Metabolism of a Vampire, Does Kissing make you puke? Options

[Hamsnibit]

So, my Rigger turned unvoluntarily into a banshee the last session and i decided to read through the books again closesly.
As we know, Banshees have their Dietary Requirement (Metahuman Blood) weakness because the virus reconfigures their digestive system and general physiology, so far so good.

Question is : how far does it go?
Runners Companion states :"vampires and banshees in particular lack most of the symbiotic bacteria that break down food and must subsist entirely on blood."

As a non native english speaker i interprete "food" as anything you have to chew and swallow not included anything you drink. Soups come somewhere in between.

Banshees have to throw up within an hour if they consume any food which isnt blood says the description of the Dietary Requirement Weakness.

So i have two question from this point on:
1. The body of banshees still mainly consists of water : the blood circulates within their veins, they sweat and produce saliva as well as more intimate fluids.
Is the water in their bodies magically created from the blood they consume (which has to be since the amounts are way to small) or do they still have to drink since the text explicitly states food?
2. Which amounts of fluids is enough to make them throw up, IF they cant consume water as well? Are aromas from a chewing gum enough? Is tongue kissing forbidden? Or is it only too much if you drink an entire bottle/cup or whatever of coffee, coke, tea or something?

Banshees are especially prone to alcohol which indicates that drinking isnt really possible anymore, but then still my question stands how much is too much i really have no idea.

My thanks in advance for any good ideas