Food systems contribute greatly to global climate change due to their substantial contributions to greenhouse gas emissions, water use, and resource allocation. In addition, current food systems fail to deliver healthy and sustainable foods for all, with obesity as well as undernourishment remaining a pertinent global issue. Mounting pressures such as population growth and urbanisation urge rapid and transformational adaptations in food systems to sustainably feed a growing population. Sustainable diets have been promoted as a potential climate change mitigation strategy, and are characterized by high plant based foods and reduced animal-sourced and processed foods. While the evidence base on the potential health and environmental impacts of shifts towards sustainable diets has been growing rapidly over the past decade, there has been no recent synthesis of the evidence surrounding the health and climate mitigation benefits of sustainable consumption patterns. This systematic review will synthesize the evidence of both empirical and modelling studies assessing the direct health outcomes (such as all-cause mortality and body mass index) as well as environmental impacts (greenhouse gas emissions, land use, water use etc.) of shifts towards sustainable diets. Eight literature databases will be searched to identify studies published between 1999-2019 that report both health and environmental outcomes of sustainable diets. Evidence will be mapped and subsequently analysed based on the comparability of results and reported outcomes.