I'm drinking a cup of crutch right this minute.
If you don't put anything in it, and it's calorie free, then how could it be wrong
in the IF-ing scheme of things?
I *do* put 15g of heavy cream in mine, so technically I'm not really "fasting"
until my 3pm time - but after I drop my kids at school I'll walk 6 or more miles
or go to the gym, so, to myself about IF, I say, "bite me and my 50 calories".
Coffee and other zero calorie beverages are fine to help you through, just don't
go balls out on pots and pots of coffee......