GMO foods are plants, animals, or microorganisms whose DNA has been altered in a laboratory to introduce traits that don’t occur naturally through conventional breeding. In the United States, more than 90% of corn, soybeans, and cotton are grown from genetically engineered seeds, making GMO-derived ingredients extremely common in packaged foods, cooking oils, and animal feed.
How GMO Foods Are Made
The core technique behind most GMO foods is recombinant DNA technology, which means combining genes from different organisms. A gene that produces a useful trait in one species, like a soil bacterium’s ability to repel insects, is isolated and inserted into the DNA of a crop plant. The resulting plant can now produce that trait on its own, passing it to future generations of seeds.
Traditional genetic engineering inserts these foreign genes somewhat randomly into the plant’s genome. A newer approach called gene editing (most commonly CRISPR) works differently. Instead of adding DNA from another species, scientists make precise changes to genes the plant already has. For example, editing an existing gene in soybeans to produce healthier oils. Because gene-edited plants often contain no foreign DNA, many countries, including the US, don’t regulate them the same way as traditional GMOs. The plants they produce can be indistinguishable from those created through conventional breeding.
The Most Common GMO Crops
Only a handful of crops account for the vast majority of GMO acreage, but they show up in a huge range of everyday products. As of 2025, 96% of US soybean acres, about 92% of corn acres, and 93% of upland cotton acres are planted with genetically engineered seeds. Alfalfa, canola, and sugar beets also rely heavily on GMO varieties.
The two dominant traits engineered into these crops are herbicide tolerance and insect resistance. Herbicide-tolerant plants survive when farmers spray weed-killing chemicals, allowing weeds to be controlled without damaging the crop. Insect-resistant varieties produce a protein derived from a naturally occurring soil bacterium called Bacillus thuringiensis (Bt) that kills specific pests when they eat the plant. About 87% of US cotton acres and 84% of corn acres are now planted with “stacked” seeds that combine both traits in a single variety.
If you eat corn tortillas, use soybean oil, sweeten coffee with sugar (about half of US sugar comes from sugar beets), or wear cotton clothing, you’re almost certainly using products from GMO crops.
Beyond Pest Control: Nutritional GMOs
Most GMOs on the market today were designed to help farmers grow crops more efficiently, but a growing number aim to improve the food itself. Golden Rice is the most well-known example. Scientists inserted genes responsible for producing beta-carotene (a precursor to vitamin A) into rice, creating grain with a golden color and 7.9 micrograms of beta-carotene per gram of dry rice. The goal is to reduce vitamin A deficiency in regions where rice is a dietary staple.
Gene editing has expanded these possibilities. Soybeans have been modified to produce higher levels of oleic acid (a heart-healthy fat) and lower levels of linoleic acid. Researchers have used CRISPR to boost iron and zinc levels in wheat, increase vitamin E content in barley, and reduce gluten in wheat for people with sensitivities. Tomatoes have been edited to accumulate more of a compound called GABA, which may help regulate blood pressure. These nutritional improvements represent a shift from GMOs that primarily benefit farmers to ones that could directly benefit consumers.
Safety of GMO Foods
Every GMO food currently sold on the international market has passed safety assessments conducted by national regulatory authorities. The World Health Organization’s position is that these foods “are not likely to present risks for human health,” and that no health effects have been demonstrated in the general population of countries where they’ve been approved. No allergic effects have been found from GMO foods on the market.
That said, the WHO also emphasizes that each GMO food needs to be evaluated individually. Different products contain different genetic modifications made in different ways, so blanket statements about all possible GMO foods aren’t scientifically meaningful. The safety record applies to products that have gone through the established assessment process, not to the concept of genetic modification in general.
How GMO Foods Are Regulated in the US
Three federal agencies share oversight of GMO foods. The USDA’s Animal and Plant Health Inspection Service evaluates whether a modified plant could become a pest or harm other plants before it’s allowed to be grown outdoors. The FDA’s Center for Food Safety and Applied Nutrition assesses whether the food is safe to eat. And the EPA regulates crops engineered to produce their own pest-killing proteins, evaluating the environmental and dietary risks of those built-in pesticides.
For labeling, the National Bioengineered Food Disclosure Standard has been mandatory since January 1, 2022. You won’t see the word “GMO” on US food packaging. Instead, the official term is “bioengineered.” Products made entirely from bioengineered ingredients must say “Bioengineered food” on the label. Multi-ingredient foods with at least one bioengineered ingredient must state “Contains a bioengineered food ingredient.” Companies can disclose this through plain text, a green symbol with the word “BIOENGINEERED,” a scannable digital link, or a text-message option. If you’ve noticed a small green circle with a sun and field design on your food packaging, that’s the bioengineered disclosure symbol.
Environmental Effects
A large-scale meta-analysis published in PLOS ONE found that GMO adoption has reduced chemical pesticide use by 37% on average and cut pesticide costs by 39%. Insect-resistant crops drive most of that reduction, since the plant itself handles pest control that would otherwise require spraying.
The picture is more complicated for herbicide-tolerant crops. While they’ve reduced herbicide use in some situations, they’ve also led to increased spraying of broad-spectrum herbicides in others. When farmers rely on a single herbicide year after year, weeds can develop resistance, prompting heavier applications or the use of additional chemicals. This tradeoff is one of the more legitimate environmental concerns surrounding GMO agriculture, even among researchers who support the technology overall.
Yield gains tell a clearer story. GMO crops generally produce more food per acre than their conventional counterparts, with insect-resistant varieties showing the largest improvements. Higher yields from the same amount of land can reduce pressure to convert forests or grasslands into farmland, which carries its own environmental benefits.