'Alternative protein' is a phrase used to describe either specific protein sources (such as microbial mycoprotein) high-protein foods which can be considered alternatives for animal proteins and animal source foods. The term is most typically used of proposed novel foods, but in the context of discussions of radical changes to the food system to achieve greater sustainability is also used of traditional foods whose consumption could be increased. Some foods commonly referred to by the term alternative proteins are insects, ultra-processed plant-based meat substitutes, cultured meat, single-cell proteins, and minimally processed legumes.