I can only speak from my own experience ... so if I would have beef after 3 days I would get uncontrollable diarrhea . Never mind beef now,just an example,it could be anything ...,what I am trying to say is that, if you ate something that you do not eat on regular bases and after 2-3 days you get diarrhea, than your stomach does not like that specific food . So start making mental or written diary of what you eat and drink and make connection .Like if you go to restaurant for lunch on Saturday and on Tuesday you are having diarrhea than your problem might be the lunch that you had on Saturday . Not saying that restaurant served bad food ,but that specific item that you ordered does not agree with you. Once again ,I am talking from my personal experience ...for me it takes 2-3 days for problems to start after I ate something that my gut does not like .For you it might be 1-2 days..or 4 days . It does not happen to me any more because I figured out some time ago what foods creates me stomach problems,so I avoid those foods.