Corn: A Brief History

Did you know that well over half of a typical American diet is derived from corn? It’s true, and if you’ll remember from The Omnivore’s Dilemma, Michael Pollan famously calls North Americans “processed corn, walking.” He’s not wrong, and since more than 90 percent of corn grown in North America is genetically modified, it’s important to understand just how big a role corn plays in the typical North American diet.

GMO corn has only been on the market since 1996. As a reminder, a GMO, or genetically modified organism, is a plant, animal, microorganism or other organism whose genetic makeup has been modified in a laboratory using genetic engineering, also called biotechnology. This process involves rearranging the building blocks of life in experimental ways that don’t happen in nature.

Today, there are at least 232 distinct varieties of genetically modified corn. While not all of those varieties are commercially available, the unfortunate reality is that nearly all corn grown in North America is genetically modified. Let’s take a closer look at the different types of corn and their associated GMO risks.

Sweet Corn

Sweet corn is what you buy on the cob, canned, and frozen in bags. It is harvested early, when the individual kernels still contain a lot of moisture and sugar. The sugars inside begin turning to starch as soon as the corn is harvested, so the fresher it is, the sweeter it tastes!

In years past, genetically engineered sweet corn was uncommon. Unfortunately, Monsanto introduced the first GMO sweet corn in 2011. Now more and more sweet corn is genetically modified each year, with estimates beginning at 10 percent of all sweet corn acreage in the U.S. and Canada.

Some types of sweet corn are genetically modified with the bacteria Bacillus thuringiensis to resist insects. These are called Bt crops, and they cause every cell in the corn plant to produce an insecticide that can’t be washed away. Learn more about Bt crops. Other types of sweet corn are now genetically engineered to tolerate herbicides—especially glyphosate. Farmers can spray Roundup directly on these HT crops, leading to increased herbicide use and the rise of herbicide-resistant weeds. Most types of GMO sweet corn are “stacked” varieties that have been genetically modified with both Bt and HT traits.


Popcorn, also called flint corn‚ is its own distinct type of corn. It makes up very little of all corn grown in North America, and there is not any GMO popcorn available on the market at this time. However, it is still important to consider other GMO risks when purchasing store-bought popcorn. Typical additives including butter, canola oil, sugar, corn syrup, lecithin, enzymes, lactic acid, and all types of “flavorings” present significant GMO risks. Nutritional yeast—my personal favorite popcorn topping—can also be a GMO risk!

Field Corn

Field corn makes up about 99 percent of the corn grown in the United States. This is not the tender, sweet corn most people are used to. It is generally allowed to dry in the field, which removes moisture and converts sugars into starches. Sometimes called “dent corn,” you can often identify this type of corn by its dented kernels.

It’s important to understand that most field corn is not being used to directly feed the human population. In fact, nearly 90 percent of all the corn grown in the US becomes fuel for cars or feed for animals. This is one reason why it is so important to pick non-GMO animal products if you choose to eat meat, dairy, or eggs. Learn more about non-GMO animal feed.

When field corn is used in people food, it tends to be in the form of highly processed ingredients. It’s easy to identify corn products when they are listed as corn starch or corn syrup, but it takes a little more work to keep highly-processed corn ingredients out of your diet. Be aware that there may be GMO corn in citric acid, cellulose, maltodextrin, natural flavorings, vitamins C and E, and anything that says “vegetable” but is not specific.  Don’t forget that spirits such as whiskey commonly contain corn! Read more about corn-derived ingredients.

Genetically modified corn makes its way into so many places that it sometimes feels impossible to avoid it. That’s why we’ve done the work for you. Just look for the Non-GMO Project Verified mark—it tells you a product has been evaluated under the Non-GMO Project Standard and meets its requirements for testing, traceability, and segregation.

The ubiquity of genetically modified corn impacts all North Americans, but residents of the United States should be aware that many refined corn products will not be labeled under the National Bioengineered Food Disclosure Standard. Learn more about the NBFDS. Processed inputs such as oils and sugars are likely to be exempt from labeling, even when they come from genetically modified corn or other GMO crops. If you prefer not to support GMO agriculture, Look for the Butterfly when you shop!

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I eat a lot of popcorn , good to know it’s not GMO! Thanks! And I also use nutritional yeast.. i spay the poped corn lightly with a water mister so my yeast ( mixed with cumin and black pepper) will stick, then another light mist to make sure.. I some times give it another round of flavor half way through the bowel. 😀 delecious! And keeps my bowels very regular too. There is a tribe of Mexican runners in Mexico (Tara Humra…spell?) who eat only corn, and have the longest endurance of any current people on the planet.


Thank you. This was very helpful. I stopped eating popcorn because I thought it was genetically modified also. I wondered about other ingredients, but did not know what to look for. Now I have more information.

Alli Willis

Hi Faith,

Great question. Field corn usually means the type of commodity corn that is used for animal feed and ethanol. People tend to only eat it when it is really fresh, right when it’s at its sweetest. That is the type that is most likely to be genetically modified. Generally speaking, it is safe to assume that field corn is genetically modified unless it is labeled non-GMO or organic.

Our best to you,


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