From their website-
Can Special Diets be Accommodated?
Guests with diet requirements can be accommodated on board. We do not have Dieticians onboard; therefore, we can only offer assistance with simple requests such as the method of preparation of menu items. The special diet requirements need to be arranged with the guest's Headwaiter on the first night of the cruise. Every menu (in the dining room) has Spa Carnival Cuisine Fare. These items are lower in calories, sodium, cholesterol and fat. Salads are prepared with diet dressing. Desserts are prepared with Sweet'N Low or NutraSweet instead of sugar. In addition, each menu has one vegetarian entree. Low-cholesterol egg substitute is available upon request as well as diet jellies at breakfast.
The following simple diets can be prepared onboard:
The following food is not available onboard:
Baby Food and Formula
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007, Celebrity Silhouette 2013