If you suspect at all that you aren't eating enough fiber I would at the very least try out some fiber supplement. Target sells some generic kind for an ok price, it's basically just psyllium husk with a bit of orange flavoring (you mix the stuff up fast and shoot it down, else it gels up). If you get too many runny poops it's usually a lack of fiber, and at least in the immediate term supplementing can help (or when you just haven't got much fiber in you in the last 48 hours).