Reducing disease burden through sustainable diets: a modeling approach for national food-based dietary guidelines.

Introduction: Shifting to sustainable dietary patterns is essential for improving human and planetary health. Current dietary habits substantially contribute to non-communicable diseases and environmental impacts, particularly due to high consumption of animal-based foods. Food-based dietary guidelines (FBDGs) that integrate nutritional, health, and environmental dimensions are therefore increasingly important. While global frameworks highlight the need for sustainable diets, national guidelines must reflect cultural and regional contexts to ensure feasibility and acceptance. Mathematical optimization has emerged as a promising approach to develop such guidelines. Methods: This study aimed to update the Austrian FBDGs using mathematical optimization, incorporating nutritional adequacy, burden of disease expressed as disability-adjusted life years (DALYs), cultural acceptability, greenhouse gas emissions (GHGE), and land use (LU). Linear programming was applied to identify dietary patterns that meet nutritional requirements, minimize environmental and health impacts, and remain close to observed Austrian dietary intake. The optimized model outputs formed the scientific foundation for translating results into consumer-oriented national dietary guidelines. Results: The optimized diet met all nutrient recommendations and macronutrient distribution ranges. The resulting FBDGs emphasize higher intakes of plant-based foods, particularly vegetables, fruits, grains, and legumes, alongside substantially lower amounts of animal-based products. Meat intake should not exceed 300 g per week, while legumes are recommended at least three times per week. Compared with the current Austrian diet, the optimized dietary pattern suggests a potential reduction in diet-related health burden and environmental impacts (DALYs -43%, GHGE -58%, LU -61%), highlighting its potential to improve public health and reduce environmental pressures. Discussion: The updated Austrian FBDGs provide clear, quantitative recommendations that simultaneously ensure nutritional adequacy, reduce disease burden, and support environmental sustainability. As current meat consumption substantially exceeds recommendations, gradual dietary shifts are essential. Increasing legumes and minimally processed legume-based products can facilitate this transition. Effective implementation will require broad communication efforts and supportive food environments to the enable adoption of healthier and more sustainable dietary patterns.