Final answer:
Corn, originating from the New World, had a significant impact on Old World diets by improving nutrition, being easy to grow, and widely spreading globally after Columbus's voyages.
Step-by-step explanation:
The most significant contrast between Old and New World food production lies in the crops that originated from the New World and had a profound impact on the diets of those in the Old World. One such crop is corn (or maize), which, after being introduced to Europe following Columbus's voyages, quickly became a staple crop. Corn's high adaptability allowed it to be cultivated in areas in China that were previously unfit for farming, contributing to its global proliferation.
The introduction of New World crops like corn vastly improved nutrition by providing a reliable source of carbohydrates and contributed to population growth and urbanization. Their ease of growing enabled many regions to support larger populations, and their degree of spread led to the crop's dominance in countries all over the world, becoming the third-most planted field crop after wheat and rice. Such exchanges of crops and technology during the period known as the Columbian Exchange significantly altered global dietary patterns, economies, and social structures.