Potatoes, maize/corn, tomatoes, chile peppers, chocolate. Old-world food was a hell of a lot more boring before the Columbian exchange. It transformed food so

Potatoes, maize/corn, tomatoes, chile peppers, chocolate. Old-world food was a hell of a lot more boring before the Columbian exchange. It transformed food so much that most of what we think of as "traditional" cuisines in various old-world countries or regions are largely products of the 16th century or later. The exchange also cut the rate and severity of previously-regular famines dramatically, enabling a huge population boom and economic expansion (see: Mann's 1493). Mainly due to maize and potatoes, maize being incredibly efficient on a calories-per-acre basis, and potatoes being stupid-easy to grow almost anywhere, having decent caloric content and not-bad nutrient profile (gotta eat the skin, though) and being easy to store for the medium-term to cover gaps when other crops fail (you just... leave them in the ground)