Fatty Liver Disease: Prevention, Diagnosis, and When to See a Doctor

Fatty liver disease belongs to those conditions where prevention and treatment essentially coincide: nutrition, weight control, and regular activity work at both stages. The greatest difficulty is detecting the disease in time and correctly assessing how much it threatens the liver. The editorial team explains which steps really reduce the risk, which studies are needed, and when a doctor cannot be avoided.

Prevention: nutrition, weight, training

The basis of prevention of fatty liver disease is maintaining an energy balance and a healthy waist circumference. For people with excess body weight, weight loss is the most effective intervention. In the study by Vilar-Gomez and co-authors (2015), a loss of 5% of body weight reduced steatosis, 7–10% was associated with regression of steatohepatitis, and 10% or more — with improvement of fibrosis.

The composition of the diet also matters. Clinical guidelines recommend limiting added sugar and especially sweet drinks and juices as the main source of fructose, cutting ultra-processed products, and favoring a Mediterranean type of diet with vegetables, legumes, whole grains, fish, and olive oil (EASL-EASD-EASO, 2016).

With existing fatty liver disease, alcohol is best minimized or eliminated: even moderate amounts additionally burden the liver and accelerate progression. For athletes this especially concerns the tradition of “celebrating” competitions.

Regular physical activity reduces the fat content in the liver regardless of weight loss. Guidelines aim for 150–300 minutes of moderate aerobic activity per week, supplemented by strength training. For people who already train, it is important to keep active even during periods of injury or breaks, adapting nutrition to the reduced expenditure.

• with excess weight — a gradual reduction of 7–10% over a few months, without fasting;
• a minimum of sweet drinks, juices, and gainers with simple sugars;
• limiting or giving up alcohol;
• aerobic and strength training every week, including during the off-season;
• caution with herbal “fat burners” and supplements of unknown composition.

Who should get examined

Fatty liver disease gives almost no symptoms, so the emphasis is on a targeted search in risk groups. Modern guidelines recommend assessing the state of the liver in people with obesity or excess weight, type 2 diabetes, metabolic syndrome, as well as in those who have incidentally been found to have elevated liver enzymes or signs of steatosis on ultrasound.

For athletes it is appropriate to undergo an examination if the waist circumference is increasing, especially during a period of mass gain; if the tests show elevated triglycerides or fasting glucose; if anabolic steroids, growth hormone, or long courses of glucocorticoids were used in the past; as well as with regular alcohol consumption.

Former strength-sport athletes after finishing their careers are a separate group for attention. The high caloric content of the diet in combination with a reduction in activity quickly changes the metabolic profile, and a preventive examination during this period makes sense.

Finally, it is worth getting examined if there is diabetes or liver disease in the family, as well as when taking drugs associated with steatosis.

Methods of diagnosis

Standard biochemical tests include ALT, AST, GGT, alkaline phosphatase, bilirubin, as well as a lipid panel, fasting glucose, and glycated hemoglobin to assess the metabolic background. It is important to understand: normal liver enzymes do not rule out fatty liver disease, and elevated ones do not prove it.

In athletes biochemistry has an additional trap. ALT and AST are also found in muscles, so after heavy strength training they can rise and remain elevated for a week (Pettersson et al., 2008). To avoid a false alarm, before the test it is worth taking a break of a few days from heavy loads and at the same time taking creatine kinase and GGT.

Ultrasound examination is the most accessible method for detecting steatosis. It sees moderate and pronounced fat accumulation well, but it may miss mild steatosis and does not assess fibrosis. Fat can be quantified more precisely by the controlled attenuation parameter (CAP) during elastography and by MRI with proton density fat fraction assessment.

The doctor also rules out other causes of liver damage: viral hepatitis B and C, excessive alcohol consumption, the toxic effect of drugs and supplements, hemochromatosis, autoimmune and other rare diseases. A liver biopsy is performed rarely — only when non-invasive methods do not give an unambiguous answer.

Assessment of fibrosis: FIB-4 and elastography

The prognosis in fatty liver disease is determined not by the amount of fat but by the stage of fibrosis. So after detecting steatosis, the next step is to assess the risk of pronounced fibrosis. As a first stage, the guidelines recommend the simple calculated FIB-4 index.

FIB-4 is calculated from age, the level of AST and ALT, and the platelet count (Sterling et al., 2006). A value below 1.3 indicates a low probability of pronounced fibrosis, above 2.67 — a high one, and intermediate values require clarification. For athletes it is important that AST and ALT for the calculation be determined after rest, otherwise the index will be falsely overstated.

With intermediate or high FIB-4 values, transient elastography of the liver is performed, which measures the stiffness of the tissue. The combination of two non-invasive methods allows a biopsy to be avoided in most cases and makes it possible to determine who needs observation by a hepatologist.

People with a low risk according to the assessment results usually receive recommendations regarding lifestyle and a repeat check in a few years, while those with pronounced fibrosis — regular observation, including monitoring for complications of cirrhosis.

When to see a doctor

A scheduled consultation with a general practitioner or gastroenterologist is needed if ultrasound has detected steatosis, liver enzymes are persistently elevated after rest from training, there is diabetes, obesity, or metabolic syndrome, or you have used anabolic steroids, growth hormone, or glucocorticoids for a long time.

A referral to a hepatologist is usually received by patients with a FIB-4 above 2.67 or with increased liver stiffness on elastography, as well as in the presence of other possible causes of liver damage.

Emergency attention should be sought at the appearance of jaundice (yellowing of the skin and whites of the eyes), dark urine and light-colored stool, pronounced itching, enlargement of the abdomen, bloody vomiting or black stool, and confusion. These symptoms are not characteristic of simple steatosis and may indicate acute toxic damage, cholestasis, or complications of cirrhosis — in particular against the background of taking oral steroids or supplements.

There are few specific drugs for treating fatty liver disease, and they are prescribed by a doctor. “Hepatoprotectors” and detox agents without proven efficacy do not replace lifestyle changes.

Editorial conclusions

Prevention of fatty liver disease is the control of body weight and waist, limiting sugar, sweet drinks, and alcohol, and regular training. With excess weight, reducing it by 7–10% gives a measurable effect for the liver.

Diagnosis includes biochemical tests, ultrasound, and a mandatory assessment of fibrosis by FIB-4 with subsequent elastography if needed. Athletes should take liver tests after a few days without heavy training and together with creatine kinase.

Jaundice, dark urine, itching, or enlargement of the abdomen are grounds for an emergency visit, while persistent abnormalities in the tests — for a scheduled consultation.

We also recommend reading our articles on the causes of fatty liver disease in athletes, on the liver tests ALT and AST, and on creatine kinase after training.

References

1. European Association for the Study of the Liver (EASL), European Association for the Study of Diabetes (EASD), European Association for the Study of Obesity (EASO). EASL-EASD-EASO Clinical Practice Guidelines for the management of non-alcoholic fatty liver disease. J Hepatol. 2016;64(6):1388–1402.
2. Chalasani N, Younossi Z, Lavine JE, et al. The diagnosis and management of nonalcoholic fatty liver disease: practice guidance from the American Association for the Study of Liver Diseases. Hepatology. 2018;67(1):328–357.
3. Vilar-Gomez E, Martinez-Perez Y, Calzadilla-Bertot L, et al. Weight loss through lifestyle modification significantly reduces features of nonalcoholic steatohepatitis. Gastroenterology. 2015;149(2):367–378.
4. Sterling RK, Lissen E, Clumeck N, et al. Development of a simple noninvasive index to predict significant fibrosis in patients with HIV/HCV coinfection. Hepatology. 2006;43(6):1317–1325.
5. Pettersson J, Hindorf U, Persson P, et al. Muscular exercise can cause highly pathological liver function tests in healthy men. Br J Clin Pharmacol. 2008;65(2):253–259.
6. Rinella ME, Lazarus JV, Ratziu V, et al. A multisociety Delphi consensus statement on new fatty liver disease nomenclature. J Hepatol. 2023;79(6):1542–1556.