YepAmericans have been eating modified food for Oh... ever. Almost every vegetable strain we eat on a daily basis has been modified.
http://www.stonepages.com/news/archives/000432.html
In a study that compared the genes of corn cobs recovered in Mexico and the southwestern United States, researchers found that three key genetic variants were systematically enhanced, probably through selective cultivation, over thousands of years. The technique was not as sophisticated as the methods used for modern genetically modified crops, but experts said that the general effect was the same: genetic traits were amplified or introduced to create plants with improved traits and greater yield.