Environmental and societal implications of transitioning to sustainable diets

The global food system plays a crucial role in shaping societal and environmental futures, with dietary shifts having broad implications across multiple sectors. While plant-based and non-ruminant proteins are gaining popularity in wealthier nations, regional adoption of sustainable diets remains uncertain and highly variable. Here, we explore the benefits of increasing plant-based protein intake or reducing ruminant livestock consumption across global and regional scenarios. Using an Integrated Assessment Model, we find that sustainable diet transitions enhance regional protein and fat intake, improve dietary energy adequacy, and reduce greenhouse gas emissions, air pollution-related mortality, water scarcity, and food costs. These changes also support re/afforestation and biodiversity gains, though some regions may face trade-offs. Notably, regional efforts yield faster benefits compared to uniform global targets. Our results emphasize the need for effective social policies to promote a shift toward plant-based and low-ruminant diets, demonstrating their nutritional and environmental advantages.