The objective of this study was to explore the synergies between nutritionally healthy and ecologically sustainable diets. The aim was to explore the possibilities for future integrated dietary guidelines that support consumers to make informed dietary choices based on both ecological and nutritional values. We developed a score system for health and sustainability. Subsequently, we tested six different diets: current average Dutch, official ’recommended’ Dutch, semi-vegetarian, vegetarian, vegan and Mediterranean. For the sustainability rating, we used the Life Cycle Assessment, measuring the impacts on greenhouse gas emissions (GHG) and land use (LU). For the health rating, we used ten nutritional indicators. By comparing the overall scores we found that the consumption of meat, dairy products, extras, such as snacks, sweets, pastries, and beverages, in that order, are largely responsible for low sustainability scores. Simultaneously, these food groups contribute to low health scores. We developed a matrix that illustrates that the health and sustainability scores of all six diets go largely hand in hand. Fig. 1 provides a visualisation of the position of the six diets in the full health and sustainability spectrum. This matrix with scores can be considered a first step in the development of a tool to measure both sustainability and health issues of specific food patterns. In selecting the diets, we examined two directions: health focus diets and the animal protein reduction diets. The Mediterranean diet is generally the health focus option with a high sustainability score. We conclude that guidelines oriented in between the two directions (i.e., semi- and pesco-vegetarian) are the option with the optimal synergy between health and sustainability.
