Little and often, ToGo, little and often. I don't think anybody is recommending a 3 litre drinking session.

However, you ARE in the land of the public toilet, never far from a public convenience. It's good ToGo.

Too much rice and not enough fibre is certain to bring on constipation. You are staying in an area where fresh fruit is difficult to get hold, I had alarm bells ringing about this eventuality before you left Vienna, now they are screaming sirens.