Fatty Liver Disease: Risk Factors, Symptoms, and How to Reverse It

The liver is busy. It performs more than 500 different functions, such as producing proteins and metabolizing medications. Because your liver has so many jobs, it’s important to keep it healthy. You might know that alcohol and certain infections (like hepatitis) can harm the liver, but you might not be aware that fat can damage it, too.

Fatty liver disease is exactly what it sounds like — fat buildup in the liver, causing problems.  The formal term for fatty liver disease is “nonalcoholic fatty-liver disease” (NAFLD). When the fat buildup also causes inflammation, it’s called “nonalcoholic steatohepatitis” (NASH). The “nonalcoholic” part just means that the condition wasn’t caused by drinking alcohol, which can also lead to fat buildup and inflammation in the liver. 

Fatty liver disease is very common. It affects over 25% of adults and anywhere from 7% to 34% of kids in the U.S. The good news? There’s a lot that can be done to prevent and even reverse the disease, if it’s caught early.  

What causes fatty liver disease?

Fatty liver disease is caused by a buildup of extra fat in the liver, but we aren’t exactly sure what causes that buildup. We know that having extra body fat increases the risk, and the way a person’s body processes sugars and fats might have something to do with it, too.

What risk factors are linked to fatty liver disease?

Certain genes also increase the chances of developing fatty liver disease. For instance, the condition is more common in Hispanic people than in other racial groups. 

Additional risk factors for fatty liver disease include: 

• A body mass index (BMI) greater than 25: Up to 75% of people who are overweight and more than 90% of people with obesity also have NAFLD.

• Larger waist size: Similar to BMI, increased waist circumference has been linked to NAFLD.  

• Type 2 diabetes: At least 50% of people with Type 2 diabetes have NAFLD.

• Metabolic syndrome: This condition is typically a combination of cholesterol problems, high blood pressure, increased waist size, and/or high blood sugars.

Do certain types of food contribute to fatty liver disease?

Sort of. No specific foods directly cause fat buildup in the liver, but making smart choices about what you eat and drink can help you to maintain a healthy weight and avoid metabolic syndrome. Exercise has also been shown to protect against fatty liver disease. So while this disease isn’t caused by any specific foods, lifestyle choices in general can contribute.

How are NAFLD and NASH different?

The difference is whether or not there’s inflammation in the liver. 

In NAFLD, there’s too much fat in the liver, but it’s not swollen or inflamed. In NASH, the extra fat causes swelling and inflammation. 

NASH is more severe, and more dangerous, because inflammation increases the risk of scarring in the liver. Both NAFLD and NASH can cause serious complications (see below), but the risk is higher with NASH. Fortunately, NASH is less common than NAFLD, affecting only 1.5% to 6.5% of people in the U.S.

What are the symptoms of fatty liver disease?

Most people with fatty liver disease don’t have any symptoms. 

Symptoms typically occur only in people who have severe or long-standing liver disease. 

When symptoms do occur, they can include:

• Yellowing of the skin or eyes (jaundice)

• Nausea and/or vomiting

• Fatigue and weakness

• Weight loss and loss of appetite

• Pain in the upper-right side of the abdomen

• Fluid buildup in the abdomen (ascites) or legs (edema)

• Itching

• Spider angiomas (dilated, spider-like blood vessels on the chest)

• Confusion

Note that many of these symptoms can be tied to a variety of conditions that affect the liver. They are not specific to fatty liver disease.

How is fatty liver disease diagnosed?

Since most people with fatty liver disease don’t have symptoms, it’s often discovered by accident, when tests are ordered for other reasons. For example, routine blood tests might show an elevation in the liver enzymes AST and ALT. In order to figure out why ALT and AST are elevated, your provider may order imaging tests (such as an ultrasound), which can reveal fat in the liver.  

Fat in the liver confirms the diagnosis of fatty liver disease. Next, it’s important to determine if the liver is just fatty (NAFLD), or fatty and inflamed (NASH). But that isn’t always a straightforward process. 

In many cases, the question can be answered by a liver biopsy — a procedure that involves removing a small piece of the liver with a needle and looking at it under a microscope. But liver biopsies are invasive, and not everyone needs one. Other tests may be more appropriate. Together with your provider, you can determine the best tests to get the answers you need.

What is the treatment for fatty liver disease?

Treatment for NAFLD involves diet changes and exercise. If changes are made early — before liver inflammation or scarring occur — fatty liver can be reversed. 

These steps can help reverse or prevent fatty liver disease:

• Losing weight

• Eating a healthy diet

• Exercising regularly

• Cutting back on alcohol

• Taking care of other health conditions, such as diabetes

Improvement depends on how advanced the liver disease is at diagnosis and whether you have other health problems. 

What are complications of fatty liver disease?

If left untreated, NAFLD and NASH can lead to serious complications, including liver failure (cirrhosis) and liver cancer. These risks are higher with NASH.

Why trust our experts?

Written by:

Samantha C. Shapiro, MD

Samantha Shapiro, MD, is a board-certified rheumatologist and internist with expertise in autoimmune and inflammatory conditions. She founded the division of rheumatology at Dell Medical School at The University of Texas at Austin.

Edited by:

Mandy Armitage, MD

Mandy Armitage, MD, has combined her interests in clinical medicine with her passion for education and content development for many years. She served as medical director for the health technology companies HealthLoop (now Get Well) and Doximity.

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