Meat holds powerful positions in Western food cultures, which have been propelled to diverse geographies across the globe throughout contemporary human history. Agro-industrialisation of food systems has led to mass production of animals for mass consumption of meat, with deeply unequal access. Meat production and eating is expected to increase globally; however, keeping, feeding, watering, medicating, transporting and slaughtering billions of animals for meat already occurs at scales which significantly contribute to human activities rapidly unravelling the tapestries of life. How to change, or transform meat and food systems towards sustainability therefore attract attention within research, in civil society, in politics and public debates. The aim of this thesis is to analyse whether ideas of ‘less but better’ seem to be working to alter the status quo of Western meat through studying forms of ‘less but better’ as theories of change. To do this, the thesis and five papers analyses two modes of ‘less but better’ meat present within practice and research today: as consumer-oriented where people are to shop, cook, eat or farm ‘less but better’ meat (Papers 1-3), and as projections of ‘less and better’ meat futures within resource or sustainability boundaries (Paper 4). Paper 1 provides empirical evidence of scientific interpretations and uses of ‘less but better’, conceptual interactions between ‘less’ and ‘better’, and prevalent meanings of more sustainable, ‘better’ meat as organic, free-range, local, and small-scale. Paper 2 and 3 provide empirical evidence of the sustainability implications of change towards ‘less but better’ meat in farming and eating in Sweden and Finland. Paper 4 explores ‘less and better’ through future meat scenarios thinking with biodiversity-based sustainability limits to ruminant animals. The thesis investigates mechanisms and functions of the two modes of ‘less but better’, as well as their embedded notions of change and understandings of food systems sustainability. Lastly, Paper 5 provides an alternative way of approaching change of meat for food systems sustainability, and discusses how unmaking meat could be a way to recentre the notion of strong coupling between ‘less’ and ‘better’ for transformative change. This thesis contributes to sustainability science and practice by studying ‘less but better’ as theories of change, and by bringing together diverse bodies of knowledges on sustainability problems and solutions to meat. Finally, the thesis captures and makes sense of diverse onto-epistemological underpinnings, while navigating an early career researcher journey into complex and strongly political realms of enquiry.