Basic characteristics of included literature.

BackgroundThe Dietary Inflammatory Index (DII) is a literature-based tool designed to predict inflammation. Previous studies suggest a potential association between the DII and non-alcoholic fatty liver disease (NAFLD). However, the relationship between the DII and both the incidence and progression of NAFLD remains unclear.MethodsSystematic literature searches were conducted in PubMed, Web of Science, Embase, Scopus, and the Cochrane Library up to July 2025. A random-effects model was applied, and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Sensitivity and subgroup analyses were performed to explore the sources of heterogeneity, while Egger’s test was used to assess publication bias. Review Manager 5.4 and STATA 15.0 were employed for statistical analysis.ResultsEighteen studies involving 262,468 participants were included. The data indicated a significant association between the DII and NAFLD (OR = 1.33, 95% CI: 1.23–1.44; P ConclusionA high DII was associated with an increased risk of NAFLD and an increased risk of progression to fibrosis.Systematic review registrationPROSPERO, identifier CRD42025632168.