Dietary habits significantly influence the development of intestinal diverticular disease (IDD), a common gastrointestinal condition primarily affecting the colon. We performed a Mendelian randomization (MR) analysis on 20 diet-related factors using data from the UK Biobank. IDD cases ( = 33,618) and controls ( = 329,381) were obtained from the FinnGen Biobank. Three key MR methods were applied: the inverse-variance-weighted (IVW) method as the primary approach to estimate causal relationships, along with the weighted median (WM) and MR-Egger methods. Significant associations were found for pork intake ( = 1.06,  = 0.00244), nonoily fish intake ( = 0.709,  = 0.0449), oily fish intake ( = 0.246,  = 0.0222), and dried fruit intake ( = -0.953,  < 0.0001). After false discovery rate (FDR) adjustment, pork intake ( = 0.0244) and dried fruit intake ( < 0.0001) remained significant. Our results indicate that while pork and certain types of fish intake may elevate the risk of IDD, dried fruit intake may offer a protective effect. These findings highlight the potential of dietary changes in IDD prevention and management, though further research across diverse populations is needed.