Fatty liver: what your liver tests may be telling you

Many people first hear about fatty liver by surprise. A checkup blood test shows "elevated liver enzymes," or an ultrasound ordered for something else says "hepatic steatosis." You feel fine, so the news can be confusing. Fatty liver is very common in Los Angeles and across the country, and for most people it can be managed. The key is understanding what your tests show and checking whether the liver has any scarring.

What is fatty liver?

Your liver normally holds a little fat. Fatty liver means extra fat has built up inside the liver cells. When this happens in someone with metabolic risk factors, such as extra weight around the waist, type 2 diabetes or prediabetes, high blood pressure, or high triglycerides (a blood fat), doctors now call it MASLD: metabolic dysfunction-associated steatotic liver disease. You may also see the older name, NAFLD (nonalcoholic fatty liver disease). They describe nearly the same condition.

For many people, MASLD stays mild. In some, the extra fat causes inflammation and liver cell injury, called MASH (metabolic dysfunction-associated steatohepatitis). Over years, ongoing inflammation can lead to fibrosis, which is scarring of the liver. Severe scarring is called cirrhosis. Most people with fatty liver never reach that point, and finding it early gives you time to change the course.

Fatty liver usually causes no symptoms. Some people notice tiredness or a dull ache in the upper right belly, but most feel completely normal. That is why the condition is so often found by accident. You can read a broader overview on our fatty liver disease page.

ALT and AST in plain words

ALT (alanine aminotransferase) and AST (aspartate aminotransferase) are enzymes, proteins that help liver cells do their work. When liver cells are irritated or injured, some of these enzymes leak into the blood. A blood test measures them, often as part of a routine "metabolic panel."

• Mildly high ALT and AST are common in fatty liver. They tell you the liver is irritated, but not how much fat or scarring there is.
• Normal ALT and AST do not rule out fatty liver. Many people with fatty liver, and even some with scarring, have normal enzyme levels.
• Other causes matter. Alcohol, some medicines and supplements, hepatitis B and C, iron overload, autoimmune liver disease and thyroid problems can also raise liver enzymes. Part of an evaluation is making sure nothing else is going on.

Your report may also include bilirubin, alkaline phosphatase, albumin and a platelet count. Each gives a different clue about how the liver is working. Bring copies of past results to your visit, because the trend over time is often more useful than one number.

What does "fatty liver" on an ultrasound mean?

An ultrasound uses sound waves to make pictures. Fat makes the liver look brighter than normal, so the report may say "increased echogenicity," "hepatic steatosis" or "fatty infiltration." This confirms that fat is present, and it is a helpful first step.

What a standard ultrasound cannot do well is measure scarring. A liver with fat alone and a liver with fat and scarring can look similar. That is why doctors use another step to estimate fibrosis.

What is a FIB-4 score, and why does scarring matter?

Among people with fatty liver, the amount of scarring is the most important predictor of long-term liver health. Fat alone usually does not cause serious problems. Advancing fibrosis is what raises the risk of cirrhosis and liver cancer over time.

The FIB-4 index is a simple score calculated from four things you may already have: your age, AST, ALT and platelet count. No extra test is needed. National liver guidance from the American Association for the Study of Liver Diseases (AASLD) uses it as a first screen:

Low score

Advanced scarring is unlikely. Focus on healthy habits and recheck over time.

Middle score

The result is uncertain. A second test is usually recommended.

High score

Scarring is more likely. Further testing and closer follow-up are recommended.

The second test is often a special ultrasound that measures how stiff the liver is (elastography, such as FibroScan), or a blood test designed to estimate fibrosis. Stiffer tissue usually means more scarring. A liver biopsy is rarely needed today. Your plan depends on your health; Dr. Pimienta will talk with you about what fits you.

Fatty liver in Latino communities

Fatty liver affects people of every background. According to the National Institutes of Health (NIDDK), it is most common among Hispanic individuals in the United States. Experts think genes play a part: a common variant in a gene called PNPLA3 makes it easier for fat to build up in the liver, and it is found more often in people of Latin American ancestry. Higher rates of diabetes and prediabetes also contribute.

This is not about blame. You cannot change your genes, and many people with these risk factors live healthy lives. It does mean that Latino adults in Los Angeles County with diabetes, prediabetes or extra weight around the waist have good reason to ask their doctor about their liver. Getting care in Spanish can make it easier to ask questions and involve family members who cook and shop for the household. Dr. Pimienta speaks English and Spanish.

What helps your liver?

The good news is that the liver can heal. Fat can go away, inflammation can settle, and early scarring can sometimes improve. What helps most:

• Gradual weight loss, if you carry extra weight. According to the NIH, losing at least 3 to 5% of your body weight can reduce liver fat, and losing 7 to 10% may be needed to reduce inflammation and scarring. Slow and steady is safer than crash dieting.
• Eating patterns, not perfection. A Mediterranean-style pattern (vegetables, beans, whole grains, fish, olive oil, nuts) is often recommended. Cutting back on sugary drinks, juice and highly processed foods helps a lot.
• Moving more. Regular activity helps the liver even without weight loss. A brisk walk counts.
• Limiting or avoiding alcohol. Alcohol and fatty liver add up. If there is scarring, avoiding alcohol completely is usually advised.
• Treating diabetes, blood pressure and cholesterol. These affect the liver and the heart, and heart disease is a leading health risk for people with MASLD.
• Checking your medicines and supplements. Some herbal products can harm the liver. Bring everything you take to your visit.

For some people, medicine is part of the plan. Certain diabetes and weight medicines, including GLP-1 medicines, can help with weight and liver fat, and the FDA has recently approved the first medicines specifically for MASH with moderate to advanced scarring. These are for specific situations, and healthy habits remain the foundation. If you would like support with weight, Dr. Pimienta is board-certified in obesity medicine and offers medical weight management. If you are starting a GLP-1 medicine, our article on GLP-1 medicines and your digestion explains common side effects.

When to see a GI doctor

Consider a visit with a gastroenterologist if you have been told you have fatty liver, if your liver enzymes have been high on more than one test, if your FIB-4 score is in the middle or high range, or if you have diabetes or prediabetes along with fatty liver. Yellowing of the skin, swelling of the belly or legs, or easy bruising are reasons to be seen soon. If you also have ongoing pain in the upper belly, our abdominal pain page explains other possible causes.

Dr. Pimienta sees adults from across Los Angeles County, in person at the Wilshire office near the Miracle Mile or by secure video for patients in California. Bring your recent blood tests and imaging reports. To get started, request an appointment and the team will call you back.

References

1. American Association for the Study of Liver Diseases. AASLD Practice Guidance on the Clinical Assessment and Management of Nonalcoholic Fatty Liver Disease. Hepatology, 2023.
2. National Institute of Diabetes and Digestive and Kidney Diseases. Definition and Facts of NAFLD and NASH.
3. National Institute of Diabetes and Digestive and Kidney Diseases. Treatment for NAFLD and NASH.
4. U.S. Food and Drug Administration. FDA Approves First Treatment for Patients with Liver Scarring Due to Fatty Liver Disease. 2024.