Fatty liver disease, also referred to as hepatic steatosis, is a condition of the liver characterized by the accumulation of excess triglycerides and other fats in the liver cells.

Your liver is the largest organ inside your body. Its functions include, besides others, digesting food, storing energy, and removing toxins from the body.

A healthy liver normally contains a small amount of fat. However, when the accumulation of fat reaches 5% to 10% of your liver’s weight, it becomes fatty liver. This makes the liver more vulnerable to injury and more difficult to function.

It is the most common type of liver disease seen in the world today. It affects up to 25% of the population in the United States and is expected to continue to affect more people in the future.

This is because hepatic steatosis is associated with other rising comorbidities that can contribute to the development of this disease. These include type 2 diabetes, obesity, metabolic syndrome, sleep apnea, hypertension, polycystic syndrome, and high cholesterol. Obesity and diabetes are the two most common risk factors for fatty liver disease.

Most people with this condition do not have any symptoms and this condition stays harmless. It is not serious as long as it doesn’t lead to liver inflammation or damage.

However, with the proper diet formulated for fatty liver and a disciplined lifestyle, you can prevent and even reverse an existing fatty liver.

Heavy alcohol drinking over time makes you more prone to getting it. In such cases, it is referred to as Alcoholic Fatty Liver Disease or Alcoholic Steatohepatitis.

However, you can get this liver condition disease even if you don’t drink alcohol. In such people who do drink very little or no alcohol, it is referred to as Nonalcoholic Fatty Liver Disease (NAFLD) or Nonalcoholic Steatohepatitis (NASH).

It usually causes no symptoms. If symptoms do occur, they include fatigue, weight loss, and abdominal discomfort or pain.

Treatment and management of fatty liver disease primarily involve reducing the risk factors such as obesity through diet and exercise, abstaining from alcohol, and keeping comorbidities such as diabetes and hypertension under control.

Generally, this is a benign condition, but in a minority of patients, it can progress to liver cirrhosis.

According to the Mayo Clinic, between 5% and 12% of people with Non-alcoholic Steatohepatitis (NASH) will progress to cirrhosis.

Originally, it was thought that it took decades for NAFLD to progress to cirrhosis. However, recent studies have shown that NAFLD can progress to cirrhosis within 2 years. 

Types of fatty liver disease

There are two main types:

  1. Nonalcoholic fatty liver disease (NAFLD) or Non-alcoholic Steatohepatitis (NASH)
  2. Alcoholic fatty liver disease also called alcoholic steatohepatitis

What is nonalcoholic fatty liver disease (NAFLD)?

By definition, NAFLD occurs in patients who have a history of little or no consumption of alcohol. It develops in people who do not drink alcohol. It is again of two types:

  • Simple fatty liver has fat but little or no inflammation and no liver cell damage.
  • In Non-alcoholic steatohepatitis (NASH), along with fat, there is inflammation and liver cell damage, which can cause fibrosis or scarring of the liver. NASH can lead to cirrhosis or liver cancer.

NAFLD is the most common chronic liver disorder in the United States. It affects about 25% to 30% of people in the United States and Europe.

Both types of this liver disorders are becoming more common. This is because obesity, type 2 diabetes, and high cholesterol rates are rising in the United States. And, these are the most common risk factors that make you prone to fatty liver.

What is alcoholic fatty liver disease?

When fatty liver develops in someone who consumes too much alcohol, it’s known as alcoholic fatty liver disease (AFLD). About 5% of the United States population has alcoholic fatty liver disease.

It occurs due to heavy consumption of alcohol. Your liver metabolizes most of the alcohol you drink with the help of enzymes, so it can be got rid of from your body.

This action of the liver can generate harmful substances, mainly acetaldehyde (a highly toxic substance and known carcinogen) and oxygen radicals. These substances damage the liver and cause it to get inflamed.

The more alcohol you consume, the more your liver is damaged. Over the years, if alcohol consumption is not controlled, alcoholic fatty liver disease can progress to permanent liver damage and liver cirrhosis. As long as it doesn’t lead to liver inflammation this liver condition is not serious.

Causes and risk factors

Why nonalcoholic fatty liver disease (NAFLD) develops is unknown. However, research shows that it is more common in people with the following conditions, which increase their risk:

  • Type 2 diabetes raises your risk of NAFLD and it is seen in at least half the patients of those with type 2 diabetes.
  • Obesity is associated with an increased risk of NAFLD, which affects 70% and 90% of obese diabetics.
  • Middle age and older. The risk of NAFLD was significantly higher among individuals aged 35–55 years.
  • Hispanic and non-Hispanic whites
  • High cholesterol and triglyceride levels in the blood. Although high LDL cholesterol is a risk factor, high triglycerides are the strongest predictor of NAFLD.
  • High blood pressure. Essential hypertension is strongly associated with the development of a fatty liver.
  • Long-term use of certain drugs, such as corticosteroids and some cancer drugs. Drug-induced steatohepatitis accounts for approximately 2% of all cases of non-alcoholic steatohepatitis. Other drugs that can cause fatty liver on long-term use include antidepressant and antipsychotic medications and, most commonly, tamoxifen.
  • Metabolic syndrome is a strong high-risk factor for developing this liver disease since each of its components is an independent risk factor by itself. This syndrome includes a cluster of conditions that include high blood pressure, high blood sugar, excess body fat around the waist, and abnormal lipid levels.
  • Rapid loss of weight can increase your risk of developing this liver condition and can worsen an existing one.
  • History of chronic hepatitis C infection leads to steatosis. This prevalence is seen in 55% of hepatitis C virus infections.
  • Exposure to certain toxins such as pesticides, and metals including arsenic, mercury, and lead are potentially associated with toxic fatty liver.
  • Eating excess calories can cause fat to build up in the liver especially when the liver does not break down fats as it normally should. However, consumption of calories through plant-based unsaturated fats does not cause fat to be deposited in the liver. Consumption of a similar amount of calories through saturated fats markedly increases fat deposits in the liver.
  • Malnutrition. Chronic deficiency of protein and certain vitamins like E, D, B3, and some other micronutrients can predispose to this liver disease.
  • Alcohol abuse. Alcoholic fatty liver disease develops in people who have been heavy drinkers for a long period. The risk increases in women heavy drinkers who are obese and have certain genetic mutations. Fatty liver due to chronic alcohol use occurs due to the production of toxic metabolites such as aldehydes during the metabolism of alcohol in the liver.


Both NAFLD and alcoholic fatty liver disease (AFLD) are silent diseases and usually present no symptoms. However, if they do, both AFLD and NAFLD diseases present similarly.

Symptoms, if present, include a feeling of being tired or discomfort in the upper right side of your abdomen.

Some individuals with NAFLD can develop nonalcoholic steatohepatitis (NASH), which is the further stage where there is associated inflammation of the liver parenchyma. Over the years, NASH can further lead to scarring of the liver parenchyma. This is called cirrhosis

Possible signs and symptoms of NASH and advanced scarring (cirrhosis) include:

  • Nausea, loss of appetite, or drastic weight loss
  • Extreme tiredness
  • Mental confusion
  • Abdominal swelling (ascites)
  • Enlarged blood vessels just beneath the skin’s surface
  • Enlarged spleen
  • Red palms
  • Yellowing of the skin and eyes (jaundice)
  • Swollen abdomen and legs
  • Weakness

Grades of fatty liver

Based on the changes that are observed on the ultrasound, the fatty liver is graded into three grades as follows:

  • Grade I is the mildest form showing only mild steatosis. Here, the fat accumulates on the outside of the organ and does not interfere with its function.
  • Grade II is a moderate form of steatosis with impaired echogenicity of the main portal vein wall. This grade requires medical intervention to prevent the progression of the disease.
  • Grade III is the severe form of fatty liver, with the appearance of symptoms. The posterior hepatic parenchyma loses its normal appearance. This grade requires aggressive treatment.

How fatty liver progresses in stages

Fatty liver can progress through four stages:

  • Stage 1 of Simple fatty liver.  There is a simple buildup of excess fat in the liver cells. This is a harmless condition but has the potential to progress.
  • Stage 2 of Steatohepatitis. Besides the presence of excess fat, there’s also inflammation in the liver.
  • Stage 3 of Fibrosis. Chronic inflammation in the liver has now caused scarring. In this stage, however, the liver can still function normally.
  • Stage 4 of liver cirrhosis. This is the last, most severe, and irreversible stage of fatty liver, in which scarring of the liver has become widespread, liver function is impaired, and death becomes inevitable.

You can reverse early fatty liver disease (stages one and two) by managing any risk factors you have such as losing weight, controlling any comorbidities you may have, abstaining from alcohol, and sticking to the right diet.