I am unaware of your food situation and plan, but is their something you like just as much as rice?
my suggestion would be to write in okay, I'm going to have this amount of rice today, then if I need/ want anything else, I'm going to eat this (the rice substitute), a certain amount
another Idea could be buying only enough rice to last you for how ever many portions you are having a week.. say you have one per day, buy enough rice for 7 portions
once they are gone, they are gone- you can't be distracted by it because it's not in the house
good luck!