Sustainable diets, which contribute to food security and health are the focus of many policy discussions around the world. The translation of sustainable diets into national and regional dietary guidance is necessary for shifts in population-based behaviour. Food-based dietary guidelines (FBDGs) are one such tool for conveying dietary advice, indeed, the National Food Strategy recommends that 'an updated "reference diet" for the nation' should be developed' which considers both health and sustainability. However, many, including the UK EatWell Guide, have not specifically considered sustainability in their development That said, following the Eatwell Guide has a lower environmental impact than the typical UK diet (2) . Dietitians frequently use the Eatwell Guide to disseminate dietary advice to patients/clients. To understand whether dietitians agree with the inclusion of the latest sustainability principles within the UK FBDGs, all dietitians who are members of the British Dietetic Association (BDA) were invited to participate in an online survey (Google Forms, Menlo Park, California) via e-mail between 25th November and 18th December 2021. The survey assessed attitudes towards sustainability and alternative proteins, including mycoprotein (a protein derived from fungi) within FBDGs, as part of a larger multiple-choice survey, which aimed to identify views on various public health issues. Three questions focused on the EatWell Guide, with five additional questions on sustainability within their professional practice. A total of 188 responses were received. Respondents worked in a wide variety of specialties including 23.9% (n = 45) in weight management, 18.6% (n = 35) in parenteral nutrition and 16.5% (n = 35) in diabetes and pediatrics equally 2.7% (n = 5) reported working within the field of sustainability. A total of 72.3% (n = 136) of dietitians agreed that the EatWell Guide should be updated to better reflect sustainable diets. When asked where they thought meat-alternatives should be represented within FBDGs, 91.5% (n = 172) stated that they should be visually represented among the protein food group and 81.9% (n = 154) agreed that mycoprotein should also be included in this food group pictorially.In conclusion, we have demonstrated that the majority of dietitians surveyed agreed that it is time for an update of the UK FBDGs to incorporate latest sustainability understanding and that protein-based meat-alternatives, including mycoprotein should be visually represented in the EatWell Guide. Further research should be undertaken to validate these findings with a wider sample of healthcare professionals and shared with policymakers. Plant-forward diets, and those containing meat-alternatives, including fungal proteins, are being encouraged by thought-leaders around the world in order to ensure sustainable, healthy food systems that are able to feed a growing global population in a world facing resource constraints and climate change (3,4) .

Mycoprotein is a well-established and sustainably produced, protein-rich, high-fibre, whole food source derived from the fermentation of fungus. The present publication is based on a symposium held during the Nutrition Society Summer Conference 2022 in Sheffield that explored ‘Food for our Future: The Science Behind Sustainable Fungal Proteins’. A growing body of science links mycoprotein consumption with muscle/myofibrillar protein synthesis and improved cardiometabolic (principally lipid) markers. As described at this event, given the accumulating health and sustainability credentials of mycoprotein, there is great scope for fungal-derived mycoprotein to sit more prominently within future, updated food-based dietary guidelines.