Fatty liver disease

Fatty liver means that fat has accumulated inside liver cells. The liver is a working organ rather than a storage organ, and when more energy arrives than it can process or export, the surplus is parked inside the cells themselves.

The name has been changing, which causes some confusion when old and new reports sit in the same folder. What was called non-alcoholic fatty liver disease, or NAFLD, was renamed in 2023 to metabolic dysfunction-associated steatotic liver disease — MASLD — with its inflamed form, previously NASH, becoming MASH. The renaming did more than tidy the vocabulary. The old label defined the condition by what it was not, and required alcohol to be absent; the new one defines it by what it is, requiring fat in the liver alongside at least one cardiometabolic feature such as raised waist circumference, abnormal glucose, raised blood pressure or an abnormal lipid profile. It also created a category, MetALD, for the many people who have both metabolic risk and a meaningful alcohol intake, who previously had to be pushed into one box or the other.

It is the most common liver finding in India. Pooled estimates cluster around a third of adults, with urban figures higher, and it is being reported in people in their twenties and thirties far more often than a decade ago. India became one of the first countries to fold it into its national non-communicable disease programme, which is a reasonable indication of the scale involved. Most people affected feel entirely well.

The reason it matters is not the fat itself. Fat sitting quietly in the liver does very little. The concern is the sequence that can follow. In a proportion of people the fat provokes inflammation — steatohepatitis — and sustained inflammation lays down scar tissue. Fibrosis is graded from none to cirrhosis, and it is this measure, rather than how bright the liver looks on a scan, that predicts what happens over decades. Progression is slow, typically measured in years per stage, is not inevitable, and is largely preventable. It is also silent, which is why a finding that produces no symptoms is still worth taking seriously.

There is a second reason, less often mentioned in the consultation. The commonest cause of death in people with metabolic fatty liver is cardiovascular disease rather than liver disease. The liver finding is, among other things, a marker of a metabolic state that is affecting the arteries at the same time.

Underneath most cases sits insulin resistance. High circulating insulin instructs the liver to convert surplus carbohydrate into fat — a process called de novo lipogenesis — and impairs its ability to export what it has made. Added fructose is handled almost entirely by the liver and feeds this pathway directly, which is why sugary drinks and packaged juices punch above their weight. This is also why fatty liver arrives alongside a growing waist, a creeping HbA1c, raised triglycerides or PCOS. These are not separate problems that happen to coincide; they are different views of one metabolic picture, and the mechanism itself is set out on the page for insulin resistance.

Body weight is part of the story rather than all of it. Roughly one in five people with fatty liver has a normal BMI, and this lean pattern is common in South Asians, where a normal weight can accompany a high proportion of visceral fat and low muscle mass. A common variation in the PNPLA3 gene, which affects how liver cells handle fat, contributes to fatty liver independently of weight and is well represented in Indian populations.

Alcohol causes a similar-looking liver through a different mechanism, and the conventional threshold used to separate the two sits at around 20 g of alcohol a day for women and 30 g for men — roughly two or three standard drinks. Less commonly, hypothyroidism, PCOS, rapid weight loss, coeliac disease, certain medicines and some inherited conditions contribute. That is why the finding is investigated rather than assumed.

ⓘThis information is educational and not a diagnosis.

Fatty liver is usually silent. Most people are told about it after an ultrasound performed for something else entirely — a routine health check, an insurance screening, an unrelated abdominal pain, a pre-operative assessment.

When there are symptoms, they are vague and easily attributed elsewhere: a dull, non-specific ache or heaviness under the right ribs, tiredness that sleep does not resolve, a sense of fullness after modest meals. None is specific to the liver, and their absence provides no reassurance.

Because the condition is quiet, the risk profile does more work than symptoms. Fatty liver is more likely with weight carried around the abdomen, a family history of type 2 diabetes, PCOS, raised triglycerides or a low HDL, a steadily rising HbA1c, obstructive sleep apnoea, or an underactive thyroid. The Indian thresholds are lower than the international ones: a BMI of 23 is treated as overweight and 25 as obesity in the 2009 Indian consensus, and the waist action points are 90 cm for men and 80 cm for women. Being slim does not exclude the diagnosis.

Two other things are worth recognising. The first is darkened velvety skin at the back of the neck or in the armpits — acanthosis nigricans — which is a visible response to high circulating insulin and is regularly mistaken for a hygiene problem. The second is the alcohol history, which is asked routinely and without judgement, because the amount changes how the finding is classified and what is watched.

If what brought you here is a raised SGPT on a report rather than a scan finding, the sequence of questions is a slightly different one, and it is set out separately on the page for elevated liver enzymes.

The signs below are different in kind. They suggest that the liver's function is affected rather than simply its fat content, and they warrant assessment promptly rather than at the next convenient appointment.

The purpose of testing in fatty liver is not to confirm what the scan already showed. It is to answer three separate questions: how is the liver functioning, why has this happened, and has any scarring begun.

How is it functioning? Liver enzymes — SGPT/ALT and SGOT/AST — indicate cell stress; bilirubin and albumin indicate function. Mildly raised enzymes are common and, on their own, unalarming. The important caveat runs the other way: enzymes are normal in a large proportion of people with fatty liver, including some with established fibrosis, so a normal LFT is not a clearance certificate.

Why has it happened? HbA1c, a fasting lipid profile, blood pressure and waist circumference place the liver finding in its proper context and frequently uncover prediabetes that nobody was looking for. Thyroid function and hepatitis B and C serology exclude the other conditions that produce or accompany a fatty-looking liver, both treatable and neither rare in India. A careful review of medicines and supplements belongs here too.

Has scarring begun? This is the question that decides long-term outlook, and the one most often skipped. FIB-4 is calculated from age, platelet count and the two enzymes — from tests most people have already had, at no extra cost. A value below about 1.3 makes advanced fibrosis unlikely; above about 2.67 raises the question seriously; and the middle band is precisely where a second test is useful. It performs poorly under the age of 35, where it flags too many people, and a higher threshold is used in older adults. Transient elastography measures liver stiffness directly, is available at most large Indian centres as a paid add-on rather than within a standard package, and many machines report a fat measurement alongside the stiffness. A liver biopsy is rarely required in routine practice.

On the ultrasound grade. Grades 1 to 3 describe how bright the liver looks to the person performing the scan. That is a subjective and insensitive measure: it detects little below roughly 20–30% fat content, and it varies between operators and between machines. A grade that has not changed on a repeat scan does not mean nothing has improved, and a grade that has changed may reflect a different radiologist rather than a different liver.

On cost and sequence. An ultrasound is inexpensive and widely available; FIB-4 costs nothing beyond tests already done; HbA1c and lipids are in most health-check packages. That first pass answers the three questions for the majority of people. Elastography and the specialised fibrosis panels earn their place when the first pass leaves the picture unclear or the risk profile is high.

There is no medicine that treats metabolic fatty liver directly. What reverses it is a change in the metabolic conditions that produced it — slower and less satisfying than a prescription, and considerably more effective. What follows is general explanation; decisions about your own medicines belong with your doctor.

Weight, where it applies. The evidence here is unusually clear and worth quoting precisely. Sustained loss of about 5% of body weight clears fat from the liver in most people; around 7–10% improves inflammation; beyond 10% may improve early fibrosis. The word doing the work is sustained. A rate of roughly half a kilogram to a kilogram a week is the range that tends to hold, and rapid crash loss can transiently worsen liver inflammation as well as being regained in most cases.

What is on the plate. The most useful single change for most Indian households is reducing refined carbohydrate and added fructose — sugary drinks, packaged juices, biscuits, sweets — rather than eliminating any staple. Adequate protein at each meal, more fibre and vegetables, and cooking fat kept moderate do more than any specific "liver-friendly" food. A Mediterranean-style pattern has the best evidence, and its Indian translation is recognisable enough: pulses and dal in fuller portions, vegetables occupying more of the plate, nuts and seeds, curd, fish where it is eaten, olive or mustard oil in moderate quantity, and rice or roti kept as a measured part of the meal rather than its bulk. Two or three cups of coffee a day are associated with less liver fibrosis in observational studies — an unusually pleasant piece of evidence, and not a reason to start if you do not drink it.

Movement, including resistance work. Exercise improves liver fat even where weight does not change, which matters for lean fatty liver. A practical target is 150 minutes a week of moderate aerobic activity plus two sessions of resistance training, built up gradually from wherever you are now. Muscle is where most glucose is disposed of, so building it addresses the mechanism rather than only the calories.

Alcohol. Where fatty liver is present, alcohol adds a second injury to a liver already under load. While the picture is being sorted out, the safest amount is none.

Sleep, and sleep apnoea. Short sleep worsens insulin resistance measurably, and obstructive sleep apnoea is both common in this group and frequently undiagnosed. Snoring with daytime sleepiness is worth raising.

What is treated with medicine is the company fatty liver keeps — diabetes, dyslipidaemia, hypothyroidism, obstructive sleep apnoea. Some diabetes medicines, including the GLP-1 receptor agonists and pioglitazone, have useful effects on liver fat and inflammation as more than a side benefit, and a drug directed specifically at the inflamed form has been approved in some countries, with availability in India still limited. Vitamin E has a role in selected people without diabetes, decided case by case. Statins deserve a specific mention: they are prescribed less often than they might be in people with fatty liver, out of a concern about the liver that the evidence does not support, and where cardiovascular risk is the larger threat that withholding matters. Metabolic surgery is considered for a defined group. Vaccination against hepatitis A and B is reasonable in anyone with chronic liver disease who is not already immune. Over-the-counter liver tonics and detox regimens have no evidence behind them, and some herbal and ayurvedic preparations are themselves recognised causes of liver injury in Indian registries. Every one of these is an individual decision with a doctor who knows your history.

Follow-up is what makes any of this real. Repeat liver enzymes and metabolic markers at three to six months, reassess fibrosis risk while risk factors persist, and treat a plateau as information about the plan rather than a verdict on the person following it.

Fatty liver is one of those diagnoses where understanding the mechanism changes what you do about it. Once it is clear that the liver is responding to a metabolic signal rather than to a poison, the plan stops being about avoiding foods and starts being about changing the signal — and the scan grade stops being the number you watch.

If the underlying question is why any of this began, insulin resistance is the mechanism beneath it, and prediabetes is what the same process looks like once the glucose number has moved.

If you would like to work through the specifics — what the grades mean, how to read your own LFT, how fibrosis is assessed, and what a realistic first three months looks like — the Learning Session below covers it in a small group with time for questions.

If you already have reports in hand and want them interpreted against your own history, weight trend and family background, that is a conversation for a consultation rather than an article.