The Sustainable Development Goals (SDGs) are intricately linked to food systems. Addressing challenges in food systems is key to meeting the SDGs in Africa and South Asia, where undernutrition and micronutrient deficiencies persist, alongside increased nutrition transition, overweight and obesity, and related chronic diseases. Suboptimal diets are a key risk factor for mortality and 3 billion people cannot afford a healthy diet; in addition, food systems are not prioritizing environmental sustainability. Optimizing food systems and increasing agricultural productivity beyond calories, to nutrient-rich vegetables and fruits, legumes, and livestock, and sustainable fishing, are required. Strengthening of research around food systems—on pathways, value chains, and development and validation of metrics of diet quality—is required. The development of new technology in crop management and pest control and addressing natural resource degradation is key. Engaging with the public and private sectors, outreach to donors and policymakers, and strengthening cross-disciplinary collaborations are imperative to improving food systems.