Can I eat before undergoing a liver function test?
Jul 28, 2025
Source: Cainiu Health
Dr. Gao Jun
Introduction
Under normal circumstances, you should not eat before undergoing a liver function test, as this may affect the test results. Liver function tests require fasting, and generally, you should not consume any food for 8-12 hours prior to the examination. The evening before the test, you should eat lightly and avoid alcohol, spicy, or greasy foods. On the morning of the test, in addition to not eating, you should also try to avoid drinking water; if you are truly thirsty, you may drink a small amount of warm boiled water.
Generally, you should not eat before undergoing a liver function test to avoid affecting the test results. Detailed explanations are as follows:
Liver function tests primarily measure indicators in the serum such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), bilirubin, and albumin, all of which can be influenced by diet. After eating, the digestive system becomes active and the liver participates in the metabolism and digestion of food, increasing liver cell activity and causing temporary elevations in enzyme levels such as ALT and AST. Additionally, eating, especially foods high in fat or protein, may alter serum components like triglycerides, interfering with the measurement of indicators such as bilirubin and affecting the physician's accurate assessment of liver function.
In addition to requiring fasting, liver function tests generally require no food or drink (except water) for 8–12 hours before the test. On the evening before the test, you should eat lightly and avoid alcohol, spicy food, or greasy meals. On the morning of the test, you should not eat anything and should also limit water intake, although small sips of plain water are acceptable if you are extremely thirsty. Furthermore, you should ensure adequate sleep before the test and avoid strenuous exercise to prevent fluctuations in your physical condition that could affect the test results.
