Non-Alcoholic Fatty Liver Disease and How to Prevent It

A healthy diet may reduce your risk

Non-Alcoholic Fatty Liver Disease, or NAFLD, is on the rise in the United States thanks to a huge increase in obesity rates over the last three decades. In industrialized countries, 20-40% of the general population has some form of fatty liver disease and the chances of its progressing increase with age.

Officially recognized as a disease in the early 1980s, non-alcoholic fatty liver disease perplexed the medical community. Obese and diabetic patients had elevated liver enzymes and enlarged livers virtually identical to those typically seen in alcoholics, but most of them insisted they were not drinking excessively.

Overweight woman buttoning up her jeans
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Liver Function Basics

The liver is your largest internal organ. It performs hundreds of functions including:

  • processing everything you eat and drink
  • pulling toxins from your blood
  • fighting off infection
  • controlling blood sugar levels
  • helping to manufacture hormones and proteins


The liver normally weighs about three pounds. When more than 5-10% of your liver’s weight is fat, you have a “fatty liver.” While excess liver fat, or steatosis, causes no problems for some, it can cause symptoms of impaired liver function, including:

  • fatigue
  • nausea
  • abdominal pain
  • yellowing skin or eyes (as in jaundice)

Inflammation that causes scarring is a hallmark symptom of liver injury in advanced non-alcoholic fatty liver disease, which can lead to cirrhosis. Once you damage your liver, your body lays down collagen to repair it. Fibrosis or thickening of the liver tissue then ensues.

As the non-alcoholic fatty liver disease progresses, about 10% of cases will develop over the next ten years into the much more serious NASH or nonalcoholic steatohepatitis. NASH can lead to:


An accurate diagnosis of non-alcoholic liver disease is the first step towards treating this, sometimes, serious health condition. Your physician will usually diagnose fatty liver disease by:

  • administering tests to detect elevated liver enzymes
  • ordering an ultrasound to determine if you have an enlarged liver
  • performing a  liver biopsy to determine whether you have NASH or simple fatty liver

Risk Factors

Though the exact causes of NAFLD are not known, patients have some pre-existing conditions in common, including:

What’s more, the severity of NAFLD increases with the degree of obesity, and abdominal or belly fat seems to increase the risk of dangerous NASH, even in patients with a body mass index (BMI) in the normal range.

BMI is a dated, flawed measure. It does not take into account factors such as body composition, ethnicity, sex, race, and age. 
Even though it is a biased measure, BMI is still widely used in the medical community because it’s an inexpensive and quick way to analyze a person’s potential health status and outcomes.

Dietary Considerations

What you eat and the nutrition it provides contributes to the onset, progression, and treatment of NAFLD. Dietary factors that increase your risk include consuming:

  • a high-calorie diet
  • a diet rich in hydrogenated oil (trans fats)
  • too much protein from animal sources, resulting in a high intake of saturated fat and cholesterol
  • too many beverages sweetened with high fructose corn syrup

Dietary factors that reduce your risk of NAFLD include:

  • consuming fewer calories
  • eating protein from whey or vegetable sources, instead of from meat and cheese
  • losing 3 to 10 percent of your bodyweight
  • adding fiber, green tea, and coffee to your diet
9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Benedict M, Zhang X. Non-alcoholic fatty liver disease: An expanded reviewWorld J Hepatol. 2017;9(16):715–732. doi:10.4254/wjh.v9.i16.715

  2. Hassan K, Bhalla V, El Regal ME, A-Kader HH. Nonalcoholic fatty liver disease: a comprehensive review of a growing epidemicWorld J Gastroenterol. 2014;20(34):12082–12101. doi:10.3748/wjg.v20.i34.12082

  3. [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG). How does the liver work? Available from:

  4. Chan SC, Liu CL, Lo CM, et al. Estimating liver weight of adults by body weight and genderWorld J Gastroenterol. 2006;12(14):2217–2222. doi:10.3748/wjg.v12.i4.2217

  5. Neuman MG, Cohen LB, Nanau RM. Biomarkers in nonalcoholic fatty liver diseaseCan J Gastroenterol Hepatol. 2014;28(11):607–618.

  6. Calzadilla Bertot L, Adams LA. The Natural Course of Non-Alcoholic Fatty Liver DiseaseInt J Mol Sci. 2016;17(5):774. doi:10.3390/ijms17050774

  7. Jennison E, Patel J, Scorletti E, Byrne CD. Diagnosis and management of non-alcoholic fatty liver disease. Postgrad Med J. 2019;95(1124):314-322.

  8. Stefan N, Häring HU, Cusi K. Non-alcoholic fatty liver disease: causes, diagnosis, cardiometabolic consequences, and treatment strategies. Lancet Diabetes Endocrinol. 2019;7(4):313-324.

  9. Jeznach-Steinhagen A, Ostrowska J, Czerwonogrodzka-Senczyna A, Boniecka I, Shahnazaryan U, Kuryłowicz A. Dietary and Pharmacological Treatment of Nonalcoholic Fatty Liver DiseaseMedicina (Kaunas). 2019;55(5):166. doi:10.3390/medicina55050166

Additional Reading
  • Fatty Liver Disease. Canadian Liver Foundation Public Information Sheet.

  • Lazo, et al. “Non-alcoholic fatty liver disease and mortality among US adults: prospective cohort study.” BMJ. 2011 Nov 18;343:d6891.

  • Non-alcoholic Fatty Liver Disease (NAFLD). American Liver Foundation Public Information Sheet.

  • Nonalcoholic Steatohepatitis. US Department of Health and Human Services Public Information Sheet.

  • Angulo, Paul, and Lindor, Keith. Non-alcoholic Fatty Liver Disease. Journal of Gastroenterology and Hepatology (2002) 17 (Suppl.) S186–S190.
  • Ludwig, et al. Nonalcoholic steatohepatitis: Mayo Clinic experiences with a hitherto unnamed disease. Mayo Clin Proc 1980; 55:434-8.

By Sharon Basaraba
Sharon Basaraba is an award-winning reporter and senior scientific communications advisor for Alberta Health Services in Alberta, Canada.