The Heller's changed a few things since they wrote the first version of CAD. It use to be Ok to have Zucchini, but in the CALP book they changed it and found that it could trigger some people. I use to eat it when I first started CAD because it showed it as OK. I didn't have any cravings, nor did it stall my weight. My advice would be to go ahead and have it and if it seems like you have cravings afterward, then you know you probably should not have it, or if you find you are not loosing weight then stop eating it. They did the same thing with Broccoli.

Hope this helps.