Fatty liver

What it is

Fatty liver - now usually called MASLD, metabolic dysfunction-associated steatotic liver disease - is fat accumulation in liver cells beyond a threshold. It is extremely common, affecting roughly a quarter to a third of adults in many countries, and most people who have it do not know.

In a minority it progresses to inflammation, then fibrosis, then cirrhosis. That progression is why it matters. The encouraging part is that liver fat is unusually responsive: exercise reduces it measurably even in the absence of weight loss, which is not true of many things.

What it feels like

• Nothing at all in the great majority of cases
• Sometimes a vague fullness or discomfort under the right ribs
• Fatigue, though it is non-specific and easily attributed elsewhere
• Usually found incidentally on a scan or through mildly raised liver enzymes on a blood test
• Advanced disease can cause jaundice, swelling and confusion, but that is a late stage

What causes it

Most people have more than one of these at once, and they feed each other. Read the list looking for the two or three that sound like your week rather than for the one true answer — the ones that describe you are the ones worth acting on.

Chronic energy surplus

Consistently taking in more energy than is used means the liver packages the excess as triglyceride. It is the fundamental driver and it operates slowly and invisibly.

Insulin resistance

Insulin resistance drives fat delivery to the liver and simultaneously stops the liver switching off its own glucose production. Fatty liver and type 2 diabetes are two views of the same underlying process.

Visceral fat

Fat inside the abdomen drains directly into the portal vein and therefore straight to the liver. This is why waist size predicts liver fat so much better than total weight.

Fructose and sugary drinks

Fructose is metabolised primarily in the liver and, in excess, is converted to fat there. Sugar-sweetened drinks are the most concentrated dietary source and are consistently associated with liver fat.

Inactivity

Physical activity increases fat oxidation in the liver and muscle. Exercise reduces liver fat independently of weight change, which is one of the clearest demonstrations that activity matters in its own right.

Alcohol

Alcohol causes its own fatty liver disease and compounds the metabolic version. The distinction between the two is clinically useful and physiologically blurry - both damage the same organ.

Genetics

Variants such as PNPLA3 substantially affect how much liver fat accumulates for a given lifestyle, and they vary by ethnic background. This is why two people with the same habits can have very different livers.

Rapid weight loss

Very rapid loss can transiently worsen liver inflammation as fat is mobilised. It is an argument for a steady rate rather than against losing weight.

Polycystic ovary syndrome and other insulin-resistant states

Any condition driving insulin resistance drives liver fat with it. PCOS, sleep apnoea and untreated hypothyroidism all contribute.

Some medications

Tamoxifen, methotrexate, amiodarone and long-term steroids can all cause or worsen fatty liver. Worth reviewing when it appears without the usual drivers.

Who tends to get it

• Anyone with type 2 diabetes, in whom prevalence is very high
• People with central obesity or metabolic syndrome
• Anyone with raised liver enzymes on a routine test
• People with polycystic ovary syndrome or obstructive sleep apnoea
• Anyone of South Asian or Hispanic background, in whom genetic risk is higher

What makes it worse, and what settles it

The qFIT routine for this

Ready-made routineWeight, Cholesterol & Metabolic Health

qFIT already has this one built. It runs massage first, then stretching, then strength — the order that works on a body that is already sore — and every activity in it carries the reason it is there.

The button below opens your Checklist with this routine already selected, so instead of your whole list you land on just its Categories, Targets and Exercises, each with its checkbox, ready to tick as you work through them.

Have more than one problem? Tick yours under My Problems on My Profile and your Checklist's Routine list gains Recommended for my problems — every routine for the problems you picked, merged into one. Your picks stay private; that filter is the only thing they feed.

Get it checked if…

Jaundice, ascites or confusion needs urgent hepatology

And whatever the body part: chest pain or unusual breathlessness on exertion; a fever alongside the pain; unexplained weight loss; pain that is constant and unrelated to how you move; new numbness, weakness or loss of bladder or bowel control; or one calf that is swollen, warm and painful. Any of those, stop and get assessed.

How it usually goes

Liver fat responds fast: measurable reductions appear within four to twelve weeks of regular exercise, often before any weight change. Around five per cent weight loss reduces liver fat, seven per cent improves inflammation, and ten per cent can reverse some fibrosis. Most people never progress beyond simple fat accumulation, but progression is silent, so anyone with a diagnosis should stay under review rather than assume it is benign because it feels like nothing.

Prevalence basis: Meta-analysis of imaging-based prevalence studies

Others the same routine covers

These share the Weight, Cholesterol & Metabolic Health routine, so the work is the same. If one of them also sounds like you, that is a reason to expect more from it, not less.

This is general information, not a diagnosis, and it cannot examine you. If it matches you, use it to ask better questions of a clinician rather than to replace one.