A body impedance analysis, BIA, system comprising a host and an accessory device connectable to the host device via a data cable. A first and a second electrode are arranged on an outside of the accessory device and a third and a fourth electrode are arranged on an outside of the host device. A BIA circuitry is connected to the third and the fourth electrode and connectable to the first and the second electrode via the data cable. The BIA circuitry is configured to drive an alternating current through the body via the first and the third electrode, to sense a voltage indicative of a body impedance via the second and the fourth electrode and to determine the body impedance depending on the sensed voltage.