It has long been thought that the brain controls every process in your body, and to an extent, this is true. On the other hand, there's another side to the story that suggests some parts of the body don't require the brain at all.
There's a second part of your body that can control certain functions, and it's known as the Enteric Nervous System. It can control your entire digestive system all the way from your esophagus to your anus, and it doesn't even require the brain to function.
This nervous system sends 80-90% of your body's gut signals to the brain, rather than vice versa, suggesting there's some form of additional "thinking" activity going on somewhere in your gut.
Although you may not have two brains, you may very well have two different systems controlling functions in your body. The Enteric Nervous System probably played a big role in the early evolved forms of humans to ensuring we only ate the things that were safe for us to eat and that we enjoyed eating.
It has also been found that the microbes in your gut can influence your eating habits by releasing dopamine, a hormone that makes you feel food in certain situations.
Perhaps the expression, "think with your stomach" has some truth behind it after all.
