This thesis explores how ideas of sustainable food consumption are conceptualised and rhetorically contextualised by UK stakeholders such as businesses and NGOs. Drawing on discourse studies, sustainable consumption is considered as a contested field, pertaining to a variety of issues and is instantiated, institutionalised and expressed through varied descriptive, normative and instrumental framings of sustainability and the consumer. Social science studies that hold a critical stance towards consumer agency and the responsibilisation of the consumer are crucial to the underlying theoretical framework of this thesis. However, existing studies concerned with such issues, including those drawing on practice theory, are limited with respect to the rhetorical mobilisation of both the consumer as an agent and consumer agency as a concept. This research is concerned with how the notion of consumer agency is utilised discursively and how the consumer is mobilised as a rhetorical figure in the context of contested framings of sustainability. The thesis empirically explores notions of sustainability and the consumer in expert debates on sustainable food consumption in the UK and investigates their constitution in different temporal and contextual settings. Discourses within the time period 2005-2017 were analysed using three types of data: articles published in The Grocer, the major trade magazine of the UK food industry; interviews with key representatives of retailers, non-profit organisations and consultancies; and policy papers. Firstly, the thesis addresses how notions of food sustainability and related ideas of consumption and production are conceptualised within expert discourses and how those conceptualisations change over time in relation to markets and innovation. Three external discursive strands (premium produce, healthy diets and efficiency) are identified as influencing discursive changes in the period studied. Secondly, it is suggested that three interpretative frames (consumer sovereignty, economic rationality and stewardship) constitute a discursive framework of expert discourses on sustainable food consumption. This framework restricts the ways in which issues can be interpreted and addressed in order to become established as themes within discourses. Thirdly, the findings are positioned with reference to social science debates on consumer agency for sustainability. It is argued that through the interpretative frame of consumer sovereignty, choice constitutes an all-encompassing concept in expert discourse on sustainable consumption. Although consumer choice is attributed little potential for social change, the consumer nevertheless constitutes a central figure of reference in arguments, explanations and legitimisations of other agentsâ conduct. Even where institutional actions could be understood as contrary to consumer choice, for example, choice editing by retailers, such activity is framed as a response to consumer demand for sustainable consumption.