Food waste represents a growing global crisis equivalent to ∼1.3 billion tonnes/year. This review provides an overview of the potential of food waste as a carbon source for microbial upcycling using anaerobic digestion (AD) for bioenergy coupled with single cell protein (SCP) production. We estimate biogas potential from food waste to be sufficient to generate electricity for 26,500 UK households. Additionally, the concept of mixed communities is considered as an alternative to traditional pure culture fermentation for SCP, and a literature review of 82 genera for SCP from food waste and biogas is presented. Improvements in the understanding of microbial community structure and function are still required to improve reactor performance. Future research should focus on providing insight of the AD microbiome, considering the role of syntrophic relationships in reactor stability, alongside integrated whole systems sustainability assessment of microbial upcycling technologies.