system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does my stomach growl?

What causes the noises it makes when I'm hungry and after I eat?
gpt
Stomach growling is the sound of peristalsis, the process of the muscles in your digestive system doing its thing to move food through you. Normally you can't hear it because the sound is muffled by food in your digestive system. But when you're hungry, the body triggers peristalsis to remind you to eat. You can hear it at this point because there's nothing within your digestive system to muffle the sound.