Wireless Body Area Networks (WBANs) are one of the special branches of Wireless Sensor Networks (WSNs) that attract attention in various disciplines such as health, engineering, biology, and computers. Also, WBANs are an important research area that can contribute to human life and health in many ways. The Software-Defined Networking (SDN) approach is a solution that can make simpler, flexible, manageable, and more efficient the heterogeneous and complex network structures, such as WBANs. In the Software-Defined WBAN (SD-WBAN) architecture, it is of great importance to extend the network lifetime due to the limited energy of the sensor nodes and the routing process is one of the most important energy consumption processes of SD-WBANs. For an effective and efficient routing approach, service quality requirement parameters, for example, throughput, energy efficiency, end-to-end delay, and packet transmission rates need to be considered. In this study, a new energy-efficient and SDN-enabled routing algorithm (ESR-W) has been developed with the use of the Fuzzy-based Dijkstra technique. So, the most appropriate route determination is performed with a central and reactive (on-demand) approach among many SD-WBAN users. SNR, battery level and hop count metrics are used for routing decisions. In order to compare ESR-W with existing protocols AODV and SDNRouting, extensive scenarios and simulations have been performed in the Riverbed Modeler simulation software. According to the results, ESR-W has been observed very successful compared to other protocols in terms of throughput, end-to-end delay, packet transmission rate, and energy consumption.