What is fatty liver and why does it develop?

Fatty liver occurs when excess fat accumulates in the liver. The condition often develops when the body stores more fat than it burns, although factors such as genetics, insulin resistance and other metabolic diseases also play an important role. Fatty liver is particularly common in people living with overweight, obesity, type 2 diabetes and metabolic syndrome.

The liver plays a central role in the body's metabolism. It helps regulate blood sugar, store energy and break down nutrients. When too much fat is stored in the liver, its normal function can become impaired and, in some people, this may eventually lead to inflammation and liver damage.

Today, the term MASLD (Metabolic dysfunction-associated steatotic liver disease) is commonly used for the most common type of fatty liver. The diagnosis refers to fatty liver associated with metabolic risk factors such as insulin resistance, overweight, elevated blood lipids and high blood pressure.

In some people, fatty liver progresses to MASH (Metabolic dysfunction-associated steatohepatitis). MASH means that fat accumulation in the liver has also led to inflammation and liver damage. Over time, the condition can cause scarring of the liver (fibrosis) and, in some cases, progress to liver cirrhosis. This is why it is important to identify and treat fatty liver at an early stage.

Why is fatty liver often diagnosed late in men?

Fatty liver rarely causes obvious symptoms in its early stages and is therefore often discovered only during routine blood tests or other medical examinations. Many people with fatty liver feel completely well, even though fat has already started to accumulate in the liver.

When symptoms do occur, they are often non-specific and can be difficult to link directly to the liver. Some people experience fatigue, low energy levels or a vague discomfort beneath the right side of the rib cage, where the liver is located.

Common symptoms and signs of fatty liver include:

• Fatigue or reduced energy levels
• A vague discomfort or feeling of pressure beneath the right side of the rib cage
• Elevated liver enzymes found on blood tests

Elevated liver enzymes may suggest fatty liver, but normal liver enzyme levels do not rule out the condition. As a result, fatty liver is often detected incidentally during routine health checks or imaging tests such as an ultrasound scan.

In men, fatty liver is often associated with abdominal obesity, insulin resistance, high blood pressure and other metabolic risk factors. Because fat accumulates around the internal organs, the liver can be affected for many years without causing obvious symptoms.

In some people, fatty liver may progress over time to inflammation and liver damage, a condition now known as MASH (Metabolic dysfunction-associated steatohepatitis). This is why it is important to identify and treat fatty liver early, particularly in people living with overweight, obesity or other metabolic risk factors.

When fatty liver increases the risk of type 2 diabetes, cardiovascular disease and other metabolic conditions

Fatty liver is closely linked to several metabolic diseases and is now considered part of a broader spectrum of metabolic dysfunction. The condition often occurs alongside insulin resistance, high blood pressure, elevated blood lipids and obesity.

The relationship is bidirectional. Insulin resistance can contribute to fat accumulating in the liver, while fatty liver can further impair the body's ability to regulate blood sugar and fat metabolism. As a result, fatty liver commonly occurs together with other metabolic risk factors.

People with fatty liver have a higher risk of developing type 2 diabetes and cardiovascular disease compared with people who do not have fatty liver. This risk is also influenced by factors such as the degree of insulin resistance, the amount of abdominal fat, blood pressure and blood lipid levels.

Because fatty liver rarely occurs in isolation, it is important not only to focus on the liver itself, but also to identify and treat other metabolic risk factors. Weight loss and healthier lifestyle habits can help improve both liver health and overall metabolic health.

Weight loss treatment for fatty liver

The main treatment for fatty liver is to reduce the amount of fat in the liver through weight loss and healthier lifestyle habits. For men living with overweight or obesity, even modest weight loss can lead to significant improvements in both liver health and overall metabolic health.

Research shows that losing around 7-10% of body weight can often reduce liver fat and improve liver enzyme levels. Greater weight loss may also improve inflammation and early signs of liver damage.

Three key components of treatment are nutrition, physical activity and, where appropriate, medication.

1. Weight loss and healthy eating habits

There is no specific "fatty liver diet", but a balanced diet based on nutrient-rich foods can support weight loss and help reduce fat accumulation in the liver.

• Choose plenty of vegetables, pulses, whole grains and other high-fibre foods.
• Include protein-rich foods such as fish, eggs, pulses and lean meat to help keep you feeling full.
• Limit sugar-sweetened drinks, large amounts of added sugar and ultra-processed foods.
• Include healthy fats from foods such as olive oil, nuts and oily fish.

2. Regular physical activity

A combination of everyday movement, aerobic exercise and strength training can improve both liver health and cardiometabolic health.

Regular physical activity can improve insulin sensitivity, reduce liver fat and support better metabolic health, even if weight loss is modest. Current recommendations advise at least 150 minutes of moderate-intensity physical activity each week, together with muscle-strengthening activities on at least two days a week. Exercise should always be tailored to each person's health, fitness level and daily circumstances.

3. Treating underlying risk factors

Fatty liver often occurs alongside insulin resistance, type 2 diabetes, high blood pressure and elevated blood lipids. It is therefore important to treat these conditions as well to reduce the strain on the liver and improve long-term health.

For people living with obesity, weight loss medication may be used alongside lifestyle changes. Studies have shown that modern obesity medications can have positive effects on both liver fat and other metabolic risk factors. The most appropriate treatment should always be determined through an individual medical assessment.

Frequently asked questions about fatty liver (FAQ)

What do the abbreviations MASLD and MASH stand for?

MASLD stands for Metabolic dysfunction-associated steatotic liver disease and is the current name for the most common form of fatty liver. The diagnosis is used when fat has accumulated in the liver in people with metabolic risk factors such as overweight, obesity, insulin resistance and high blood pressure. Previously, the condition was commonly referred to as NAFLD (Non-Alcoholic Fatty Liver Disease).

MASH stands for Metabolic dysfunction-associated steatohepatitis and is a more advanced stage of MASLD. In MASH, fat accumulation in the liver is accompanied by inflammation and liver damage. Over time, this may lead to scarring of the liver (fibrosis) and an increased risk of more advanced liver disease.

Not everyone with MASLD develops MASH, but MASH is considered a more serious stage of the condition and often requires closer medical follow-up.

What symptoms and early signs can fatty liver cause?

Fatty liver often causes no obvious symptoms in its early stages and is therefore frequently discovered by chance during blood tests or imaging investigations such as an ultrasound scan. Some people experience fatigue or discomfort beneath the right side of the rib cage, but these symptoms are often non-specific.

If fatty liver progresses to MASH, inflammation and liver damage can develop. Over the long term, this may lead to scarring of the liver, impaired liver function or liver cirrhosis in some people.

Diagnosis is based on an overall medical assessment, including blood tests, risk factors and, in some cases, imaging investigations such as ultrasound or elastography.

Is alcohol the cause of my fatty liver?

Not necessarily. Today, the most common form of fatty liver is associated with metabolic risk factors such as overweight, obesity, insulin resistance and type 2 diabetes, rather than excessive alcohol consumption. This form is now known as MASLD (Metabolic dysfunction-associated steatotic liver disease).

Alcohol can also cause fatty liver and other liver diseases, but many people with fatty liver drink little or no alcohol. It is therefore important to identify the underlying risk factors in each individual case.

If you are living with overweight, abdominal obesity, insulin resistance or type 2 diabetes, these factors are likely to contribute to fat accumulation in the liver. Alcohol use and metabolic risk factors can also occur together and affect the liver at the same time.

Yazen: sustainable weight loss

At Yazen, medical weight loss treatment is combined with lifestyle support from doctors and other healthcare professionals. The aim is to achieve sustainable, long-term weight loss that can improve both liver health and other metabolic risk factors, including type 2 diabetes, high blood pressure and cardiovascular disease.