If you go to the Discovery Cove site, add the code AMXDM10 and it will describe the American Express discount.
As far food, it is all included in price of ticket. Continental breakfast, lunch with many offerings and you can get whatever you want even more than one thing, snacks bars are open most the day and all free as well, as much as you want. This is a big savings we mentally calculate out of the price had we been at another park.
Also a free picture when you arrive, no charge for parking and the free ticket to another one of their parks....it is still an expensive day, but it is really something special

and worth doing at least once.
This is right off their site:
Reserved all-inclusive dolphin swim package.
All day self parking, use of snorkel gear, wetsuits, towels, sunscreen, showers, lockers and changing rooms.
A light complimentary continental breakfast, a freshly prepared lunch, plus snacks and beverages throughout the day.
An unlimited use pass for up to 14 consecutive days to your choice of either SeaWorld Orlando, Busch Gardens Tampa Bay or Aquatica.