I remember going on Cruises just to eat!
I cruise frequently and have had no problems limiting my food (yet). I order an appetizer for my main meal. Usually have a couple of bites and I'm good. For dessert I order the cheese plate and take sandwich bags with me to keep the cheese in for later or the next morning.
However, I understand kinda where you are coming from. Life before centered around the next meal now not so much. I now enjoy the challenge of getting my protein in and being creative with my ordering of food. The waiters are always very helpful.
I was just talking to someone about the Carnival fiasco and said well other than the smell I would have been fine! When we went in December I had my tub of protein powder and two cases of water, I ate meat at my meals and it was fantastic! however with what they had to eat I probably would have just drank my protein shake and the jerky I had in my bag but boy would everyone else know how we feel! lol