Background <p>The distribution of diet-attributable cancer burden has not been systematically analyzed globally. This study aimed to analyze the diet-attributable cancer burden using the Global Burden of Disease (GBD) database to provide insights into reducing the dietary risk-related cancer burden across regions with different development levels.</p> Methods <p>Data on cancer deaths and disability-adjusted life years (DALYs) attributable to diet were downloaded from the GBD database (1990–2021). The cancer burden attributable to nine dietary factors and total dietary factors was sorted, and Joinpoint regression analysis was performed according to the Socio-Demographic Index (SDI) regions. Then, using the DALYs data, a health inequality analysis was conducted, and the Slope Index of Inequality (SII) and concentration indices (CI) for 1990 and 2021 were calculated.</p> Results <p>From 1990 to 2021, the global cancer burden attributed to diet decreased continuously, with an average annual percentage change (AAPC) of -1.40 (-1.48, -1.32) for mortality (<i>P</i> &lt; 0.01) and an AAPC of -1.49 (-1.57, -1.42) for DALYs (<i>P</i> &lt; 0.01). Colon and rectal cancers were the most influenced by dietary factors, with diet-attributable deaths comprising 71.70% and 68.14% of total deaths in 1990 and 2021, respectively, followed by breast and stomach cancers, which both exceeded 40% in both years. The diet-related cancer burden decreased rapidly in the high and high-middle SDI regions with AAPCs for both mortality and DALYs being less than 0 (<i>P</i> &lt; 0.01). In contrast, there was Little improvement in the low- and low-middle SDI regions. In 2021, the absolute values of the SII (296.72) and CI (-0.17) attributed to global dietary risks were higher than those in 1990 with the SII of 267.61 and CI of -0.17.</p> Conclusion <p>Dietary factors continued to be a significant risk factor for cancer in 2021. High red meat consumption, low intake of whole grains, and low milk intake were the three primary dietary risks.</p>