There has been a lot of interest in neuroeconomics lately, focusing on decision-making and the brain. But there are also a lot of neurons in the gut, which raises the possibility of a part of neuroeconomics that might be called gastroeconomics.
This Scientific American article brought all this to mind:
Microbes Manipulate Your Mind: Bacteria in your gut may be influencing your thoughts and moods
(This shouldn't be confused with the gastroeconomics associated with the market for gastroenterologists:)