790 AD would put you in the mid-late Classic period (generally considered to be 250-900AD or so).

As the typical Mayan, the staples of your diet would be maize, beans, and squash. Unlike modern western agricultural practice of monocropping (growing only one type crop in a given field), the Maya would grow these in together, in the same field at the same time. This created synergies. The cornstalks would provide support for the beans to climb on. The leaves of the squash would cover the ground and prevent weeds from growing. The beans act as a fertilizer by providing nitrogen in the soil due to nitrogen-fixing bacteria in their roots.

Chocolate was also an important part of the diet, even for non-elites. It was typically ground up and served in a thick, bitter hot chocolate drink or used in sauces.

Fruits such as papaya, sapote, and avocados were also present in the Mayan diet.

As far as meat goes, domesticated turkeys were raised in pens and turtles and fish were eaten in areas where they could be caught. Additionally, deer were a common component of the diet.