An obesity treatment system has a first treatment region sized and configured for deployment in a duodenum and a second treatment region sized and configured for deployment in a stomach. The first and second treatment regions are spaced apart a distance sized and configured to permit simultaneous deployment of the first treatment region in the duodenum and deployment of the second treatment region in the stomach. The first and second treatment regions each carry at least one electrode, which can deliver energy to ablate tissue in and the duodenum.