Understanding Metabolic Fatty Liver Disease

Fatty liver disease happens when too much fat builds up in the liver. While many people associate liver disease with alcohol use, one of the most common forms is linked instead to metabolic health.

It is called metabolic dysfunction-associated steatotic liver disease, or MASLD. You may recognize its former name, nonalcoholic fatty liver disease, or NAFLD.

MASLD develops when excess fat builds up in the liver in someone who also has one or more metabolic risk factors. In many people, the condition remains stable for years. In others, it can lead to inflammation, liver damage and eventually scarring.

One of the biggest challenges is that MASLD can develop quietly, often without noticeable symptoms.

Who Is at Risk for MASLD?

While MASLD is closely tied to metabolic health, there is no single profile of someone who develops it.

Risk is higher in people with conditions such as:

• Type 2 diabetes
• Insulin resistance
• High blood pressure
• High triglycerides or abnormal cholesterol levels
• Overweight or obesity

However, you do not need to have all of these risk factors to develop MASLD.

Also, body weight does not tell the whole story. MASLD can occur in people who are not living with obesity. Genetics, where the body tends to store fat, insulin sensitivity and other metabolic factors can influence risk.

This is one reason MASLD can be easy to overlook. Someone may feel well and may not fit the picture they associate with liver disease, yet still have excess fat accumulating in the liver.

What Happens When MASLD Progresses?

Having MASLD does not mean you will develop serious liver disease. For many people, fat may remain in the liver without causing significant damage.

In some people, however, the liver becomes inflamed and injured. When this happens, the condition is called metabolic dysfunction-associated steatohepatitis, or MASH. You may recognize its former name, nonalcoholic steatohepatitis, or NASH.

The difference between the two is important. With MASLD, excess fat is present in the liver. With MASH, that fat buildup is accompanied by inflammation and liver injury. Over time, ongoing inflammation can cause fibrosis, which is the medical term for scarring.

The possible progression looks like this:

MASLD → MASH → fibrosis → cirrhosis

This progression is not inevitable. Not everyone with MASLD develops MASH, and not everyone with MASH develops cirrhosis.

The goal is to identify people who may be developing significant liver scarring so steps can be taken to protect the liver from further damage.

What Is Cirrhosis?

The liver has an impressive ability to recover from many types of injury. However, repeated or ongoing damage can gradually replace healthy liver tissue with scar tissue.

When scarring becomes extensive and permanently changes the liver's structure, it is called cirrhosis.

Cirrhosis can make it harder for the liver to perform its many essential jobs, including processing nutrients, removing waste products from the blood, making proteins needed for blood clotting and helping regulate metabolism.

Advanced cirrhosis can lead to complications such as fluid buildup in the abdomen, internal bleeding, confusion, liver failure and an increased risk of liver cancer.

This is why identifying liver disease before severe scarring develops can be important.

Would You Know If You Had MASLD?

Possibly not.

Many people with MASLD have few or no symptoms, particularly in the earlier stages. Someone can feel generally well even while fat or inflammation is present in the liver.

When symptoms do occur, they can be vague. Some people may experience fatigue or discomfort in the upper right side of the abdomen.

Even cirrhosis may not cause obvious symptoms at first. As liver function worsens, symptoms can include:

• Unexplained fatigue or weakness
• Loss of appetite
• Unintended weight loss
• Itchy skin
• Easy bruising or bleeding
• Swelling in the legs or abdomen
• Yellowing of the skin or whites of the eyes
• Confusion or difficulty thinking

These symptoms can have many causes and do not automatically mean someone has liver disease. However, they should be discussed with a healthcare provider.

Why Does Type 2 Diabetes Matter?

Type 2 diabetes and MASLD are closely connected because they often share the same underlying problem—insulin resistance.

Insulin helps move glucose from the blood into the body’s cells. When the body becomes resistant to insulin, it has a harder time using that glucose effectively. Insulin resistance also can change how the body handles fat, making it easier for excess fat to build up in the liver.

That is one reason MASLD is more common in people with type 2 diabetes. Many people with diabetes also have other metabolic risk factors, such as high blood pressure, abnormal cholesterol levels or excess weight, which can further increase the risk of fatty liver disease.

Because MASLD often causes no symptoms, a healthcare provider may consider liver health when caring for someone with type 2 diabetes even if there are no obvious signs of liver disease.

Would Routine Blood Work Find MASLD?

Not always.

Blood tests that measure liver enzymes, including ALT and AST, can provide clues that the liver may be under stress, but they do not tell the whole story.

A person can have MASLD or liver fibrosis without dramatically abnormal liver enzyme levels. At the same time, abnormal liver enzymes can have many causes other than MASLD.

If liver disease is a concern, healthcare providers may use information from routine blood tests to calculate a score such as FIB-4. This can help estimate the likelihood of advanced liver fibrosis.

Imaging also may be used. An ultrasound, CT scan or MRI can sometimes identify fat in the liver. Tests called elastography can measure liver stiffness, which can help assess whether significant scarring may be present.

In some situations, a liver biopsy may be recommended to determine the type and severity of liver damage, although many people can be evaluated without one.

Can MASLD Improve?

In many cases, yes.

Liver fat and earlier stages of liver damage may improve, particularly when the metabolic conditions contributing to MASLD are addressed. Lifestyle changes remain an important part of treatment. For people whoare overweight or have obesity, gradual weight loss may help reduce liver fat and inflammation. However, weight is not the only factor that matters.

Physical activity can benefit liver and metabolic health even when it does not result in significant weight loss. Regular movement also can improve insulin sensitivity and support cardiovascular health.

Nutrition matters as well. A healthcare provider or registered dietitian may recommend an eating pattern that emphasizes vegetables, fruits, whole grains, legumes, healthy fats and other nutrient-dense foods while limiting added sugars, saturated fats and heavily refined foods.

One thing you do not need is a liver “detox.” Your liver already performs the body's detoxification work.

Be cautious about supplements or products marketed as liver cleanses. Some herbal and dietary supplements can actually harm the liver. Talk with your healthcare provider before taking supplements marketed for liver health.

Are Medications Available for MASH?

Treatment options for MASH have expanded in recent years.

For some adults with MASH and moderate-to-advanced liver fibrosis who have not developed cirrhosis, FDA-approved medications are now available.

Resmetirom, sold under the brand name Rezdiffra, was the first medication approved specifically for certain adults with MASH/NASH and moderate-to-advanced fibrosis.

Semaglutide, sold under the brand name Wegovy, also is FDA-approved to treat certain adults with MASH and moderate-to-advanced fibrosis.

These medications are not appropriate for everyone with MASLD or MASH, and they do not replace management of diabetes, high blood pressure, abnormal cholesterol, excess weight or other metabolic conditions that may be contributing to liver disease.

Treatment depends on factors including the amount of liver scarring present, other health conditions and a person's overall health.

For people who have already developed cirrhosis, treatment is different. Healthcare providers focus on treating the underlying cause when possible, slowing additional liver damage and monitoring for complications.

What Can You Do to Protect Your Liver?

You do not need a complicated liver-health routine. Many of the same habits that support your heart and metabolic health also support your liver:

• Stay physically active.
• Work toward a healthy weight if recommended by your healthcare provider.
• Manage diabetes, cholesterol and blood pressure.
• Eat a balanced diet and limit foods high in added sugars and heavily refined carbohydrates.
• Follow your healthcare provider's recommendations about alcohol, particularly if you have liver disease.
• Review medications and supplements with your healthcare provider.
• Keep recommended healthcare visits and laboratory testing.

It is also important to understand your individual risk.

If you have type 2 diabetes, obesity, abnormal cholesterol levels, high blood pressure or other metabolic risk factors, ask your healthcare provider whether your liver health should be evaluated.

The Bottom Line

MASLD is more than fat in the liver. It is closely connected to metabolic health and often develops without obvious symptoms.

Having MASLD does not mean serious liver disease is inevitable. Many people never progress to advanced disease, and lifestyle changes, management of metabolic conditions and newer treatment options may help protect liver health.

Knowing your risk is an important first step. If you have diabetes, obesity, abnormal cholesterol, high blood pressure or other metabolic risk factors, talk with your healthcare provider about whether MASLD should be on your radar.