system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do you get so hungry when you are high?

I was thinking, what makes you so hungry when you are high?
gpt
In your body you have an Endocannabinoid system which has a role in appetite, pain-sensation, mood, and memory. 

It's suggested that THC the psycoactive compound in cannabis activates a receptor called CB1 which directly increases appetite when fired.