Though I am not Muslim, I had been respecting my colleagues and not eating or drinking while on campus and at work. But I gave that up working on Saturday. I call it 'not eating' instead of fasting just to keep things straight in my own mind.
Generally speaking, I have been weakened by the reintroduction of whatever clever little bugs I find myself surrounded by here in Kabul. I am indeed weak, but not sick. Meaning that I don't need gut medicines. It takes about two weeks to adjust a bit better before I find myself semi-normed. No Westerner that I know of ever feels normal while here.
We do our best.