This paper presents the Smart Grocery Shopping system (GROCAFAST), a system for optimizing the grocery shopping experience and improving efficiency for shoppers. The GROCAFAST system consists of a mobile app and a server component. The mobile app allows shoppers to create, manage, and update grocery lists while providing store navigation assistance. The server component processes data, generates optimized route maps, maintains an inventory database, and facilitates the online chat room. Unlike existing grocery shopping systems, GROCAFAST is cost-effective as it does not rely on any extra infrastructure and reduces both shopping time and walking steps. GROCAFAST utilizes Dijkstra's algorithm to efficiently guide shoppers through the store, minimizing the time needed to visit all aisles containing their desired items. The user-friendly interface and time-saving features make grocery shopping more efficient and enjoyable. The evaluation results demonstrate that GROCAFAST reduces the total shopping time by 67.6% when compared to a traditional approach that mimics the way shoppers visit a grocery store, browse aisles, and select items. It also reduces the walking steps by 59%.