In addressing the complex challenge of ensuring food and nutrition security for a growing and rapidly urbanizing global population, we need appropriate tools for developing policies that are not only effective but sustainable and socially just. In this chapter we outline a human ecological approach that can be used by policy thinkers, managers, governments, and others to support the analysis, critique, and design of policies, programs, and services to manage problems in complex human-environment systems. At its core, the approach involves consideration of the interactions and feedbacks between the following main components of the given system: the environment; human health; policies/institutions; and cultural paradigms. While the general approach can be applied to any human-environment system, here we present the framework through the example of food and nutrition security, in particular contrasting two examples of how different paradigms can influence policy and management approaches and in turn give rise to different systems and different outcomes for both human and environmental well-being.