Vagal nerve stimulation is used to treat epilepsy and depression and more recently has been found to be potentially beneficial for the treatment of obesity. However, the mechanism by which vagal stimulation causes weight loss is unclear. The vagus nerve innervates many intrathoracic and intra-abdominal organs to regulate their function and also contains sensory fibers that monitor intestinal nutrients and volume. Now, Williams et al. have begun to specifically examine the connections between the gut and the brain.