We have been trying to plan the same thing and here is what I figured out. We will be staying at Captain Morgans the first week of May.
You can eat cheap and you can eat expensive. It is your choice depending on your budget. What we did is plan for about $100 a day for meals not including the 1-2 expensive dinners we are planning.
This is how I calculated it:
Breakfast $10 pp
Lunch $15 pp
Dinner $25 pp
This should include beer with meals but maybe not alcohol drinks which are more expensive. Consider that you also may be getting some meals included in an excursion - especially if you are planning an all day thing. I understand that the prices are all comparable to the states. It has been several years since I was last down there and I remember finding the least expensive, best tasting meals right in town. I am sure the same applies.
I have also heard that people just tend to eat less because of the warm weather. However, I am not taking that into consideration since I plan on eating my way from one end to the next.
Hope this helps