Now one of the things you have to realize is that food means agriculture, and agriculture got started about 10-12,000 years ago when hunter/gatherers realized that instead of having to go in the forest everyday to find the food they wanted to eat, they could take some of these plants and grow them in their backyard.  And in this way, over time they discovered that some plants grew much better than others, they discovered that sometimes if you had two plants growing together, they would cross-pollinate, and you would get some new varieties showing up that were actually better than the ones they had been growing previously. This was the origins of the genetic modification that takes place in plants and this has been going on for 10 or 12,000 years using methods that are considered natural, that is this is the way that nature reproduces.  A way to think about it is, every time we make a baby, that baby is genetically modified, it has a few genes from the mother, a few from the father and doesn't usually look like either one.  The same things happen with plants, when you cross plants you get a mixture of the genes.