I kinda though when you have to go....you have to go. It isn't good to hold it in, although for a short time and not often it won't hurt you, may give you a swollen tummy and be harder to pass due to the loss of fluids.
I would think if you ate more food early in the day time and less in the evening and none at night, that might help. I'd eat lots of fiber early in the day as well. I get up and eat a high fiber breakfast and eat jalapenos to make sure I go before I leave the house.