I have an appointment for my first anti Covid-19 inoculation tomorrow, Wife insists hat I must fast for 24 hours before and after the injection and likewise abstain from alcohol, tea and coffee for 48 hours before and after. She offers no reason for it other than "Everybody Knows that ". Alcohol I understand. but. I cannot see any justification for a ban on te.a and coffee.

Can any medical expert educate me ?

Funnily I was told the opposite about the food  ie: better to have sustenance, and even eat something before your shot. The coffee idea is because of the caffeine, and I could see the sense in that, so abstained for a day or so before and after.

No problem eating and drinking ,although i did hear not to drink alcohol or coffee before the shot . apart from that eat drink and be merry 

Eat normally.  Don't fast.

Drink less alcohol than you would normally drink.  If you can do it don't drink any alcohol. If your body doesn't tolerate abstinence drink less than usual. 

Coffee is no problem. Don't drink too much of it.

 

I do have a medical background.

 

Latest information from She who must be obeyed;a policeman in in Mae Rim has died of a heart attack two days after getting his jag and he drank coffee. She heard that in the market.