The invention provides methods and devices for ablation of stomach tissue to treat obesity. For example, the invention may involve ablation of mucosal tissue to inhibit ghrelin production, recognized as a root cause of increased appetite. The invention alternatively may involve ablation of sub-mucosal tissue to alter myoelectric activity and thereby induce gastroparesis. As a further alternative, gastric muscle tissue, vagal nerves within the stomach or the pyloric region may be ablated to alter stomach function and thereby induce gastroparesis.