The term hangover is a good one.
After running clean, the carbage reaction is a combination of panic to sequester and critical controls to contain the oxidative spike. It’s basically going into damage control much like an alcohol hangover.
I did it once with a pizza party a couple of months into keto. That event killed pizza for me. Even keto pizza is distasteful now…
It also made me acutely aware that this is how SAD is ruining the lives of so many people who are numb to the damage.
Having said that, there are techniques to introduce high carbs in a controlled manner as part of a weightlifting timed event. It’s like using a dangerous drug under controlled circumstances to achieve a specific short term goal. I have yet to build up the nerve to try it myself…