

Corn sugar is made up of a pretty large amount of glucose, so eating corn is like eating one of the shock tabs. Which is also a good way to confirm that it’s glucose; rice, beans, and chocolate cake all contain pretty small amounts of just glucose, the other sugars need time to break down.
With equal (ie unlimited) access to both Ketamine is going to be a lot faster. They will both cause psychosis eventually, and both cause irreversible harm to major organs (kidneys/bladder and pancreas) after sustained use, but alcohol takes between 10-20 years of solid abuse before it starts to do serious damage, Ketamine only takes months to a few years.