What Is Fatty Liver Disease?

Fatty liver disease is a buildup of excess fat tissue in the liver. This can interfere with normal liver function and cause several health problems.

Globally, fatty liver disease is the most common chronic liver disease.¹

The two types of fatty liver disease are defined by their root cause:²

  • Alcoholic fatty liver disease (AFLD)

  • Metabolic-associated fatty liver disease (MAFLD), historically called non-alcoholic fatty liver disease (NAFLD)

As you can probably guess, AFLD is caused by excessive alcohol consumption over a long period of time.

By contrast, MAFLD is fatty liver disease without the involvement of alcohol. Instead, it’s caused by metabolism changes. Estimates indicate that roughly 20% of Americans experience MAFLD.³

The early stages of AFLD or MAFLD are generally asymptomatic.⁴ You likely won’t know you have fatty liver disease during this period.

Early detection and management can prevent the disease from progressing, often reversing it almost entirely.⁵ So it’s not all bad news.

Simple lifestyle changes, like healthy eating and exercising regularly, can help you avoid fatty liver disease.

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The early stages of fatty liver disease don’t often cause symptoms. The buildup of fat in the liver is not yet enough to affect normal liver functions.

Symptoms will appear and slowly worsen as the condition progresses over time.

Later stages of fatty liver disease can cause the following symptoms:⁶

  • Unexplained weight loss

  • Pain or discomfort in the upper right abdomen (where the liver is located)

  • Nausea and vomiting

  • Swelling in the area around the liver

  • Decreased appetite

  • Excessive fatigue or weakness

  • Excessive thirst

  • Abdominal bloating

Speaking to your doctor is advisable if you are experiencing any of these symptoms.

If left unaddressed, fatty liver disease can progress to cirrhosis, a condition where scar tissue forms throughout the liver.

Cirrhosis can cause the following symptoms:⁷

  • Abdominal swelling

  • Bruising or bleeding easily

  • Fluid retention in the legs, feet, and ankles

  • Yellowing of the skin and eyes (jaundice)

Is fatty liver disease fatal?

Fatty liver disease doesn’t cause problems for most people, but it can progress and become more serious if you don’t change your lifestyle and diet. Cirrhosis of the liver is a significant health risk.

Untreated cirrhosis of the liver can lead to liver failure. It also greatly increases your odds of developing liver cancer.⁸

You can’t live without a liver, so it’s wise to take care of the one you have. A liver transplant is the only option for restoring liver function if yours fails.

Stages of fatty liver disease and how it affects life expectancy

There are four stages of fatty liver disease. Each stage is associated with an increased risk of developing cardiovascular diseases and conditions like stroke and heart attack.⁹

Stage 1: simple fatty liver disease, or steatosis

The first stage of fatty liver disease is referred to as simple fatty liver or steatosis.

Steatosis is characterized by a buildup of fat in the liver. There is no inflammation or scarring at this point.

Many people with steatosis don’t know they have the condition or experience any symptoms. Most cases don’t progress beyond the first stage.¹⁰

You can reduce excess fat in your liver with dietary changes and regular exercise.

Stage 2: non-alcoholic steatohepatitis

The second stage of fatty liver disease is characterized by a further buildup of fat cells within the liver and inflammation.

Inflammation occurs in the liver in response to damage caused by fat tissue. As the amount of fat increases, so does the amount of damage. Scar tissue might develop if liver tissue is damaged faster than it can be repaired, leading to the third stage of fatty liver disease — fibrosis.

Stage 3: fibrosis

Scar tissue develops when inflammation in the liver causes damage more rapidly than the tissue can be healed.¹¹

This process has started to occur in people with stage three fatty liver disease. However, liver function is still largely preserved.

Removal or treatment of the cause of the damage (fat tissue) can help reduce inflammation, halting or reversing disease progression.

Without treatment, scar tissue will continue to develop. This leads to stage four fatty liver disease — cirrhosis.

Stage 4: cirrhosis

The fourth stage of fatty liver disease is called cirrhosis, where scar tissue replaces healthy, functioning liver tissue.

Cirrhosis severely impacts overall liver function. At this stage, you will experience significant liver disease symptoms.

Common signs of late-stage fatty liver disease include aching in the liver area (the upper right part of the abdomen), abdominal swelling, and yellowing of the eyes and skin (known as jaundice).¹²

Scar tissue in the liver is difficult to remove at this point, but you can prevent further disease progression through lifestyle changes.

Liver function is essential to life, so life expectancy is reduced at this point. Severe cases may require a liver transplant. 

Risk factors for developing fatty liver disease complications

Excessive and chronic alcohol consumption causes alcoholic fatty liver disease.

Several diseases and medical conditions can increase your risk of metabolic fatty liver disease, including:

  • High blood levels of cholesterol and triglycerides

  • Obesity, especially when excess fat is stored around the abdomen

  • Polycystic ovary syndrome (PCOS)

  • Type 2 diabetes

  • Underactive thyroid

  • Underactive pituitary gland

  • Sleep apnea

Fatty liver disease is also more common in older adults, people with any type of diabetes, and those with fat stored in the abdomen.

Can you treat or reverse the progression of fatty liver disease?

Halting the progression of fatty liver disease is possible in its early stages. It can also be reversed in some cases. This can be achieved through weight loss if you are overweight, managing diabetes, controlling high blood pressure, and reducing blood fats (triglycerides and cholesterol).

Regular exercise and a healthy diet may help you achieve these changes and stop the progression or even reverse fatty liver disease. Avoiding alcohol and tobacco are other measures to take.

Frequently asked questions

How fast does fatty liver disease progress?

Fatty liver disease is a progressive disease, meaning that it develops slowly, generally over multiple years.

The later stages of fatty liver disease, which involve scar tissue forming in the liver, take a considerable amount of time to develop.

Around 20% of people with scar tissue in the liver will develop stage four fatty liver disease (cirrhosis) within two years.¹³

What is the second stage of fatty liver disease?

The second stage of fatty liver disease is steatohepatitis. Inflammation in the liver occurs in this stage.

If left unchecked, the disease will progress and begin to cause more serious damage.

How long can you live with stage four fatty liver disease?

Stage four fatty liver disease involves cirrhosis, where scar tissue replaces healthy liver tissue. Cirrhosis is irreversible. It can significantly impact your life expectancy.

How long does it take for fatty liver to progress to cirrhosis?

Fatty liver disease progresses slowly. Studies indicate it may take upwards of ten years for alcohol-related fatty liver disease to progress to cirrhosis.¹⁴ This process may not cause symptoms until the later stages.

A healthy lifestyle can significantly reduce your risk of fatty liver disease.

Does fatty liver always cause cirrhosis?

No, fatty liver disease does not always progress to cirrhosis.

You can stop or reverse fatty liver disease, depending on the stage, through a combination of a healthy diet, proper management of health conditions like diabetes, and regular exercise.

Does fatty liver disease shorten your lifespan?

Yes, fatty liver disease will lower your life expectancy. Your specific situation and disease progression will affect how much your life expectancy is reduced. This also depends on the choices you make upon learning you have fatty liver disease.

A 2004 study found that early stages of fatty liver disease do not reduce life expectancy.¹⁵ However, it does increase your risk of other medical conditions like stroke and heart attack.

The lowdown

Fatty liver disease is a fairly common condition. It is often asymptomatic in the early stages.

You can manage fatty liver disease through a combination of regular exercise, a healthy diet, and proper management of medical conditions like diabetes and high blood pressure. Reducing or eliminating alcohol consumption is also important.

Taking the right steps to discourage fatty liver disease can reduce the effect it has on your life expectancy.

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