I was just dx'd with diverticulosis as well after going through the same procedures a couple of weeks ago. My dr recommended eating lots of fiber and drinking more water in order to keep things moving through. I've added Fiber-sure to my diet now, in addition to already eating lotsa veggies and brown rice. Apparently diverticulosis is caused by constipation (at least according to him), and goodness knows we don't want/need more of that.
Btw, wishing you negative results on the biopsies.