system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is it that I've lost weight by the time I have awaken in the morming, yet I haven't gone to the washroom? Where did all of the weight go?

I weighed myself before bed and was 170lbs and in the morning just when I got up I was 165. I did this before a trip to the washroom.  So where exactly did a whole 4-5 lbs go while I was sleeping.
gpt
Magic! No, not really.

The short answer: Into the air.

Okay, you know you inhale in oxygen which is O2 right? And exhale carbon dioxide which is CO2. Ever wonder where that carbon atoms comes from? Done.