Resistant starch type 3 (RS-3) is starch found in cooked and cooled products such as pasta, rice or potatoes. During cooling, a specific part of the starch molecules tends to recrystallize, making them more difficult to be digested in the small intestine. The undigested starch travels to the colon, where it serves as feed for gut microbiota. The gut microbiota ferment the resistant starch to health-beneficial metabolites, thereby conferring a health-benefit for the host. In this research, we aim to understand how to design RS-3 ingredients that are highly resistant to digestion in the small intestine, while simultaneously being fermentable by gut microbiota. Such highly resistant RS-3 ingredients are dietary fibres that might promote a healthy gut by stimulating health-beneficial gut microbiota and healthy metabolite production.