The first 1,000 days of life—from conception to a child’s second birthday—is a critical window of opportunity for optimizing nutritional, health, and development outcomes of current and future generations. As part of its core objective to expand the evidence base on addressing malnutrition, FANTA and some of its research partners—the International Food Policy Research Institute, the University of California, Davis (in collaboration with ICDDR,B), and the University of Tampere (in collaboration with the University of Malawi College of Medicine)—conducted four major studies in Bangladesh, Burundi, Guatemala, and Malawi examining interventions aimed at preventing undernutrition during that period. The studies yielded important lessons learned, programmatic implications, and recommendations on implementing the preventing malnutrition in children under 2 approach and on using micronutrient powders and small-quantity lipid-based nutrient supplements to improve nutritional outcomes among pregnant women and children. While more research is needed, it is hoped that these studies will contribute to effective nutrition-specific and nutrition-sensitive policies and programs that reduce malnutrition.