system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How the body knows when to start digesting food and when the food exits the stomach?
gpt
When you eat something, it goes in your stomach. In your stomach, the acids eat away at the food, but not all of your food. Then it gets thrown into your small intestine, the intestines have little things kinda like an antennae which touch the food and go, "We got food in here from the stomach, bring the chisels and the hammers". The stuff that came down now breaks up the food in your intestine. Then tentacle like things grab onto the smashed up food and eat it with smaller tentacle things. What doesn't get eaten goes into your large intestine and water gets taken out, and little bacteria eat the food and poop out other stuff we need. Then we poop out the stuff we don't need. And if you eat a lot of beets, it turns red. So don't eat a lot of beats. 


TL;DR eat food, antennae tell body to send stuff to break food, food gets broken up, tentacles eat food, we poop it out.