We had a little thought experiment in mind: what if the activists got their wish? What would a world without GMO crops look like?

The results might surprise you.

Nutritional values might be affected.

There’s actually one recent real-world example of a major food processor dropping GMOs for us to peruse, and you might have already seen the shift in your breakfast bowl. This past January, General Mills announced it was removing GM ingredients from original Cheerios and Post Foods said it would do the same for Grape-Nuts.

The switch actually wasn't that hard to make. The main ingredients of the cereals (oats for Cheerios, wheat and barley for Grape-Nuts) didn’t actually change because they were never GMOs to begin with. There are no GM oats (for multiple reasons, but mostly because there’s not a big enough market for oats to justify the cost of research and development). GM wheat has been field tested (and occasionally escaped) but isn't grown commercially; ditto for GM barley.

Basically, what General Mills and Post had to do was find new non-GMO sources of corn starch and ditch genetically modified sugar beets for cane sugar.

There’s one consequence to this slight modification, though. In February, University of Georgia crop scientist Wayne Parrott pointed out to FoodNavigator-USA that the new GMO-free Cheerios have much lower levels of Vitamin B2 (riboflavin) -- 2 percent of the recommended daily value in a serving, compared to 25 percent in the GMO formulation. And the non-GMO Grape-Nuts no longer include vitamin A, vitamin D, vitamin B12 or riboflavin.

You might not think of vitamins as GMO products, but many of the ones that are added to your food come from engineered organisms. Riboflavin, for example, is synthesized with the assistance of genetically modified bacteria. Other vitamins might be synthesized with non-GM microorganisms, but those bacteria might be fed with genetically modified corn or soy byproducts.

“At the moment, there seems to be a shortage of some non-GM vitamins on the market, so they are no longer being added to the cereals in question,” Parrott writes in an email. “Thus it is a case of vitamins no longer added; it is not a case where the ingredients were less nutritious to begin with. Given enough demand, I am sure that these non-GM vitamins would be produced again, though consumers might not like the price.”

But what if, say, Kellogg’s decided to make a commitment to non-GMO Corn Flakes? Would there be any discernable difference in nutrition by avoiding GM corn? Probably not, actually.

“GM crops and non-GM crops have the same nutrient value,” Parrott says.

The machine keeps rolling on

Surely after more than a decade of GMO use, our agricultural system would have to make major changes if genetically engineered crops suddenly disappeared? Well, not quite.

For most major crops, getting rid of GMOs “would simply mean going back to the way they were [grown] up until the 90's,” Parrott says.

There would definitely be adjustments to be made, Parrott says. Farmers would have to plow more, which means more fossil fuel use and erosion, plus labor costs. They'd have to use more insecticide. Many farmers would probably switch from the herbicide glyphosate (which several GM crops are specially designed to resist) to other kinds of weed killers. Plus, any yield gains over the past 20 years would be largely nullified.

So, wouldn’t those changes cause some bump in prices for those processed foods that use GM corn and soy? Doug Gurian-Sherman, a senior scientist at the Union of Concerned Scientists specializing in agricultural policy, doesn’t really think so.

“In most foods, the GMO component is a very minor ingredient, something like corn oil, soya oil, soy lecithin, what have you. In terms of consumer costs for processed foods, even if costs of production went up, the impact on consumers would be tiny,” Gurion-Sherman says in a phone interview. “The vast majority of the cost of processed foods is in the processing, marketing, packaging, and shipping.”

The real pain in the wallet in a post-GMO world would stem from GMOs' most common use: food for livestock.

“The cost of feed would go sky high” if GMOs disappeared, Kevin Folta, a plant geneticist at the University of Florida, says.

That cost of feed would likely be felt as a rise in prices of meat and dairy. But wouldn't the industry readjust somehow? Parrott doesn't think so.

“Producing non-GM grain will never be as cheap and efficient as GM grain production currently is,” Parrott says.

This trickle-down effect on meat and dairy prices would most likely be felt by the poorest citizens.

“Anything that raises the financial or environmental costs of food production always affects the lowest income sectors the most,” Parrott says.

So, our current agricultural system doesn't completely rely on GMOs. But they’re still problematic, argues Gurian-Sherman, a former biotech specialist with the U.S. Environmental Protection Agency, who falls on the more GM-skeptical side of the spectrum than some of his colleagues.

GE crops are “a handmaiden to this type of agriculture that we know is not sustainable,” Gurian-Sherman says. “These crops are being used as an adjunct to industrial agriculture. And industrial agriculture emphasizes growing the same crops over and over again on the same space, which is a recipe for disaster.”

GMO dreams deferred?

Folta says that the true impact of a world without GMO crops would be lost opportunities.

One big loss, Folta says, would be golden rice, a modified version of rice with inserted daffodil and soil bacterium genes that allow it to produce a Vitamin A precursor in its edible parts. Vitamin A deficiency, which is common in poor people subsisting on diets of rice or other carbohydrates poor in micronutrients, is thought to kill hundreds of thousands of children every year and cause hundreds of thousands more to go blind. Golden rice could be a powerful weapon against Vitamin A deficiency, but it has faced opposition from activists.

Folta worries that lingering anti-GMO sentiment is also undermining the progress of untold amounts of research that could realize further potentials of genetic engineering.

“There are thousands of solutions in public labs, not the Monsantos, not the Dows, that will never come out because the process of approval takes so long and is so expensive that the only people that can play in that space are the big companies,” Folta says.

Gurian-Sherman, however, is skeptical about the burdens of the current approval process. If the regulations were truly stifling, he says, you wouldn’t see small companies like Canada’s Okanagan Specialty Fruits moving the non-browning Arctic Apple down the regulatory pipeline.

The real reason that the GMO dream gets deferred, Gurian-Sherman says, lies in the limitations of the technology itself.

“For lot of my colleagues, all the great things that genetic engineering can do are perpetually ‘just around the corner,’” he says. “I have heard the siren song of the value of genetic engineering going back to the mid-1980s, and it’s always better drought tolerance, better nitrogen use, just around the corner.”

While genetic engineering might be useful in certain situations -- responding to a viral infection, like how GM papaya was tuned to resist the ringspot virus -- Gurian-Sherman sees more potential in conventional breeding techniques. By unlocking genes that are already lurking in our food crops, or possibly looking back to the wild cousins from which they sprung, we might be able to achieve the same goals as genetic engineering.

Big companies like Monsanto “probably devote half of genetic research budgets to breeding, not genetic engineering,” Gurian-Sherman says. “And even though it’s just half their budget, they get more out of it.”

In a 2012 report for the Union of Concerned Scientists, Gurian-Sherman examined Monsanto’s DroughtGard corn, the only commercial crop engineered for drought tolerance, and found that it reduced crop losses due to drought by six percent. He estimates that DroughtGard will increase overall corn production by just about 1 percent, while conventional breeding and farming practice changes can increase corn production by about 1.5 percent to 2 percent per year.

Many scientists think it’s far too soon to declare GMOs valueless; drought-tolerant corn is still only in the testing phase.

“Heat tolerant corn is not going to be great everywhere, but there are certain places where it’ll make a huge difference,” Folta says.

Still, why not keep every tool in the box available?

“While a measure of drought tolerance can be obtained with conventional breeding, the best levels are from [combinations] of conventional and GM traits,” Parrott says.