In CAD zucchini is allowed, in CALP they disallowed it. It is very low carb so I haven't stopeed eating it. Just watch yoruself and see if you have any cravings.

Just on a side note, both CAD and CALP have you start on the basic plan which is 3 meals a day, no snacks. If you don't find yourself losing, or having problems with cravings, you might go back to the basic plan, at least to start, then move up to the plan that includes snacks. (the CAD book states this clearly while the CALP book kind of sounds like it encourages more snacks, so take it however)