system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do you feel so excruciatingly bad, sometimes even hours, before you puke?

Currently, I've got my head in the throne. Been here for 3 hours, happy I remembered my phone. I guess a good bonus question is, what would be safe to eat when I'm done sticking my head where I poop?
gpt
It’s because your body recognizes there’s something in your stomach that could be bad for the whole system. So it’s stopped it from moving through your digestive tract. 

Your stomach has two sphincters and when you have food poisoning the pyloric splinter (bottom one) of your stomach tightens to stop the passing of contaminated food(chyme) to your intestines. Which is what causes the feeling of knots.