The world is currently facing two interconnected and severe crises: widespread malnutrition and environmental degradation. Food systems are central to both issues, as they are responsible for a significant portion of greenhouse gas emissions, natural resource depletion, and environmental damage, while simultaneously feeding billions of people. Diets are a crucial link between human and planetary health and have been identified as a key lever to address both the climate and malnutrition crises. However, there are inherent trade-offs between nutritional and environmental goals, making it difficult to find solutions that simultaneously improve both outcomes. This paper introduces nutritional Life Cycle Assessment (nLCA) as an evidence-based tool to guide policy, programmatic, and industry decision-making, and demonstrates how nLCA can provide actionable, context-specific insights that help reconcile (often competing) nutritional and environmental priorities.