By Annie Kay 

 Medically reviewed by Robert Burakoff, MD

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.

There are two types of fatty liver: metabolic dysfunction-associated steatotic liver disease (MASLD, formerly known nonalcoholic fatty liver disease or NAFLD) and alcoholic fatty liver disease (AFLD). MASLD is usually preventable and is linked to obesity, type 2 diabetes, and diet. It affects 25 to 30% of people living in the United States and Europe.1 AFLD is linked with drinking excessive amounts of alcohol.

Early-stage fatty liver disease can often be reversed with lifestyle changes. When damage to the liver continues beyond its capacity to repair itself, liver damage and health issues often result. If left untreated, fatty liver disease can progress to cirrhosis, which can lead to liver failure and may require a liver transplant.

magicmine / Getty Images

In June 2023, the American Association for the Study of Liver Diseases, along with several other liver research societies and patient advocacy groups, announced new names for the conditions NAFLD and NASH. The names were changed to more accurately reflect the causes of the conditions and to reduce the usage of stigmatizing language.2

What Is the Liver?

The liver is a large reddish-brown digestive organ that sits on the right side of your abdomen. It plays critical roles in digestion and maintaining overall health.

Among the jobs of the liver:

• The liver produces bile, which helps break down fat so it can be absorbed in the digestive tract.

• Biotransformation of toxic substances from normal metabolism, medications, and alcohol in the liver prepares them for removal from your body.

• The liver produces proteins.

• It makes and recycles a wide variety of essential biochemicals.

The liver commonly repairs itself when its cells become damaged.

Fatty Liver Disease Symptoms

In its early stages, fatty liver disease usually does not have symptoms.

As it progresses, fatty liver disease can cause:

• Loss of appetite

• Abdominal pain

• Nausea and vomiting

• Jaundice (a yellow tone to your skin)

Acute fatty liver of pregnancy is a rare but serious complication that can develop during the third trimester of pregnancy. Symptoms include nausea and vomiting, poor appetite, pain in the upper-right abdomen, headache, generally feeling sick, fatigue, and jaundice.

A pregnant person experiencing any of these symptoms must be evaluated and managed immediately. Most people recover completely post-delivery.

Causes

Risk factors for developing fatty liver disease include:

• Excessive use of alcohol (AFLD)

• Higher body weight or obesity

• Diabetes or pre-diabetes

• Diet high in sugar and processed foods

• Hyperlipidemia, especially with high triglycerides (a blood lipid)

• Low physical activity

• Digestive issues

• Genetic predisposition

Fatty liver can also develop with rapid weight loss or as a side effect of certain medications. Many of the risks of MASLD can be addressed with changes to lifestyle choices.

Diagnosis

Fatty liver disease is diagnosed through a medical exam, and various tests, including liver function and blood count tests, or imaging tests. Your healthcare provider will ask about your medical history including alcohol intake, and your weight and diet.

Fatty liver disease is diagnosed when more than 5% of the weight of the liver is fat.

Metabolic dysfunction-associated steatohepatitis (MASH, formerly known as nonalcoholic steatohepatitis or NASH) is a type of MASLD, and this occurs when more than 5% of the liver is fat and inflammation is also present.3 MASH is a serious condition that can progress to scarring, an increased risk for cancer, and liver failure if it's not treated.

Treatment

Changing your lifestyle choices, such as improving your diet and reducing alcohol intake, are the primary treatments for fatty liver disease.

MASLD

For MASLD, making lifestyle changes that include increasing your physical activity and improving your diet to include more fruits, vegetables, and whole grains will help reverse fatty liver.4

While certain nutritional supplements have shown promise in the treatment of fatty liver, more research is needed. Working with a qualified nutritionist can help you make effective changes and determine if a nutritional supplement might be helpful.

If medication may be causing your fatty liver disease, your healthcare provider will recommend how to replace that medication.

In 2024, the Food and Drug Administration (FDA) approved Rezdiffra (resmetirom) for the treatment of adults with MASH with moderate to advanced liver scarring (fibrosis). Rezdiffra is the first and only FDA-approved treatment for MASH. Rezdiffra works to decrease liver scarring and should be used along with diet and exercise. 

AFLD

The primary treatment for alcoholic fatty liver disease is to stop drinking alcohol. Therapists are available who can help, or you can participate in an alcohol recovery program. These programs sometimes use treatments with medicines that can reduce cravings for alcohol, or that make you feel ill if you drink alcohol.

Coping

As with many chronic lifestyle conditions, a diagnosis of fatty liver disease can cause you to blame yourself for your illness. You may wonder how serious your condition is and how long you have until your condition is life-threatening.

Speaking with a therapist can be helpful to process the difficult emotions that can come with a diagnosis like fatty liver disease. Work closely with your medical team to determine the best course of action for you and your individual case, as well as work with your therapist to handle the emotional aspect of your diagnosis.

Sources

National Institute of Diabetes and Digestive and Kidney Disease. What is NAFLD?

Rinella ME, Lazarus JV, Ratziu V, et al. A multi-society Delphi consensus statement on new fatty liver disease nomenclature. Ann Hepatol. 2023;101133. doi:10.1016/j.aohep.2023.101133

National Institute of Diabetes and Digestive and Kidney Disease. What Is NAFLD and NASH?

National Institute of Diabetes and Digestive and Kidney Disease. How Can My Diet Help Prevent or Treat NAFLD or NASH?

Additional Reading

US National Library of Medicine. Medline Plus. Fatty Liver Disease.

By Annie Kay
Annie B. Kay, MS, RDN, C-IAYT, is an integrative dietitian and yoga therapist.