Purpose <p>To investigate whether there is any effect of preprandial and postprandial states of patients on Ultrasound-derived fat fraction(UDFF) in liver fat content measurement.</p> Methods <p>A retrospective study was conducted on 1596 patients who underwent UDFF from January to September 2024; UDFF measurements were performed by a sonographer, who repeated each measurement 5 times before and after meals, respectively, and finally expressed them as the mean; then paired t-tests and analyses of variance (ANOVA) were used to compare the differences in preprandial and postprandial UDFF and Auto p-SWE( Auto point shear wave elastography) values among groups, and linear regression was used to analyze the differences in preprandial and postprandial UDFF and Auto p-SWE values between each group.</p> Results <p>The study enrolled 1036 patients(491 males and 545 females), aged 18–89 years, mean age (56.50 ± 14.67) years. The differences in UDFF and Auto p-SWE values between the group eating protein and fatty foods (<i>n</i> = 613) and the group eating light foods (<i>n</i> = 423) were not statistically significant (<i>p</i> &gt; 0.05); the differences in UDFF and Auto p-SWE values between the group with a body mass index(BMI) &lt; 25&#xa0;kg/m2 (<i>n</i> = 703) and the group with a BMI ≥ 25&#xa0;kg/m2 (<i>n</i> = 333) were statistically significant (<i>p</i> &lt; 0.05). Preprandial and postprandiall UDFF and Auto p-SWE values were highly positively correlated in the eating group, the protein and greasy food group, and the light food group (<i>r</i> = 0.985, 0.983, 0.988, <i>r</i> = 0.834, 0.849, 0.810, all <i>p</i> &lt; 0.001).</p> Conclusions <p>UDFF has good consistency in the measurement of liver fat content in preprandial and postprandial states.</p>