It is well known that food has a considerable environmental impact. Less attention has been given to mapping and analysing the emergence of policy responses. This paper contributes to that process. It summarises emerging policy development on nutrition and sustainability, and explores difficulties in their integration. The paper describes some policy thinking at national, European and international levels of governance. It points to the existence of particular policy hotspots such as meat and dairy, sustainable diets and waste. Understanding the environmental impact of food systems challenges nutrition science to draw upon traditions of thinking which have recently been fragmented. These perspectives (life sciences, social and environmental) are all required if policy engagement and clarification is to occur. Sustainability issues offer opportunities for nutrition science and scientists to play a more central role in the policy analysis of future food systems. The task of revising current nutrition policy advice to become sustainable diet advice needs to begin at national and international levels.