This is what keeps me from getting off track. If I wait until it's time to eat to see what I can or can't eat, I get stressed and have a very high potential of screwing up.
I track my meals a week ahead. Once I got a week done, I started to track a day at a time as the tracker will let me. For example: today I tracked June 7. I get groceries once a week, so when it's time, I already have an ongoing list that I add to each day when I track.