Ischemic heart disease (IHD) remains a leading cause of death worldwide, with dietary risks being its most significant modifiable factor. Here, using the Global Burden of Diseases, Injuries and Risk Factors Study 2023, we estimated the mortality and disability-adjusted life years from diet-related IHD across 204 countries. In 2023, a suboptimal diet was responsible for 4.06 million (95% uncertainty interval (UI) 0.74-6.22) IHD deaths and 96.84 million (18.82-142.52) IHD disability-adjusted life years. The global age-standardized death rate of IHD attributable to suboptimal diet decreased by 43.92% (95% UI 34.44-53.23) per 100,000 population from 1990 to 2023. Among dietary factors, low intake of nuts and seeds (9.87, 95% UI 2.84-17.12 deaths per 100,000 population), low whole grains (9.22, 4.73-13.67), low fruits (7.25, 1.54-13.34) and high sodium (7.15, 0.92-17.97) were primary contributors to IHD deaths. The burden was particularly pronounced in low- and middle-sociodemographic index countries. By disentangling dietary risk factors, we identified the portion of IHD burden directly modifiable through food interventions.