First you must specify whether you mean GM foods that are modified by gene replacement in the lab or by selection and hybridization. Because of the stigma given GMO's by pseudo scientists there are very few directly grown, non processed GM foods. Almost all soybeans grown in the US are GMO and most of the corn and canola. Sweet corn, however, is not GM, but it's a hybrid. Growers must use herbicides to control weeds because there is no GM seed to do it.
It is estimated that 70% - 80% of the processed foods on grocery shelves in the United States contain GMO ingredients. Foods with certain ingredients, like corn (including High Fructose Corn Syrup - HFCS), soybeans, and canola, are almost certain to contain GMOs, since at least 80% (and that figure is probably low) grown in the United States is genetically modified. Meat and dairy products are likely to have been raised on "factory farms," where they are in crowded quarters and possibly given hormones created through genetic engineering, and high levels of antibiotics.
Most fruits and vegetables have not been genetically modified, but sweet corn, sugar beets, and crookneck squash have been: so have potatoes and tomatoes. As far as is known, there are no GMO potatoes or tomatoes that are being sold commercially.
99.9 percent of chickens for raised for meat, 97 percent of laying hens, 99 percent of turkeys, 95 percent of pigs, and 78 percent of cattle currently sold in the United States are raised on factory farms. To date, these animals are not genetically modified, but in many cases, genetically modified hormones, such as rGBH (used in dairy production), and feed that contains GMOs are used.
It all depends on what you mean by genetically modified. We have modified corn and other grain crops for tens of thousands of years. So all of US corn is genetically modified. If you mean GMOs in which pesticide resistant genes of been added to the DNA of the corn, up to 80% are GMO's.
* US * china
Some, though not all, corn and soybeans grown in the US have been genetically modified.
No commercially available potatoes in the US are currently genetically modified, though there is ongoing research on them.
Probably. Because genetically modified foods (GMO) are not required to be labeled as such, it is difficult to know for certain. But it is very likely that food staples produced by huge corporations such as Monsanto or Cargil are genetically modified. I suspect most of the corn, soybeans and wheat produced in the U.S. are GMO.
My strong suspicion is that since ~90% of the corn grown in the U.S. is genetically engineered (GMO), the small percentage of corn grown here that is NOT genetically modified is almost certainly not used to make oil. It's used for organic corn tortilla chips, tortillas etc. So organic corn oil evidently does not exist here in the U.S., if anywhere (legitimately). [I've also been looking for it myself.]
EU (The European Union)
Yesterday, Conneticut became the first US State to legalise the labelling of Genetically Modified foods, and this legislation is accompanied by an unusual requirement that four other states enforce similar legislation.
The Government would have us believe so. Do some research and form your own conclusions.
I don't have a list yet but you can be pretty sure that snacks made with corn from the USA have GMO corn in them. I have read that about 97% of corn grown in the US is GMO. So, Cheetos, Doritos and other snacks imported from the US. You will need to discover the source of the corn which is in Philippine products such as Chippy. I read that GMO corn has been tested but I don't know if GMO corn is grown in the Philippines. In the US GMO soybeans are also grown. So, be careful of imported soy ingredients. See more about GMO at my blog: timotraveling.blogspot.com Click on the GMO and Vegetarian tiles.
The primary genetically modified crops grown in the US are soybean and maize. Rapeseed (used in canola oil) and cotton are also genetically modified.
GM foods are brilliant. WOOOOOO! Genetically modified foods cannot be collectively put into a "good" or a "bad" category. Depending on how they are modified, they may be very good for us, very bad for us, or anywhere in between.
There are many answers to your question, but they can all be summed up to this one answer: Things are genetically modified to increase monetary profit margins. You should next ask how will this modified food affect us all biologically.