Food systems must operate within environmental constraints to avoid disastrous consequences for the biosphere. Such constraints must also take into account nutritional quality and health outcomes. Given the intrinsic relationships between the environmental sciences and nutritional sciences, it is imperative that public health embraces environmental nutrition as the new frontier of research and practice and begins a concerted focus on the new discipline of environmental nutrition, which seeks to comprehensively address the sustainability of food systems. We provide an overview to justify our proposition, outline a research and practice agenda for environmental nutrition, and explore how the complex relationships within food systems that affect public health could be better understood through the environmental nutrition model.