The only one I know for sure is alcohol (and I don't even drink!) but its because its quite a common question we get asked as breastfeeding supporters. It hits blood pretty much straight away but clears at a rate of one unit every 2 hours so depending on how much you drink, you should leave at least 4 hours before feeding. Not that I'm saying this is what you were asking about but its the only one I know for sure as there have been studies on it!
I know with Matthew, when I drank coca cola and then fed him, he went completely hyper so it was passed fairly quickly into the milk. Haven't had the same problem with Hannah, so he was maybe more sensitive to caffine levels than she is.
With food, it would have to be in your bloodstream first before it can be passed into the milk, so it takes roughly 8 hours(?) before what you eat is absorbed. Can't remember that far back to A-level biology but I think its something like 8-12 hours. I know if I eat honey chilli chicken for dinner Hannah has awful nappies around lunchtime the next day!
So I suppose the answer is: food will take about 8-12 hours but drink would be almost straight away.
Hope this is useful

Debs