This Special Issue seeks to contribute to the debate around less resource-intensive sustainable diets demonstrating just how critical a social science perspective is in problematising and enriching the terms of that debate. There is general consensus that the global dietary transition towards westernized diets with high intakes of meat, refined fats, sugar and salt are unhealthy for people and the planet. Healthier and more sustainable diets are widely recognised as necessary to mitigate climate change, reduce the pressure on natural resources including aquatic and terrestrial ecosystems, and lower the global burden of disease. This editorial introduction presents eight articles selected from papers presented at the Conference ‘Sustainable Food Systems <=> Sustainable Diets’ held in October 2019 at The American University of Rome. Representing a diverse range of social science perspectives, the articles demonstrate the complexity in developing a shared understanding of what constitutes healthy and sustainable diets and which are likely to be inherently inter-connected with regenerative agriculture and sustainable food systems. To different degrees the articles also reflect upon policy experiences to date and identify obstacles to the introduction of measures that would facilitate changes in consumption practices. Demonstrating the vital role of critical social analysis in deepening our understanding of the institutional, social, and cultural dimensions of food systems, this Special Issue will fill an important gap in the literature around sustainable diets.