system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why can I drink water and eat salty food but not drink saltwater?

Always thought about this but never gotten any answer.
gpt
You can drink salt water, it just has a LOT more salt than you think.  A liter of seawater has around 35g of salt.  That's about 5 or 6 teaspoons of salt.  

Seawater is about 3 times as salty as the human body, so if you drank a cup of seawater, you'd want to drink 2 more cups of freshwater to balance everything.