I have done an abstinent cruise and found out on my second day at sea that there was an option to the formal dinner that was served, that was the hardest one for me to get what I needed.  There was an informal dinner in the dining area where the rest of the meals were served at the same time that the formal dinner was taking place.  This dinner was served every night except for the last night of the cruise. It was much easier for me to get what I needed in that atmosphere because the food was served cafeteria style.  Aside from the formal dinners everything else I needed was pretty much available.  But, of course, I did have back up, which I used as an option when I was off the ship touring one of the Islands, or if I just felt like dining alone in my room.