system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does smoking marijuana make you hungry?

Why does smoking pot give users the "munchies"?
gpt
Your appetite is regulated by a region of the brain called the hypothalamus. When your appetite is supressed, this is due to the hypothalamus ordering the release of a hormone called leptin. 

When you smoke marijuana, it's main active ingredient, tetrahydrocannabinol, binds to certain specific sites called receptors. The main receptor in question is CB1. 

When CB1 is activated, leptin production is reduced, thus increasing your appetite. The main mechanism in which this happens is not yet fully understood.