Core Tip: Starch exists in particle form within plant tissues and cells, and digestible starch is typically broken down in the small intestine by α-amylase, glucoamylase, and isomaltase into free glucose, which is then absorbed in the human small intestine. However, not all types of starch can be digested and absorbed in the small intestine. Based on the ability to be completely digested into glucose and the absorption rate in the small intestine, starch is divided into three types: rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS). Resistant starch refers to starch that cannot be digested and absorbed in the small intestine but can reach the colon after 120 minutes and be fermented by the microbial flora in the colon, thereby exerting beneficial physiological effects and is therefore considered a component of dietary fiber.