In everyday life, sugars are usually experienced as sweet tasting substances. In the domain of sciences, sugars are the third pillar of life next to DNA and proteins. The diverse roles of sugars that make them key elements for functions, structures and interactions in nature are discussed in this video. Bernard Henrissat is Research Director of the Glycogenomics group at the Architecture et Fonction des Macromolécules Biologiques (AFMB), a research centre that belongs to the Centre National de la Recherche Scientifique (CNRS) and the Université Aix-Marseille, France. His research group develops the carbohydrate-active enzymes database CAZy, a dedicated family classification system that correlates with the structure and molecular mechanism of carbohydrate-active enzymes.