Fatty liver affects one in three Australian adults, mostly unnoticed

About one in every three Australian adults has fatty liver disease, according to the Liver Foundation. Most of them have no reason to suspect it. The condition usually causes no symptoms at all, and a person can feel entirely well while fat accumulates in the organ over many years.

That mix of very common and very quiet explains why fatty liver is so often discovered by accident, on a blood test or a scan ordered for something else.

What the term means

A healthy liver holds a small amount of fat. Healthdirect describes fatty liver as the point where fat makes up more than 5% of the liver's weight. There are two main types. One is caused by heavy drinking. The other, which Healthdirect calls the most common type, is tied to metabolic health: body weight, blood sugar, blood fats and blood pressure. The two can occur together in the same person.

The naming is still settling. For years the metabolic type was called non-alcoholic fatty liver disease, or NAFLD. The Liver Foundation and Healthdirect now call it metabolic associated fatty liver disease (MAFLD), and the 2024 consensus statement for GPs from the Gastroenterological Society of Australia (GESA) uses MAFLD as well. Internationally a newer label, MASLD, swaps the word "fatty" for "steatotic". The GESA statement notes that this term was proposed out of concern that "fatty" may be stigmatising. On a referral or a report, all three names point to broadly the same condition.

Why it stays quiet

The Liver Foundation is blunt on this point: fatty liver disease usually has no symptoms at all. When there are any, they are vague. General tiredness and an ache in the upper right side of the abdomen are the two it mentions, and neither points clearly to the liver.

Clearer signs belong to advanced disease. Healthdirect lists yellowing of the skin and eyes, dark urine, a swollen abdomen, easy bruising, itchy skin, vomiting blood and black stools, and advises seeing a doctor if signs of more serious liver disease appear. The Liver Foundation describes fatty liver as a condition that worsens slowly over time, so these signs arrive late.

Who is more likely to have it

The Liver Foundation's list of risk factors starts with carrying excess weight, particularly around the waist. It goes on to insulin resistance or type 2 diabetes, high cholesterol and high blood pressure. A diet heavy in fatty foods, sugary drinks and highly processed food is on the list too, as is an inactive lifestyle.

The overlap with diabetes and weight is large. The GESA statement reports that pooled studies find the condition in 55 to 60% of people with type 2 diabetes and in 55 to 75% of people with obesity. The same document notes that risk rises as metabolic health worsens, including in people of normal body weight.

Age matters as well. The Crossroads study, published in the Journal of Gastroenterology and Hepatology in 2023, examined adults in four regional Victorian towns at two points about fifteen years apart. In 2016–18, 35.4% met the study's definition of fatty liver after adjusting for age and sex, up from 32.4% in 2001–03. Among people aged 60 to 79 the figure rose from 34.8% to 43.1%. The researchers used a score calculated from body measurements and blood results rather than scanning every participant, so these are estimates, and they come from one region.

How it is usually found

According to Healthdirect, many people do not know they have fatty liver until a routine test shows signs of a liver problem. Sometimes that test is a liver panel ordered as part of a general check. Sometimes, as the Liver Foundation notes in its advice for people newly diagnosed, it is an ultrasound done for a different matter altogether.

For some groups, less is left to chance. The GESA statement recommends that GPs assess adults who have type 2 diabetes, obesity, or two or more metabolic risk factors such as high blood pressure, abnormal blood fats or prediabetes. Its recommended first test for liver fat is an ultrasound, which it describes as widely available and relatively inexpensive, though less sensitive in people with obesity or with only a small amount of fat.

Blood tests have a limit. According to the GESA statement, standard liver function tests are not accurate for detecting advanced scarring and may give normal results even when cirrhosis is present. A normal panel does not settle the question on its own.

What the stages mean

Doctors describe fatty liver along a path, although most people never travel its full length.

• Fat alone. Extra fat is stored in liver cells. The medical word is steatosis.
• Inflammation. In some people the fat is accompanied by injury and inflammation, called steatohepatitis. On reports it may appear as MASH.
• Scarring. Long-running inflammation can leave scar tissue, known as fibrosis. It is graded from 0 (none) to 4.
• Cirrhosis. Stage 4 is the most severe scarring. It raises the risk of serious complications, including liver cancer.

Movement between stages is generally slow. The GESA statement cites a pooled analysis in which people starting with no or minimal scarring took an average of ten years to progress by one stage. Some move faster: 6 to 15% of that group reached advanced scarring or cirrhosis within five years. Two Australian studies quoted in the statement found advanced scarring in 3.3% of people with fatty liver in rural Victoria and in 3.9% at a Brisbane primary care clinic. The great majority, in other words, did not have it.

The statement treats the amount of scarring as a key guide to a person's outlook, so it asks GPs to estimate it. The first step is a score called FIB-4, calculated from age and three routine blood results. A low score is rechecked at least every three years. An in-between score leads to a second test such as elastography, a scan that gauges how stiff the liver is. A high score leads to a specialist referral.

A summary of the same guidance in the Medical Journal of Australia states that cardiovascular disease is the most common cause of death in people with this condition, accounting for about a quarter of deaths. This is why a GP following up a fatty liver will usually look at blood pressure, cholesterol, blood sugar and kidney function too.

When to raise it with a GP

No article can say whether a particular reader has fatty liver. People in the groups GESA singles out, meaning those with type 2 diabetes, obesity or several metabolic risk factors, can reasonably ask their GP whether their liver has been looked at. Anyone who notices yellowing skin or eyes, dark urine, abdominal swelling, vomiting blood or black stools should seek medical care promptly.

Sources

1. Liver Foundation, Fatty liver disease (reviewed June 2025).
2. Healthdirect Australia, Fatty liver (last reviewed March 2025).
3. Gastroenterological Society of Australia, Recommendations for the assessment of metabolic dysfunction-associated fatty liver disease (MAFLD) in primary care: a consensus statement (2024).
4. Vaz K and colleagues, Journal of Gastroenterology and Hepatology, Non-alcoholic fatty liver disease prevalence in Australia has risen over 15 years in conjunction with increased prevalence of obesity and reduction in healthy lifestyle (2023).
5. Liver Foundation, Your doctor says you have fatty liver disease. Now what? (2023).
6. Adams LA and colleagues, Medical Journal of Australia, Assessment of metabolic dysfunction-associated fatty liver disease in primary care: a consensus statement summary (2025).