packed lunches
 

As you have paid for full board on the cruise, can you ask for a packed lunch to take on your excursions? Has anyone ever done this?

Some Countries do not allow food to be taken off the ship
I would check the Customs first

In Mexico there is several big garbage barrels full of food that people try to take off the ship ;)

Sample the food of the Country you are visiting

No, there are restrictions on taking food off the ship. I think part of traveling is trying some of the local food. You will find lots of interesting food stands and restaurants in the Scandanavia/Baltic. In Copenhagen walking down the mile long pedestrian mall is fascinating.