The process of producing a GMO used for GM Foods may involve taking DNA from one organism, modifying it in a laboratory, and then inserting it into the target organism's genome to produce new and useful genotypes or phenotypes. Such GMOs are generally referred to as transgenics. Other methods of producing a GMO include increasing or decreasing the number of copies of a gene already present in the target organism, silencing or removing a particular gene or modifying the position of a gene within the genome.

History
The first commercially made very big genetically modified whole food crop was the Flavr Savr tomato, which was made more resistant to rotting by Californian company Calgene. Calgene was allowed to release the tomatoes into the market in 1994 without any special labeling.  It was welcomed by consumers that purchased the fruit at two to five times the price of regular tomatoes. However, production problems  and competition from a conventionally bred, longer shelf-life variety prevented the product from becoming profitable. A variant of the Flavr Savr was used by Zeneca to produce tomato paste which was sold in Europe during the summer of 1996.  The labeling and pricing were designed as a marketing experiment, which proved, at the time, that European consumers would accept genetically engineered foods.

The attitude toward GM foods would be drastically changed after outbreaks of Mad Cow Disease weakened consumer trust in government regulators, and protesters rallied against the introduction of Monsanto's "Roundup-Ready" soybeans.  The next GM crops included insect-resistant cotton and herbicide-tolerant soybeans both of which were commercially released in 1996. GM crops have been widely adopted in the United States. They have also been extensively planted in several other countries (Argentina, Brazil, South Africa, India, and China) where the agriculture is a major part of the total economy. Other GM crops include insect-resistant maize and herbicide-tolerant maize, cotton, and rapeseed varieties.

Between 1995 and 2005, the total surface area of land cultivated with GMOs had increased by a factor of 50, from 17,000 km² (4.2 million acres) to 900,000 km² (222 million acres), of which 55 percent were Brazil.  In the US, by 2006 89% of the planted area of soybeans, 83 percent of cotton, and 61 percent maize was genetically modified varieties. Genetically modified soybeans carried herbicide tolerant traits only, but maize and cotton carried both herbicide tolerance and insect protection traits.