There's 12 Gran Bahia Principe's across Mexico, Jamaica and DR.
Are you after info on one in particular ?

According to past posts I see you are about off presumably to the Riviera Maya resort.

If you haven't already left and you are off to the COBA, Akumel etc, unfortunately the food is all a matter of taste.

You can book the a la cartes at customer services in reception but they only have the blurb for the local hotel and are not forthcoming or maybe it was us. For instance, we stayed at the Coba and told them we wanted a steak to which the reply was there wasn't a steakhouse at this hotel.
We found later that it was in the Tulum, decided we wanted to go there so went back to customer services and booked it with no problems. So you have to visit all the hotels to find out which a la cartes exist and to see the menus.

We spent most of the time at the Coba so there is the main buffet restaurant where you get breakfast dinner and tea, there is a snack bar by the pool which does their version of burgers. Chips are normally OK. Every now and again they have a cook up at the main pool.

Similar things happen at the other hotels and you don't have to book at the buffets, just turn up and eat. There is a dress code, which makes visits from the beach and pools difficult unless you have something to change into, however the outdoor snack bars catered for those. One couple we met over there always ate at the Tulum buffet as they felt it was better. Ours didn't find any difference when they went with them one day.

Normal AI buffet rules apply:-
Check out all the offering before you start filling up. Get the harder to get to hot food first, ie toast (no fried bread) then chef cooked eggs, pancakes, meat etc. Then fill the plate with the readily availablr rest of your selection on the way out to the table (you already know what you want and where it is from the reconnoitre).
It still surprises me that people will, for example, get their bacon from the tray, decide they want a fried egg to go with it, so stand in the queue for a fried egg, spot that it is on the plate and everyone else has toast or bread so then go and toast some bread, get back to the table and moan that the food is cold!
Unfortunately at this set of hotels you do have to double check as we found they often brought the meat out from the kitchen cold and used the reheat trays to "reheat it". The thing that got me the most was the egg fried rice. There was a chef cooking up chinese food and by luck the first night it was hot and was one of the tastiest I have found. Every other night for the two weeks I could not get it hot as they just put it on a plate on the shelf between the cooker and the queue to go cold. It was always tasty but stone cold!.
On site by the main pool was the Italian/mediterranean restaurant which was quite nice.

As I said at the beginning it is a matter of taste and the hundreds of happy people showed that a wide variety of tastes were catered for.
You should have a good time, btw the inclusive meals at Xcarat and XelHa were both very nice.

Best meals we had last year were at the Oriental restaurant in the Hacienda area - Italian was very pleasant especially for lunch - the worst meal we had was at the Meditteranean restaurant - the aircon was freezing and the service lackadaisical.