The Columbian Exchange of foods richly improved the European (and African) diet, not only by improving and diversifying its taste but also, in a more basic sense, by simply increasing Old World societies' abilities to feed more people. Starvation, which had long limited population growth in Europe and Africa, was largely overcome through the transplantation of New World foods.
Three staple crops of the Western Hemisphere—corn, potatoes, and cassava—proved to be much more efficient sources of carbohydrates than wheat, the old European standard. An acre of land planted in corn, potatoes, or cassava yielded twice as many calories as an acre planted in wheat. The increased caloric output of farmers who adopted New World crops helped to fuel a surge in Old World populations. In Ireland, for example, widespread peasant farming of the potato allowed the population to soar from barely one million in 1670 to more than 8 million by the time of the infamous Potato Blight of the 1840s. Cassava, a tropical root plant, thrived in the impoverished soils of equatorial Africa, helping to support a population boom in the Congo. (Much of that new population would end up transplanted, involuntarily, to the New World through the Atlantic slave trade.)
In the cases of both Irish potatoes and African cassava, New World plants transplanted to Old World societies helped to sustain millions of lives—lives that were later used as reinforcements in the European colonization of the Americas. Whether or not of their own free choice—largely not, in the case of both Irish and Africans—millions of people nourished on American foods would eventually follow in Columbus's footsteps to repopulate a New World whose native inhabitants had been decimated by disease.
At the same time, the colonies the Europeans established in the New World soon became efficient producers of not only New World crops, but Old World transplants as well. Thus did North America become a key producer of not only corn but also wheat, while the Caribbean and South America came to host the world's greatest plantations of Old World cash crops such as sugar and coffee.
The Columbian Exchange of foodstuffs vastly increased the health and wealth of Europeans and their colonists in the Americas.