How long does a bad reaction take to start?

[LilyR]

If you eat something that bothers you, something maybe you didn't even know would bother you (could have had a corn ingredient in it, or some sort of additive), how long before you start feeling discomfort?  Would it be possible to have something in the morning, but not have it start bothering you until right after dinner?  

I was starting to feel a little better (stomach wise) and getting the hang of things, but every now and then I seem to eat something (with no gluten) that bothers me.  An example - one morning I had Dunkin Donuts hazelnut coffee (the kind you buy in the store and go home and brew yourself, not one you get right at DD with the flavor syrup added). The ingredients were coffee, and natural and artificial flavorings.  I took a chance and had some very early in the morning, and  I was fine all day.  I made soup that night for dinner.  I put in a few gluten-free chicken bouillon cubes.  Immediately after dinner I got hard bloat and discomfort.  I assumed it had to be the chicken bouillon cubes since that is what I had just ingested.  But I had them once before and don't recall getting bad.   So all I could think of was some sort of delayed reaction to that morning's coffee?  Has that ever happened to any of you?  I am actually hoping it was just the bouillon because I can easily do without that.  But it sure was nice to have a flavored coffee.  I am guessing I wait until my stomach has been doing well again for a while, and then try the coffee again, and see if it bothers me or not?  And then do the same with the chicken bouillon too at some point?  Is that what you all do? To try to find out what item it was that bothered you?  I guess from now on I need to only add a new food or drink if I know every other single thing I eat that day and night is something I know for sure I eat all the time and does not bother me.  

It is getting confusing.  I usually make homemade mashed potato, but did get some instant and had it the other night.  I also had a gluten-free turkey burger with it that I've been eating several times the past few months, and it seems fine.  But I had the instant mashed potato with it one night, and had some bloat and discomfort.  It sure is trial and error, isn't it?  Sometimes I eat something with a corn ingredient in and and seem okay. Other times I have something else with corn in it and it bothers me.  I am guessing I should just now stay away from all corn, period, and not that the chance.