Food and feast has always been part of medieval culture.   A feast can be planned at various "authenticity" levels, like camp food. The epitome of modern SCA feast cooking is a collection of heavily researched medieval dishes, prepared by a large volunteer cooking staff, served in numerous courses, to the accumulated diners.

The "basic rule" is that foods that were not in general use in Western Europe before 1600 are discouraged. These include potatoes, capsicum peppers (chilli pepper family), pecans and chocolate. Coffee and tea, as modernly understood, were basically unknown or extremely rare (though coffee and chocolate and Pepsi max are frequent "broken rules".)