I'm getting my reversal due to my history of obstructions, so getting shouldn't prevent you from getting rid of the bag. I'm generally sore for a few days afterwards and for the first 24-48 hours following my output is basically water.
Like UnXmas above I've got a list of things that I need to avoid, oatmeal and potatoes are the ones high on the list for me (although I'm totally fine with potato chips).
If you know how long it takes for food to pass through your system, it can be fairly easy to track down the culprit, make a list of everything you ate in the day before the obstruction, if it happens again do the same thing and look for similarities. For me it took about 5-6 hours for a meal to pass, so narrowing it down wasn't too hard.