At the crossroads: new paradigms of food security, public health nutrition and school food.

Public health nutrition sits at the nexus of a global crisis in food, environmental and health systems that has generated - along with numerous other problems - an urgent and changing problem of food insecurity. The 'new' food insecurity, however, is different from the old: it is bimodal, encompassing issues of both under- and over-consumption, hunger and obesity, quantity and quality; it has assumed a decidedly urban dimension; and it implicates rich and poor countries alike. The complexity of the expressions of this challenge requires new approaches to public health nutrition and food policy that privilege systemic, structural and environmental factors over individual and mechanistic ones. In this context, the current paper argues that school food systems rise with buoyant potential as promising intervention sites: they are poised to address both modes of the food security crisis; integrate systemic, structural and environmental with behavioural approaches; and comprise far-reaching, system-wide efforts that influence the wider functioning of the food system. Based on a discussion of Bogotá and other pioneering policies that explicitly aim to create a broader food system with long-term foundations for good public health and food security, the paper suggests a new research and action agenda that gives special attention to school food in urban contexts.