This issue of Annales Nestlé highlights the fundamental importance of complementary feeding in shaping long-term health outcomes. Leading experts present evidence on how the timing, composition, and context of introducing solid foods influence risks for obesity and allergy, shape food preferences, and establish lifelong eating habits. The articles examine strategies for obesity prevention, harmonized global approaches to food allergy prevention, the biological and experiential factors that drive food acceptance, and optimal feeding practices for healthy growth. Together, these insights provide