system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why when I go to sleep with a FULL stomach (ie Thanksgiving Night) I wake up STARVING! However, when I go to sleep with an empty stomach I wake up with a normal appetite or none at all?
gpt
The guys talking about insulin are closest. When you eat, your blood sugar rises. Insulin is released to force the sugar out of the blood and into storage (into fat cells or to restore muscle glycogen). Your body tries to keep normal insulin range of about 90-110. After your body is done getting the sugar out of your blood, you actually dip below the 90 end for a little bit. This usually results in you being hungry again. In regards to Thanksgiving, you were processing food for an extended period of time, and you probably woke up in the low part of the insulin dip.

This is also why eating simple carbs (bread, fruit, desserts, etc) keep you hungry: because you spike and then dip again. Adding in some healthy fats will slow digestion some and keep your insulin in a smoother curve instead of a violent up/down curve.