Optimizing sustainable, affordable and healthy diets and estimating the impact of plant-based substitutes to milk and meat: A case study in Spain

The global food system is failing to appropriately nourish the population and has been identified as a driving force for environmental degradation. Changing current diets to healthier and more sustainable ones is key to decrease the incidence of non-communicable diseases and force changes at the production stage that will release environmental pressure. The determination of such diets is a challenge since it should be context specific, culturally acceptable, affordable, nutritionally adequate, and environmentally friendly. Through multiobjective optimization we aimed to determine a sustainable and healthy diet(SHD) in Spain with the minimum cost and environmental impact (assessed through GHGe, land use and blue-water use) that deviate the least from current consumption. Additionally, this research also compares the optimised diet with the Spanish food-based dietary guidelines(FBDG), and explores the potential benefits of reducing animal meat and milk while replacing them with plant-based alternatives. Compared to current consumption, a SHD in Spain can be more nutritious and reduce cost, GHGe, land and blue-water use by 32%, 46%, 27%, and 41%, respectively. The Spanish intake displayed the worst nutritional assessment and the highest values for GHGe and land use. The Spanish FBDG showed the highest cost and blue-water usage. Further analysis revealed that plant-based meat alternatives are not necessary to achieve a nutritionally adequate diet at the minimum cost and environmental impact. Shifting to fortified plant-based milk alternatives may add additional environmental benefits. This work emphasizes the potentiality of using optimization to determine a SHD and identifies important gaps to be fulfilled in future research.

Automated summary

The global food system is failing to nourish the population and causing environmental degradation. Changing diets to healthier and more sustainable ones is crucial. Through optimization, a sustainable and healthy diet (SHD) in Spain with the minimum cost and environmental impact has been determined, showing better nutrition, reduced cost, GHGe, land use, and blue-water use compared to current consumption. This study also highlights the potential benefits of reducing animal meat and milk and replacing them with plant-based alternatives.