Sustainability nutrition balance: A proof-of-concept metric integrating nutrition and environmental sustainability of foods in the context of whole diets

Food consumption significantly impacts both human and planetary health, necessitating integrative approaches to assessing the nutrition and environmental sustainability of food products. This study introduces the Sustainable Nutrition Balance (SNB) score, an innovative metric that quantifies the environmental footprint of a food product relative to its nutritional contribution, within the context of a nutritionally adequate diet. Unlike traditional nutritional life cycle assessment approaches that assess foods in isolation using predefined nutrient-based functional units, the SNB score captures trade-offs and synergies by embedding foods in a whole-diet framework, using quadratic diet optimization. The SNB method was applied to the average Dutch adult diet using national food consumption data and Dutch-specific environmental footprint and nutrient composition data. Calculated for 351 food products, the SNB score reflects the net change in dietary footprint when a food is added to a nutrient-adequate diet. While meat products generally resulted in positive SNB scores (net increases in footprint), nuts and seeds yielded negative scores by displacing foods with greater footprints. Some foods, like Greek yogurt, had scores near zero, indicating minimal net change due to balanced nutritional and environmental trade-offs. Sensitivity analyses showed that SNB scores are primarily influenced by dietary context and data quality rather than modeling choices. Stakeholder consultations highlighted potential application in product innovation and dietary guidance when SNB is interpreted within nutritionally adequate diets, though concerns remain around interpretability and data demands. While not yet operational at scale, the SNB score provides a promising foundation for advancing integrated metrics that guide sustainable nutrition strategies. • Innovative metric combining nutrition and environmental footprint with optimization • SNB score quantifies net footprint of a product in a nutritionally adequate diet • Meat showed highest (high net footprint), nuts and seeds lowest, average SNB scores • Metric is intentionally diet-sensitive, but highly dependent on data quality • Future research should improve interpretation and communication of integrated metrics