Most people with a fatty liver have no idea they have one. The condition rarely causes obvious symptoms in its early stages, and it’s frequently discovered by accident during routine blood work or an imaging scan done for something else entirely. Up to 5% fat in the liver is considered normal, but once fat exceeds that threshold, it qualifies as fatty liver disease, now officially called metabolic dysfunction-associated steatotic liver disease (MASLD).
So if you can’t feel it, how would you know? The answer involves a combination of risk factors, blood tests, and imaging, along with a few subtle clues your body might be giving you.
Why Most People Feel Nothing
Fatty liver often has no symptoms at all. When symptoms do appear, they tend to be vague: persistent fatigue and a general sense of not feeling well. There’s no sharp pain that points to the liver, no obvious skin change in early stages, and no digestive problem that screams “liver issue.” This is partly why the condition is so underdiagnosed. The liver can accumulate significant fat, even develop inflammation, before you notice anything wrong.
Some people with an enlarged liver feel a dull ache or sense of fullness in the upper right side of the abdomen, just below the ribs. But this is more common in advanced disease and isn’t reliable as an early warning sign.
Risk Factors That Raise the Odds
Your body measurements and metabolic health are the strongest clues. A diagnosis of MASLD requires both fat in the liver and at least one of five cardiometabolic risk factors:
- Elevated BMI or waist circumference: A BMI of 25 or higher, or a waist circumference greater than 94 cm (37 inches) for men or 80 cm (31.5 inches) for women.
- Blood sugar problems: Fasting blood sugar at or above 100 mg/dL, an A1C of 5.7% or higher, or a type 2 diabetes diagnosis.
- High blood pressure: Readings at or above 130/85 mmHg, or taking blood pressure medication.
- High triglycerides: Levels at or above 150 mg/dL, or taking lipid-lowering medication.
- Low HDL cholesterol: Below 40 mg/dL for men or below 50 mg/dL for women.
If you check even one of those boxes, you’re in the risk pool. A useful rule of thumb that works across different ethnicities and age groups: if your waist circumference is more than half your height, your risk of fatty liver climbs sharply. Research using large population data found that a waist-to-height ratio above roughly 0.52 in men and 0.53 in women was the optimal threshold for identifying people likely to have significant liver fat.
What Blood Tests Can (and Can’t) Tell You
Standard liver function tests measure enzymes like ALT and AST. Normal ALT runs between 7 and 55 units per liter, and normal AST between 8 and 48 units per liter. When these numbers come back elevated on routine blood work, your doctor will often investigate further, and fatty liver is one of the most common explanations.
Here’s the catch: many people with fatty liver have completely normal liver enzymes. An ALT in the normal range does not rule out the condition. Blood tests are a useful flag when they’re abnormal, but a normal result doesn’t mean your liver is clear.
Doctors also use a calculated score called the FIB-4 index, which combines your age, platelet count, and liver enzyme levels into a single number that estimates whether your liver has developed scarring (fibrosis). A FIB-4 score below 1.45 is reassuring, with a 90% chance of ruling out advanced fibrosis. A score above 3.25 is a strong signal that significant scarring may be present. Scores between those numbers fall into a gray zone that typically calls for further testing.
How Imaging Confirms the Diagnosis
The most common way fatty liver gets confirmed is through imaging. A standard abdominal ultrasound can detect fat in the liver when there’s enough of it, and it’s often the first imaging test ordered because it’s inexpensive and widely available. However, ultrasound is less reliable at detecting mild fat accumulation and can’t precisely measure how much fat is present.
A more specialized tool called FibroScan (liver elastography) measures both liver fat and liver stiffness in a single, painless appointment that takes about 10 minutes. It produces a CAP score that grades the amount of fat:
- Below 238 dB/m: Normal (no more than 5% fatty change)
- 238 to 260 dB/m (Grade S1): Mild, affecting less than one-third of the liver
- 260 to 290 dB/m (Grade S2): Moderate, affecting one-third to two-thirds
- 290 to 400 dB/m (Grade S3): Severe, affecting more than two-thirds
The stiffness measurement from the same scan gives your doctor an estimate of fibrosis, which is the more dangerous consequence of long-term fatty liver. Fat alone is reversible. Scarring is harder to undo.
For the most precise measurement of liver fat, a specialized MRI technique can quantify the exact fat percentage. It correlates almost perfectly with the gold-standard laboratory method and can detect fat content as low as 5.56%, which is the threshold where normal tips into abnormal. MRI-based fat measurement is typically reserved for clinical trials or cases where other tests are inconclusive.
Physical Signs Worth Paying Attention To
There’s one visible skin change that correlates with liver fat, particularly in people with insulin resistance or type 2 diabetes. Acanthosis nigricans is a patch of thickened, darkened, velvety skin that appears most often on the back of the neck but can also show up in the armpits, elbows, knees, or groin. It’s a marker of insulin resistance, and research in people with type 2 diabetes found that those with acanthosis nigricans had significantly higher liver fat scores and greater liver stiffness than those without it. The adjusted odds of liver fibrosis were roughly 2.5 times higher in the group with this skin finding.
This doesn’t mean the skin change proves you have fatty liver. But if you notice dark, velvety patches on your neck or underarms and you also carry extra weight around the middle, it’s a signal your metabolism is under strain in ways that commonly include liver fat accumulation.
When Fatty Liver Progresses to Something Worse
Fat sitting quietly in the liver (simple steatosis) is the earliest and most common stage. In some people, the liver becomes inflamed, a condition now called MASH (metabolic dysfunction-associated steatohepatitis, formerly NASH). MASH is the stage where real damage begins, because ongoing inflammation leads to fibrosis.
The symptoms of progression are still frustratingly subtle. Worsening fatigue, unexplained itching, or the appearance of small spider-like blood vessels on the skin can suggest the liver is under increasing stress. By the time more obvious signs appear, like yellowing skin, easy bruising, or fluid buildup in the abdomen, the disease has typically advanced to cirrhosis.
A liver biopsy remains the most definitive way to determine whether simple fat has progressed to active inflammation and scarring. A pathologist scores the tissue sample on a scale of 0 to 8 based on how much fat, inflammation, and cell damage is visible. Biopsies aren’t routine for everyone with fatty liver, though. They’re generally reserved for people whose non-invasive tests suggest advancing disease or when there’s uncertainty about the diagnosis.
The Practical Path to Finding Out
If you’re wondering whether you have a fatty liver, the most straightforward starting point is looking at your own risk profile. Do you carry weight around your midsection? Is your waist more than half your height? Have you been told your blood sugar, triglycerides, or blood pressure are creeping up? If yes, the probability is meaningfully higher than average.
From there, a simple blood panel that includes liver enzymes and a calculated FIB-4 score can provide an initial screen. If enzymes are elevated or your FIB-4 falls in the intermediate or high range, imaging with ultrasound or FibroScan gives a clearer picture. The whole process is non-invasive, and for most people, the answer comes without anything more complicated than a blood draw and a scan.