Objectives <p>A suboptimal diet is a key preventable risk factor for many diseases. This study aimed to evaluate the burden of all-cause death attributed to dietary risks in Iran.</p> Methods <p>We used the Global Burden of Disease data to estimate the temporal trends of age-standardized rates of years of life lost (YLLs) and years of healthy life lost due to disability (YLDs) due to diet-related factors from 2000 to 2021, segmented by sex and province in Iran. Join point regression was used for these analyses.</p> Results <p>The trend analysis indicated that the highest average annual percent change (AAPC) of YLDs for dietary risks in women was attributable to high red meat consumption (3.8, 95% UI; 3.7, 3.9) and in men was attributable to a low intake of nuts and seeds (-3.3, 95% UI; -3.4, -3.2). The highest AAPC of YLLs for dietary risks in women (-5.7, 95% UI; -5.8, -5.6) and men (-5.42, 95% UI; -5.54, -5.26) were attributable to low intake of nuts and seeds. The highest rate of diet-related YLDs was in Khuzestan (264 per 100,000) and Khorasan-e-Razavi provinces (262 per 100,000) for women and men, respectively. Golestan province had the highest rate of diet-related YLLs in women (2043 per 100,000) and men (3059 per 100,000).</p> Conclusion <p>This research provides a detailed overview of how dietary risks could affect disease burden. Highlights the importance of the need for evidence-based nutritional policies aimed at improving dietary quality, reducing disease risk in Iran.</p>