I wish the first time around with Masyn that in the hospital someone had told me that LO's can be intolerant to milk, and that caffiene can affect them. Yikes, she was in such pain and here I was tossing back milk, cheese, coffee....whoops! Glad the second time around I was smart enough to cut back on dairy ahead of time just in case.
As for foods with hidden dairy...hot dogs, sandwich meat, french fries (McDonald's are dairy free now). Then there are the other names for dairy, which you need to be well versed in to read labels. Also, that ingredients in things change all the time, so you have to remember to read them every time you buy something.
Thank goodness soy was okay for us, that one is even harder as it seems to be in everything!!!