Lifespan extension has not prevented age-related decline. We propose that diet acts as a molecular modulator of aging, influencing inflammation, the microbiome, and systemic resilience. Biological age markers and AI-powered multi-omics reveal actionable dietary targets, including food-derived signals and Nutrition Dark Matter. We highlight precision nutrition and the EIT Food Healthy Aging Think & Do Tank as pathways to align science, policy, and practice for healthy aging.