Changes in our climate and physical environments are having profound effects on all aspects of human existence, and the ability to develop sustainable and resilient food systems is critical not just to the environment but to all aspects of human health. The Pediatric Growth and Nutrition Branch (PGNB) of theEunice Kennedy ShriverNational Institute of Child Health and Human Development of the US National Institutes of Health has adopted a new paradigm to undergird the study of nutrition that recognizes the complex and reciprocal nature of the relationships between nutrition and health outcomes. This conceptual framework, termed the “nutritional ecology,” views humans as complex biological systems interacting with both their internal and external environments. Herein, we focus on: (i) the reciprocal relationship between climate and environmental changes and food systems and their impact on food/nutrition security and health; and (ii) how PGNB is utilizing the “nutritional ecology” framework to support science addressing the interactions among health, nutrition, food systems, climate, and the environment.