system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do I sweat when I eat something spicy? What use is this?
gpt
There's no "use" for it. It's just your body's reaction to the irritants in the spicy food being interpreted as heat. 

Chilies taste hot because the chemical in them, capsaicin, triggers your mouth's heat-detecting nerves. They say to your brain "Wow, it's really hot", so your brain tells your skin to start pumping out sweat in order to cool you down.