The main nutrients available to the bacteria of the human gut are glycans derived from both dietary and host sources and fermentation of these complex macromolecules contributes significantly to host health and nutrition. Bacteroides are one of the dominant genera in the gut and are able to utilise a large number of different glycans, providing community resilience in this dynamic and competitive niche. The ability to degrade glycans is encoded by polysaccharide utilisation loci (PULs) which encode a suite of cell envelope associated enzymes, glycan binding proteins, TonB-dependent transporters and regulators each tuned to a specific glycan, with many Bacteroides spp. encoding >100 PULs. In this talk I will discuss some of our latest findings that provide significant insight into how Bacteroides spp are able to break down the host glycan heparan sulfate, and the complex glycans of the fungal cell wall and how these findings aid our understanding of competition and survival in the gut.