The cuisine of ancient Rome was both similar and dissimilar to the Italian cuisine of today. In antiquity, of course, there were absolutely no products that came to us from the New World. No ketchup, no chili peppers, no beans, no potatoes…
Beef was barely eaten, and the main and most popular meat dish (like chicken nowadays) was hare. There were more fish in the sea than now, so fish and seafood made up a large part of the menu. Only nowadays Mediterranean oysters are a delicacy, but back then they were quite an everyday food of coastal residents.