I DRINK more than a pot of coffee a day and vape at least 30 ML of 6mg nic a day out of a sub ohm mod so it’s alot of vapor and I do OMAD and I’ve been doing it for a long while and I’m telling you any benefits I’ve ever heard of from fasting I’ve experienced them all. I don’t think it makes a big difference vaping and I know forsure coffee and teas with out cream and sugar don’t because I did that first before vaping while fasting and I’m feeling great and looking even better
One important thing is that different people have insulinic responses to different things at different levels. Someone posted a link one of these days that smells can cause insulin response for some.
Non-sweetened teas/coffee are fine for most people.