Food and sustainability are intrinsically linked, yet the majority of food education in the Republic of Ireland focuses solely on health, and this form of education fails to address the complicated nature of the modern food system and its negative impact on biodiversity. Using the capabilities approach as a framework, this article argues that the purpose of food education should be to provide students with the ability to lead a flourishing life. The capabilities approach is used to evaluate the creation and implementation of a two-year programme entitled Green-Schools Food and Biodiversity Theme. The theme was designed by the researcher using an action research methodology with Green-Schools staff, and in direct consultation with the children and teachers in eight participating pilot schools. The theme presents a broad food-based subject. This article reflects on the process and suggests that students involved in the programme were equipped with an increased ability to make critical decisions about food, as well as an increased awareness of sustainability and biodiversity. The potential exists for the theme to be used as an exemplar for embedding a new type of food education into Irish schools, one where the impact of food on sustainability and biodiversity is better understood.