Liver disease is on the rise, in particular fatty liver disease, which is estimated to affect 20–30% of people in the UK, yet many people do not realise they have it until abnormal liver blood tests or an ultrasound scan of the abdomen reveal unexpected changes.

In this article, Dr Sarah Clark, Consultant in Gastroenterology, Hepatology and Hepatobiliary Medicine at New Victoria Hospital, explains what a fatty liver is, why liver blood tests matter, how the condition is investigated, and when specialist assessment may be recommended. Drawing on extensive experience diagnosing and managing liver disease, she also outlines how early intervention and lifestyle changes can help prevent progression and support better overall health.

What is fatty liver disease?

Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)

Fatty liver disease occurs when excess fat builds up inside liver cells. While a small amount of fat is normal, too much can interfere with liver function and, over time, may cause inflammation and damage.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the new name for non-alcoholic fatty liver disease (NAFLD), reflecting its close relationship with metabolic health and conditions such as obesity and diabetes.

One of the challenges with MASLD is that many people experience no symptoms whatsoever, even as the disease progresses. The condition can remain unnoticed for many years and is frequently discovered incidentally during routine health checks or scans performed for other reasons.

Alcoholic fatty liver disease (AFLD)

Alcoholic fatty liver disease (AFLD) is the initial, reversible stage of alcohol-related liver disease (ARLD). It is caused by heavy alcohol consumption, which leads to a buildup of fat in the liver. It rarely causes symptoms but acts as a critical warning sign that your drinking levels are harming your body. If heavy drinking continues, this reversible fat buildup can progress to severe, life-threatening conditions like alcoholic hepatitis and irreversible cirrhosis.

“A common misconception is that liver disease only affects people who drink heavily. In reality, metabolic factors such as body weight and blood sugar play a much bigger role. Metabolic dysfunction-associated steatotic liver disease is now the most common liver condition, but with early identification, there is a real opportunity to prevent progression.” Dr Sarah Clark, MBBS, MD, FRCP, Consultant Gastroenterologist and Hepatologist at New Victoria Hospital

Common causes and risk factors

Research shows that MASLD is closely linked with metabolic health and lifestyle factors.

Risk factors can include:

• Being overweight or obese, particularly carrying excess weight around the waist
• An unhealthy diet high in processed foods, sugar and carbonated beverages
• Lack of regular physical activity and sedentary lifestyle
• Active or passive smoking
• High blood pressure
• High cholesterol
• Type 2 diabetes and insulin resistance
• Increasing age
• Poor sleep quality

Alcohol intake also needs careful assessment because AFLD and MASLD can appear very similar, and some people may have elements of both.

Certain medical conditions can further increase the risk of developing fatty liver disease, including psoriasis, polycystic ovary syndrome (PCOS), thyroid disorders, diabetes and elevated serum uric acid levels.

Symptoms to watch for

Many people with fatty liver disease experience no symptoms at all. When symptoms do occur, they are often non-specific and may include:

• Persistent tiredness
• Reduced energy levels
• General feelings of being unwell
• Discomfort or a dull ache beneath the ribs on the right-hand side

Because these symptoms are common and can have many causes, they are often overlooked. However, persistent symptoms should always be discussed with a healthcare professional, particularly if risk factors for fatty liver disease are present, to prevent further health deterioration or complications.

How fatty liver is investigated

Assessment usually begins with a detailed discussion about symptoms, lifestyle and medical history.

Patients may undergo:

• Liver blood tests
• Additional blood tests to exclude viral hepatitis, autoimmune liver disease or other causes of abnormal liver function.
• An abdominal ultrasound to assess excess fat within the liver.
• Assessment of weight, waist circumference and body mass index.
• Review of alcohol intake and dietary habits.
• Evaluation of diabetes, cholesterol and blood pressure.

Where there is concern that liver scarring may be developing, specialists may recommend further investigations such as a FibroScan® or other fibrosis assessments like liver elastography to evaluate liver stiffness and determine whether significant scarring is present.

"The aim is not simply to diagnose fatty liver but to understand whether there is any inflammation or fibrosis developing, as this helps guide the most appropriate treatment and long-term monitoring." Dr Sarah Clark, MBBS, MD, FRCP

Liver blood tests

Liver blood tests measure enzymes and proteins produced by the liver, helping clinicians identify whether there may be inflammation or damage affecting the organ, help calculate fibrosis (scarring) risk, and ensure that other treatable causes of liver dysfunction are ruled out.

Common liver blood tests include:

• Alanine aminotransferase (ALT)
• Aspartate aminotransferase (AST)
• Gamma-glutamyl transferase (GGT)
• Alkaline phosphatase (ALP)
• Bilirubin
• Albumin

However, liver blood tests cannot diagnose fatty liver disease on their own. Some people with significant fatty liver have normal blood results, while others have mildly abnormal tests caused by other liver conditions. Instead, liver tests form one part of a wider assessment that also considers medical history, symptoms, physical examination and imaging studies where appropriate.

Fibrosis stages and the importance of early assessment

Fatty liver disease usually develops slowly and can progress through several stages. As inflammation persists, it can lead to fibrosis, which is the formation of scar tissue within the liver. Over time, this scarring may interfere with how well the liver functions and, if left untreated, can progress to more advanced liver disease.

• Stage 0 (simple steatosis): Fat builds up in the liver, but there is no inflammation or scarring. This stage is fully reversible.
• Stage 0–1 (MASH with little or no fibrosis): Known as metabolic dysfunction-associated steatohepatitis. There is mild inflammation and little or no scarring. Lifestyle changes can often reverse the condition.
• Stage 2 (moderate fibrosis): Some scarring has developed due to ongoing inflammation. The liver usually still works well, and some damage can be repaired.
• Stage 3 (advanced fibrosis): Significant scarring is present. Preventing further damage is essential, although some improvement is still possible.
• Stage 4 (cirrhosis): Extensive scarring changes the structure of the liver. It may still function, but severe scarring can lead to liver failure.

Many people remain in the early stages throughout their lives. However, in some cases, ongoing inflammation can lead to worsening scarring, cirrhosis, liver failure, or liver cancer.

Fatty liver disease is also linked to wider health risks. It is increasingly recognised as a marker of cardiovascular disease, meaning people with MASLD have a higher risk of heart problems.

The reassuring news is that progression is not inevitable. Having one stage does not mean someone will automatically develop the next. Adopting healthier eating habits, increasing physical activity and achieving weight loss where appropriate can slow progression or even reverse early liver damage. Early diagnosis offers the best opportunity to intervene before permanent liver damage develops.

How a specialist hepatology service can help

Receiving abnormal liver blood test results can feel uncertain, particularly when the cause is unclear. New Victoria Hospital's Hepatology Consultants offer expert assessment for patients with abnormal liver tests, suspected fatty liver disease and a wide range of liver conditions. Services include rapid access consultations, personalised investigations and tailored management plans designed around individual needs.

Where appropriate, care can be coordinated alongside the management of obesity, diabetes, high cholesterol and metabolic syndrome to provide a comprehensive approach to long-term health.

Treatment and management

Treatment focuses primarily on improving metabolic health and reducing fat within the liver.

Lifestyle measures remain the cornerstone of management and include:

• Following a balanced, Mediterranean-style diet, including moderate levels of coffee.
• Managing cholesterol and blood pressure
• Achieving sustainable weight loss if overweight
• Reducing alcohol consumption
• Increasing physical activity
• Stopping smoking
• Optimising diabetes control

Even modest weight loss can significantly reduce liver fat and improve inflammation.

Patients with more advanced fibrosis or cirrhosis may require specialist hepatology care and ongoing monitoring to reduce the risk of complications.

When to seek help

It is sensible to arrange specialist assessment if:

• Liver blood tests have been reported as abnormal
• Risk factors such as obesity, diabetes or high cholesterol are present
• A GP has suggested fatty liver disease may be present
• Persistent fatigue or upper abdominal discomfort continues without explanation
• There are concerns about long-term liver health

Timely investigation can provide reassurance where appropriate or identify opportunities for treatment before significant liver damage develops.

Key points

• Fatty liver disease is common and often causes no symptoms, even as the disease progresses.
• MASLD is the updated name for non-alcoholic fatty liver disease.
• Abnormal liver blood tests do not automatically indicate serious liver disease but should be properly assessed.
• Lifestyle changes can significantly improve liver health and reduce progression risk.
• Early diagnosis offers the best opportunity to prevent fibrosis and long-term complications.
• Specialist Hepatology assessment helps ensure the correct diagnosis and personalised management plan.

If you are concerned about your liver health

If you are concerned about your liver tests, risk factors or would like specialist review and advice, please book an appointment with our Hepatology Consultants: call 020 8949 9020 or fill out our online enquiry form.