Plant-based foods contain a variety of dietary fibres. These special oligo- and polysaccharides are fermented by the numerous bacterial strains in the gut collectively known as the microbiome. Scientific studies have shown that dietary fibre exhibits different properties depending on the plant from which it was isolated, with each type serving as a source of food for specific bacterial species, e.g. Bacteroidetes, Firmicutes, Lactobacilli or Bifidobacteria. Oligosaccharides (such as glucomannan, pectins and XOS) are metabolised relatively quickly due to their short-chain structure, while long-chain and branched-chain polysaccharides (such as psyllium husks, acacia fibre, beta-glucans and olive pomace) are metabolised much more slowly. Focusing on the intake of a rich variety of dietary fibre therefore seems to be the key.