I wouldn't ask for a "diet" menu. I don't know what you would end up with. But it's easy to eat healthy just by making the right choices from the regular menus and buffet selections.
I ate breakfast at Topsiders and had a great choice of cererals, fruit, lowfat yogurt. Lunches have a chicken choice and again lots of fruits and vegies to pick from. On
Castaway Cay, a little bit away from Cookies Barbecue, there is a fruit stand. I love fish and had that as my choice every evening and included a dessert. (They usually aren't that big!) Watch out for the extra calories in alcohol. I only had a couple of drinks that week.
If I was hungry inbetween meals, I headed to Scoops and hit the fresh fruit bar. We have always taken our cruise in January. We live in Iowa, so our winter fruit choices are apples and oranges ... so I LOVE the variety of fruit that's available. My favorite is papaya. I was looking for some one night in one of the clubs and couldn't find any that was cut up, only some whole ones that were being used as a garnish on the platter. The CM that was helping serve, asked me what I was looking for and I told her. She looked around, grabbed the "garnish," put it on my plate and then handed me a knife with a big smile and said, "Enjoy!"
On the seven day cruise, I was never hungry, always felt I had delicious and different food choices and without trying, lost 3 pounds!
Enjoy your cruise!
Barb W.