The invention relates to a method and a system for altering body mass composition using galvanic vestibular stimulation. A device and method are provided for altering body mass composition in a humansubject by applying galvanic vestibular stimulation (GVS) using electrodes placed in electrical contact with the subject's scalp at a location corresponding to each of the subject's left and right vestibular systems. The current source include a feedback loop for measuring a resistance across the subject's scalp and adjusting a voltage output to maintain a constant current across the subject's scalp. GVS may be applied for a predetermined period of time at regular intervals.