system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: if the human body can go up to a month without food, why does it become so uncomfortable after just a few hours?
gpt
Your body doesn't *want* to go without food, and unlike animals that comfortably go long periods of time without eating (like reptiles), going without food is merely possible, not normal.  Your body starts to show signs of not having eaten way before it completely kills you.  So that's your body telling you "I'd really rather be eating right now: if you can find food, you should."