications, the condition is known as simple NAFLD.

Nonalcoholic steatohepatitis (NASH) is a type of NAFLD. It’s when buildup of excess fat in the liver is accompanied by inflammation. Your doctor may diagnose NASH if:

  • you have excess fat in your liver
  • your liver is inflamed
  • you have no history of heavy alcohol use

When left untreated, NASH can cause liver fibrosis. In severe cases, this can progress to cirrhosis and liver failure.

Alcoholic fatty liver disease (AFLD)

Drinking a lot of alcohol damages the liver. Alcoholic fatty liver disease (AFLD) is the earliest stage of alcohol-related liver disease. If there’s no inflammation or other complications, the condition is known as simple alcoholic fatty liver.

Alcoholic steatohepatitis (ASH) is a type of AFLD. It’s when a buildup of excess fat in the liver is accompanied by inflammation, which is also known as alcoholic hepatitis. Your doctor may diagnose ASH if:

  • you have excess fat in your liver
  • your liver is inflamed
  • you drink a lot of alcohol

If it’s not treated properly, ASH can cause liver fibrosis. Severe liver scarring (cirrhosis) can lead to liver failure.

Acute fatty liver of pregnancy (AFLP)

Acute fatty liver of pregnancy (AFLP) is when excess fat builds up in the liver during pregnancy. It’s a rare but serious pregnancy complication. The exact cause is unknown, although genetics may be a reason.

When AFLP develops, it usually appears in the third trimester of pregnancy. If left untreated, it poses serious health risks to the mother and baby.

If your doctor diagnoses AFLP, they will want to deliver your baby as soon as possible. You might need to receive follow-up care for several days after you give birth.

Your liver health will likely return to normal within a few weeks of giving birth.

In fatty liver disease, excess fat is stored in liver cells, where it accumulates. A variety of factors can cause this fat buildup.

Drinking too much alcohol can cause AFLD. Heavy alcohol use can alter certain metabolic processes in the liver. Some of these metabolic products can combine with fatty acids, leading to the formation of types of fat that can accumulate in the liver.

In people who don’t drink a lot of alcohol, the cause of fatty liver disease is less clear. For these people, it’s possible their body produces too much fat or doesn’t metabolize fat efficiently enough.

One or more of the following factors may play a role in people who don’t consume much alcohol and develop fatty liver disease:

Other potential causes of fatty liver include:

  • pregnancy
  • side effects from some types of medications
  • some types of infections, such as hepatitis C
  • certain rare genetic conditions

The main risk factor for AFLD is drinking heavy amounts of alcohol. The Centers for Disease Control and Prevention (CDC) defines heavy drinking as:

  • 15 or more drinks per week for men
  • 8 or more drinks per week for women

Research has found that men who consume 40 to 80 grams of alcohol per day and women who consume 20 to 40 grams of alcohol per day over 10 to 12 years are at a higher risk of severe alcohol-related liver disease.

For reference, a standard drink contains about 14 grams of alcohol.

In addition to heavy alcohol consumption, other risk factors for AFLD include:

  • older age
  • genetics
  • obesity
  • smoking
  • a history of certain infections, such as hepatitis C

The major risk factors for NAFLD are:

Other risk factors for NAFLD include:

Remember that having risk factors means you’re at an increased risk of fatty liver disease compared with people who don’t have risk factors. It does not mean you’ll certainly develop it in the future.

If you have one or more risk factors for fatty liver disease, talk with your doctor about prevention strategies.

To diagnose fatty liver, your doctor will take your medical history, conduct a physical exam, and order one or more tests.

If your doctor suspects that you might have fatty liver, they will likely ask you questions about:

  • your family medical history, including any history of liver disease
  • your alcohol consumption and other lifestyle habits
  • any medical conditions you might have
  • any medications you might take
  • recent changes in your health

Let you doctor know if you’ve been experiencing fatigue, loss of appetite, or other unexplained symptoms.

Physical exam

To check for liver inflammation, your doctor may palpate or press on your abdomen. If your liver is enlarged, they might be able to feel it.

However, it’s possible for your liver to be inflamed without being enlarged. Your doctor might not be able to tell if your liver is inflamed by touch.

Blood tests

In many cases, fatty liver disease is diagnosed after blood tests show elevated liver enzymes. For example, your doctor may order the alanine aminotransferase test (ALT) and aspartate aminotransferase test (AST) to check your liver enzymes.

Your doctor might recommend these tests if you’ve developed signs or symptoms of liver disease, or they might be ordered as part of routine blood work.

Elevated liver enzymes are a sign of liver inflammation. Fatty liver disease is one potential cause of liver inflammation, but it’s not the only one.

If your test results are positive for elevated liver enzymes, your doctor will likely order additional tests to identify the cause of the inflammation.

Imaging studies

Your doctor may use one or more of the following imaging tests to check for excess fat or other problems with your liver:

They might also order a test known as vibration-controlled transient elastography (VCTE, FibroScan). This test uses low-frequency sound waves to measure liver stiffness. It can help check for scarring.

Liver biopsy

A liver biopsy is considered the best way to determine the severity of liver disease.

During a liver biopsy, a doctor will insert a needle into your liver and remove a piece of tissue for examination. They will give you a local anesthetic to lessen the pain.

This test can help determine whether you have fatty liver disease and liver scarring.

Currently, no medications have been approved to treat fatty liver disease. More research is needed to develop and test medications to treat this condition.

In many cases, lifestyle changes can help reverse most stages of fatty liver disease. For example, your doctor might advise you to:

  • limit or avoid alcohol
  • take steps to lose weight
  • make changes to your diet
  • avoid medications and supplements that are hard on your liver

If you have AFLD, your doctor will instruct you to completely abstain from alcohol. They may also recommend a detoxification program and counseling if you have alcohol use disorder (AUD).

Several viral infections can also damage the liver. To protect your liver health, your doctor may advise you to receive vaccines for hepatitis A and hepatitis B. Depending on your situation, they may also recommend regular screenings for hepatitis C.

Cirrhosis can also cause a variety of complications, including:

If you’ve developed complications from cirrhosis, your doctor might recommend additional treatments, such as medications or surgery.

Cirrhosis can also lead to liver failure. If you develop liver failure, you might need a liver transplant.

Lifestyle changes are the first-line treatment for fatty liver disease. Depending on your current condition and lifestyle habits, it might help to:

  • lose weight
  • reduce or abstain from alcohol consumption
  • eat a nutrient-rich diet that’s low in excess calories, saturated fat, and trans fats
  • get at least 30 minutes of exercise most days of the week

A 2020 research review suggests that vitamin E supplements might help improve ALT and AST levels, inflammation, and excess fat in NAFLD.

However, more research is needed. There are some health risks associated with consuming too much vitamin E.

Always talk with your doctor before you try a new supplement or natural remedy. Some supplements or natural remedies might put stress on your liver, or interact with medications you’re taking.

If you have fatty liver disease, your doctor might encourage you to adjust your diet to help treat the condition and lower your risk of complications.

For example, they might advise you to do the following:

  • Balance your diet. Try to select foods from all food groups. This includes fresh fruits and vegetables, whole grains, lean proteins, low fat dairy, and healthy fats and oils.
  • Cut calories. Aim to limit your consumption of foods that are high in calories.
  • Focus on fiber. Fiber can help improve the function of your liver. Example of foods that are rich in fiber include fresh fruits and vegetables, legumes, and whole grains.
  • Limit certain foods. Take steps to reduce your consumption of foods that are high in:
    • saturated fats, which are found in foods such red meat, full fat dairy, and fried foods
    • trans fats, which are present in fried foods and many processed snack foods
  • Avoid raw or undercooked shellfish. Raw or undercooked shellfish can contain bacteria that can make you seriously ill.
  • Address alcohol. Talk with your doctor about whether you can have alcohol. Depending on the condition of your liver, you may be able to drink alcohol in moderation. If you have AFLD, you’ll need to abstain from alcohol entirely.
  • Drink water. Drinking plenty of water can help keep you hydrated and also improve the health of your liver.

Learn more about some of the other dietary changes that may help you manage fatty liver disease.

To prevent fatty liver disease and its potential complications, it’s important to follow a healthy lifestyle. Some general prevention tips include:

  • limiting or avoiding alcohol
  • managing your weight
  • eating a nutrient-rich diet that’s low in saturated fats, trans fats, and refined carbohydrates
  • taking steps to manage your blood sugar, triglyceride levels, and cholesterol levels
  • following your doctor’s recommended treatment plan for diabetes, if you have this condition
  • aiming for at least 30 minutes of exercise most days of the week

Taking these steps can also help improve your overall health.

In many cases, it’s possible to reverse fatty liver disease through lifestyle changes, such as limiting alcohol, adjusting diet, and managing weight. These changes may help prevent further liver damage and scarring from occurring.

For AFLD in particular, it’s important to abstain from alcohol use entirely. If you need help with not drinking alcohol, consider engaging in a detoxification program and counseling.

When left untreated, fatty liver disease can progress to inflammation, fibrosis, and cirrhosis. Scarring due to cirrhosis isn’t reversible. If you develop cirrhosis, it also increases your risk of liver cancer and liver failure. These complications can be life threatening.

Generally speaking, the outlook for fatty liver disease is best when treatment begins in the early stages, before fibrosis and cirrhosis.

For the best outcome, it’s important to follow your doctor’s recommended treatment plan and practice an overall healthy lifestyle.

Fatty liver disease is when excess fat accumulates in the liver. This can happen due to heavy alcohol use. In this case, it’s known as alcoholic fatty liver disease (AFLD).

When fatty liver occurs in someone who doesn’t drink much alcohol, it’s known as nonalcoholic fatty liver disease (NAFLD).

Many people with fatty liver disease don’t experience significant symptoms until severe liver damage has occurred. When early symptoms are present, they can be nonspecific and include things like upper right abdominal pain and fatigue.

The primary treatment for fatty liver disease is to make lifestyle changes that promote liver health. It’s possible for the damage caused by fatty liver disease to be reversed when it’s treated in its early stages.