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23rd May, 20218 min read

Nonalcoholic fatty liver disease (NAFLD)

Medical reviewer:Dr Ann Nainan
Author:Dr Lauretta Ihonor
Last reviewed: 12/04/2021
Medically reviewed

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What is nonalcoholic fatty liver disease?

Nonalcoholic fatty liver disease (NAFLD) is when you have too much fat in your liver.

But NAFLD doesn’t describe a single condition, instead it refers to a group of conditions that all feature an unusual build-up of fat in the liver.

This group of conditions are called ‘nonalcoholic’ because, while many types of liver disease can be caused by heavy drinking, NAFLD specifically affects people who don’t drink a lot of alcohol.

Fatty liver stages

NAFLD usually progresses in 4 stages.

Stage 1: Simple fatty liver (hepatic steatosis)

At this early stage, your liver – which usually has very little fat in it – develops a build-up of fat. This build-up is harmless in most cases and doesn’t cause symptoms or harm your liver. But it can sometimes progress to the next stage of NAFLD.

Stage 2: Nonalcoholic steatohepatitis (NASH)

At this stage, the build-up of fat in your liver is now accompanied by inflammation. Like stage 1, NASH usually doesn’t cause any symptoms.

Stage 3: Liver fibrosis

This is when ongoing inflammation causes scar tissue to develop in the liver. If you have fibrosis, your liver usually continues to work as normal – especially in the earlier stages.

Stage 4: Liver cirrhosis

At this late stage, most of the normal tissue in your liver has been replaced with scar tissue, and your liver shrinks and stops working properly. Once you have cirrhosis there isn’t anything you can do to reverse it. It can also progress to a more serious stage, known as liver failure – when your liver stops working properly – and this can shorten your life expectancy.

But it usually takes a long time (often years) for cirrhosis to develop and there are several things you can do to reduce your risk of progressing from early-stage NAFLD to cirrhosis.

NAFLD symptoms

Most people with NAFLD have no symptoms during the early stages. You may only find out you have it during a test for something else.

But as NAFLD progresses, you may notice symptoms like:

  • pain in the upper right side of your tummy – this pain is often described as a dull ache
  • losing weight without meaning to
  • feeling very tired
  • feeling weak

If you develop cirrhosis, you may notice new symptoms, including:

  • loss of appetite
  • dark coloured pee
  • itchy skin
  • swollen feet, ankles, legs (oedema) and tummy (ascites)
  • yellowing of your skin and the whites of your eyes

When to see a doctor about NAFLD

It's possible to stop NAFLD from progressing if it’s diagnosed and treated early, so see a doctor if you think you have any of the symptoms listed above or you think you may have NAFLD.

See a doctor or go to hospital immediately if you:

  • have tummy pain that feels very bad or suddenly gets worse
  • have tummy pain and a fever, diarrhoea or vomiting
  • are vomiting blood or something that looks like coffee grounds
  • notice your poo looks black or like tar
  • notice your tummy has swollen up
  • feel dizzy or confused
  • notice that your skin or the whites of your eyes have become yellow
  • haven’t peed in the past 24 hours, feel breathless, feel generally unwell or have any other signs of sepsis

Also, see a doctor if you’ve lost weight without meaning to.

What causes NAFLD?

It’s still not clear why some people develop NAFLD and others don’t. But it’s thought that certain factors can increase your risk of developing it. These include:

  • being overweight
  • having high levels of blood fats like cholesterol
  • having diabetes or high blood pressure
  • taking certain medications
  • being older than 50
  • being male
  • losing weight very quickly
  • smoking

But keep in mind that having these risk factors doesn’t mean you will develop NAFLD. And it’s also possible to have none of these risk factors and get NAFLD.

Read more about the causes of fatty liver disease.

How is NAFLD diagnosed?

Several tests can be used to help diagnose NAFLD. These include:

  • blood tests – known as liver function tests or LFTs. These tests measure your blood levels of certain substances made by your liver. If your levels aren’t within the normal range, this can suggest you have NAFLD
  • imaging scans – usually an ultrasound scan, but a CT or MRI scan may be done in some cases
  • liver biopsy – while liver biopsies aren’t routinely used if a doctor suspects NAFLD, it’s the only test that can definitely confirm if you have NAFLD. It involves taking a small sample of liver tissue and looking at it under a microscope for signs of NAFLD, like a build-up of fat, inflammation and scar tissue

Treatment of NAFLD

Because lifestyle factors tend to increase the risk of NAFLD progressing from an early stage to a late stage, treatment for NAFLD is mainly based on making lifestyle changes rather than on treating the liver disease itself.

Lifestyle changes a doctor may suggest include:

  • losing weight gradually – if you’re overweight or obese
  • not smoking
  • exercising regularly
  • eating a balanced, healthy diet – read more about the best diet for fatty liver disease, including which foods to avoid
  • not drinking alcohol – even though NAFLD isn’t caused by alcohol, drinking can make it worse

Speak to a doctor for advice on how to safely make these lifestyle changes.

In addition to making lifestyle changes, a doctor may also help you manage NAFLD by treating any conditions you have that can make NAFLD worse. Such conditions include high blood pressure, diabetes and high cholesterol.

They may also review any medications you’re taking that may be causing NAFLD or making it worse.

You’ll also need to be regularly monitored by a doctor – this may be a liver specialist, known as a hepatologist.

If NAFLD progresses to the later stages of cirrhosis or liver failure, and your liver stops working properly you may need a liver transplant. Speak to your hepatologist for more information about a transplant. They can help guide you through the process of making the decision to have (or not have) a transplant.

Can you prevent NAFLD?

Making lifestyle changes to remove or reduce the risk factors linked to NAFLD can help reduce your risk of developing it. But it’s important to remember that some people without known risk factors still develop NAFLD, so there’s no guarantee that these changes will prevent you from NAFLD.

What can I expect if I have NAFLD?

NAFLD is not a serious or life-threatening problem when it’s in the early stages. And most people with NAFLD don’t progress beyond the early stages (stages 1 and 2).

It can also be reversed if you lose weight (if you’re overweight) and control diabetes (if you have it).

But if NAFLD progresses to its later stages, it becomes more serious, not reversible and potentially life-threatening.

However, it’s important to remember that it usually takes many years to progress from early-stage NAFLD to cirrhosis. And this progression can often be avoided by making lifestyle changes, having regular checkups with a doctor and managing medical conditions like high blood pressure, high cholesterol and diabetes.

Your questions answered

How serious is fatty liver?

“Fatty liver disease can vary in how serious it gets. When it first develops, it tends to be a simple build-up of fat cells in your liver – this can usually be treated with lifestyle changes such as a healthy diet and regular exercise. But if the fat cells keep building up, it can progress to more serious types of liver disease, like cirrhosis, which may lead to liver failure. Although only a small percentage of people get cirrhosis, it's important to treat fatty liver early, so see a doctor if you think you have fatty liver." - Answered by Dr Rhianna McClymont, Lead Doctor at Livi. Click here to speak to a registered doctor by video, today (UK only).

Does fatty liver go away?

It’s possible to reverse fatty liver when it’s at an early stage. For some people, this can be done by making changes like losing excess weight.

And when fatty liver is caused by diabetes, making sure the condition is well controlled can also reverse fatty liver in its early stages.

Can fatty liver cause back pain?

Fatty liver doesn’t usually cause back pain or other symptoms in its early stages, although some people report a dull ache in the top right area of their tummy or vague tummy discomfort. Back pain also isn’t commonly reported as a symptom in the later stages of fatty liver, so speak to a doctor if you have unexplained back pain.

Key takeaways

  • nonalcoholic fatty liver disease (NAFLD) is when you have too much fat in your liver
  • it refers to a group of conditions that all feature an unusual build-up of fat in the liver
  • there are 4 stages of NAFLD: simple fatty liver, nonalcoholic steatohepatitis (NASH), fibrosis and cirrhosis
  • most people with NAFLD don’t progress beyond stage 2 (NASH)
  • treatment for NAFLD typically involves making lifestyle changes, like not smoking and losing weight (if you’re overweight), and managing conditions like high blood pressure and diabetes
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