Changes in dietary patterns over recent decades have imposed substantial pressure on the environment and natural resources. Consequently, developing a sustainable diet assessment framework capable of simultaneously reducing environmental impacts and economic costs has become increasingly important. In this study, for the first time, the NSGA-II multi-objective optimization algorithm was employed to optimize multiple objectives, including reductions in water consumption, land use, greenhouse gas emissions, terrestrial and freshwater acidification, biodiversity damage, eutrophication potential, total dietary cost, and food waste, while simultaneously satisfying the minimum nutritional requirements for 12 age and sex groups. The optimization results for each age and sex group were presented as a Pareto front, demonstrating the existence of a set of optimal dietary solutions with different trade-offs among the considered objectives. Owing to the inherently multi-objective nature of the problem and the current structure of food prices, identifying a single solution that simultaneously optimizes all objectives while fully meeting nutritional requirements is not feasible. Therefore, policymakers and decision-makers can select the most appropriate dietary pattern from the proposed Pareto-optimal solutions according to their specific priorities and policy objectives. The findings of this study provide a practical framework for improving both human nutrition and environmental sustainability. The results suggest that revising certain policies, particularly by increasing support for seafood, fruits, vegetables, and legumes, could substantially reduce pressure on water resources and the environment. In contrast, current pricing policies for some food groups are not necessarily aligned with the long-term conservation of natural resources and environmental sustainability.