Many people overlook small changes in their bowel habits, but experts are warning that one specific sign could point to a serious liver condition.
While symptoms like blood in the stool, constipation, diarrhoea, stomach pain, and unexplained weight loss all require medical attention, there’s another indicator worth knowing about—especially if it appears suddenly or persists.
The warning concerns non-alcoholic fatty liver disease (NAFLD), also known as metabolic dysfunction-associated steatotic liver disease (MASLD). This condition develops when more than five per cent of the liver contains fat, even in people who drink little or no alcohol.
Understanding Non-Alcoholic Fatty Liver Disease
According to the NHS, NAFLD progresses through four stages. The earliest, called “simple fatty liver,” involves excess fat stored in the liver cells but no inflammation or damage.
If left untreated, however, it can advance to “metabolic dysfunction-associated steatohepatitis (MASH),” a more severe stage where inflammation begins damaging the liver. Over time, this can lead to cirrhosis (scarring), liver cancer, or even liver failure.
The British Liver Trust lists several risk factors for MASLD:
Being overweight or obese
A large waistline
Type 2 diabetes
Poor diet high in processed or fatty foods
Low physical activity
High cholesterol or blood lipids
High blood pressure
Conditions linked to insulin resistance, such as polycystic ovary syndrome (PCOS)
The Hidden Nature of the Disease
In its early stages, NAFLD often causes no symptoms, which makes it easy to miss. “There are often no specific signs, even in later stages. Many people remain symptom-free for years,” the British Liver Trust explains.
The disease affects up to one in five people in the UK, with rates rising alongside obesity levels. Although excess weight is a major risk factor, the condition can still occur in people of healthy weight.
The Warning Sign in the Toilet
One of the key signs to watch for is dark, black, tarry poo. While this can also be linked to stomach ulcers, bowel issues, or even oesophageal cancer, it may also signal liver cirrhosis caused by fatty liver disease. Cirrhosis prevents the liver from working properly and can result in life-threatening complications if untreated.
Other Symptoms to Watch For
Early symptoms of cirrhosis may include:
Fatigue and tiredness
Discomfort or pain in the upper right abdomen (where the liver is located)
Experts stress that anyone with the following symptoms should see a doctor immediately:
Yellowing of the eyes or skin (jaundice)
Easy bruising
Dark urine
Swelling in the abdomen
Vomiting blood
Black or tarry stool
Periods of confusion, forgetfulness, mood changes, or poor judgment
Itchy skin
Final Advice
Even though fatty liver disease may start silently, it can become serious over time. Paying attention to your bowel habits and recognizing unusual signs—like black, tarry stool—could lead to early diagnosis and prevent severe liver damage. If you experience any of these symptoms, don’t delay—book an appointment with your GP as soon as possible for proper evaluation and care.