Yup. I read (somewhere, I think in the 1491 article) last night that greater than 50% of the worlds food supply today is dependent on plant crops that originated in the Americas. The discovery of the Americas caused a population explosion in Europe.
The first effect was to enlarge the diet. The main effect; was American Food could feed a family on a small area of ground, took a couple of hundred years to get around. Kinda brings us up to the End of the Little Ice Age.