Indeed, Norway protects farmers in order to ensure agriculture is kept alive, as well as keeping remote areas habitable. I think that's a good precaution. However, Norwegian farms are very inefficient compared to for example Dutch farms. And given that energy is very cheap in Norway, they could have built a lot more greenhouses.

As a foreigner living in Norway, I can say the food in the supermarkets is quite bad compared to what you get elsewhere. And while the onions, cabbage and root vegetables that are in the shelves are produced in Norway, most of the other products actually come from elsewhere, mainly from the Netherlands and from Spain. Just check the country of origin labels next time you do shopping. I know I am often wrong in my assumptions of where food is coming from.