Quick answer
What is fatty liver disease?
Fatty liver disease means excess fat stored in liver cells — usually linked to obesity, type 2 diabetes, and metabolic syndrome rather than alcohol. Most people have no symptoms — found on blood tests or scans. Weight loss of 5 to 10% is the main treatment. A small proportion progresses to inflammation (NASH) and cirrhosis. See a GP if liver blood tests are abnormal — exclude alcohol and other causes.
Fatty liver disease — NAFLD explained
Non-alcohol related fatty liver disease (NAFLD) — now often termed MASLD (metabolic dysfunction-associated steatotic liver disease) in updated nomenclature — is excess fat in liver cells not primarily caused by alcohol.
It affects an estimated 20 to 30% of UK adults — parallel to obesity and type 2 diabetes epidemics. Most people never know they have it until blood tests or ultrasound for other reasons.
Spectrum of disease
| Stage | Name | Risk |
|---|---|---|
| Simple steatosis | Fat only | Low — liver function often normal |
| NASH | Steatohepatitis — inflammation | Moderate — can scar |
| Fibrosis | Scarring | Progressive |
| Cirrhosis | End-stage scarring | Liver failure, cancer risk |
Not everyone progresses — majority remain stable with simple fat.
Causes and risk factors
- obesity — especially abdominal fat
- type 2 diabetes and prediabetes
- insulin resistance
- high cholesterol/triglycerides
- metabolic syndrome
- polycystic ovary syndrome
- ** obstructive sleep apnoea**
- rapid weight loss — paradoxically can worsen NASH transiently
- genetics — PNPLA3 variant common
Alcohol: any intake adds injury — honest alcohol history essential — dual pathology common.
Symptoms
Early: asymptomatic
Later (cirrhosis):
- fatigue
- right upper abdominal discomfort
- jaundice — yellow skin/eyes
- itchy skin
- ascites — fluid belly
- leg swelling
- easy bruising
- confusion — encephalopathy
Diagnosis
GP pathway:
- Abnormal LFTs — raised ALT/AST (ALT often higher)
- Exclude other causes:
- alcohol-related liver disease — AUDIT questionnaire
- hepatitis B and C
- autoimmune hepatitis
- haemochromatosis — ferritin, transferrin saturation
- coeliac disease — if indicated
- Ultrasound — bright liver, excludes focal lesions
- Fibrosis assessment — Fib-4 calculation, FibroScan in secondary care
Treatment — no magic pill (yet)
Weight loss — cornerstone
7 to 10% body weight loss:
- reduces liver fat
- improves NASH histology in trials
- see weight loss guide
Exercise
150 to 200 minutes weekly — improves enzymes independent of weight loss
Metabolic control
- HbA1c targets in diabetes
- statins — safe in NAFLD — reduce CV risk
- blood pressure control
Medicines
- vitamin E — selected non-diabetic NASH — specialist
- pioglitazone — insulin sensitiser — specialist
- GLP-1 agonists — emerging evidence for liver fat reduction in obesity/diabetes
- no universal NHS pill for all NAFLD yet
Alcohol
** abstinence or minimal** — even moderate alcohol accelerates harm in fatty liver
Monitoring
Regular LFTs — track trend
Fibrosis reassessment if risk factors persist
Screen for cardiovascular disease — main cause of death in NAFLD patients
When to worry
Urgent referral:
- jaundice
- ascites
- variceal bleed
- platelets falling, albumin low — synthetic function failing
Fatty liver is reversible early — weight and metabolic health are treatment; ignoring abnormal LFTs risks preventable cirrhosis.
Common questions
- What causes a fatty liver?
- Excess calories stored as fat in liver cells — strongly linked to obesity, insulin resistance, type 2 diabetes, high cholesterol, and metabolic syndrome. Less commonly rapid weight loss, certain medicines, or genetic factors. Alcohol-related fatty liver is separate diagnosis — alcohol intake must be assessed honestly.
- Can fatty liver be reversed?
- Yes — weight loss of 5 to 10% body weight reduces liver fat and inflammation in most people. Exercise improves liver enzymes even without major weight loss. Controlling diabetes and cholesterol helps. Simple fatty liver often fully reverses; scarring (fibrosis) may be partially reversible early.
- What are the symptoms of fatty liver disease?
- Usually none — discovered on routine blood tests (raised ALT) or ultrasound. Advanced disease — tiredness, discomfort upper right abdomen, jaundice, itchy skin, swollen legs or abdomen — signs of cirrhosis. Most never reach this stage with lifestyle intervention.
- Is fatty liver dangerous?
- Simple steatosis is low short-term risk. NASH with inflammation and fibrosis can progress to cirrhosis, liver failure, and liver cancer over years — similar pathways to alcohol cirrhosis. Cardiovascular disease risk is also elevated — manage heart risk factors.
- What should I eat for fatty liver?
- Mediterranean-style diet — vegetables, whole grains, olive oil, fish; limit sugary drinks, refined carbs, and processed food. No specific miracle food — calorie deficit if overweight matters most. Coffee may have modest protective association in studies — not a treatment alone.
- Do I need a liver biopsy?
- Not routinely — non-invasive scores (Fib-4, ELF test, FibroScan) estimate fibrosis in many cases. Biopsy reserved for uncertain diagnosis or research — specialist decision.