In 2008, Duane Grant, who runs farms in Idaho and northern Oregon, began growing sugar beets from seeds that were genetically modified. As a result, he says he now uses fewer chemicals, tills the soil less often and gets larger yields from the same acreage — increasing profits and reducing his environmental footprint along the way.

"I am proud of that fact," he said.

But that pride does not translate into support for a burgeoning consumer movement that would have mandatory labels placed on products containing sugars like his, such as juices, soft drinks and breakfast cereals, and on any other product containing a genetically modified organism, or GMO. Grant considers such labels irrational — a sentiment that aligns with the broader food industry, which has been spending tens of millions of dollars in recent years to avoid them, fearing they would drive customers away.

Despite two decades of assurances from biotechnology firms, food processors, federal regulators and even a substantial share of scientists that GMO foods are safe, ballot initiatives and citizen petitions seeking labels on GMO foods are springing up as quickly as the industry can pay — or sue — to defeat them. Meanwhile, sales of foods labeled GMO-free have been steadily gaining ground on consumer shopping lists, and polls suggest that more Americans than ever favor labels that identify GMO foods.

This has even some supporters of genetic engineering wondering if it's time to rethink the labeling question. "If you give people a choice and value, that wins," said David Ropeik, a risk-communication consultant. He has begun calling on the industry to let go of its "fear of fear" and embrace GMO labeling, which is required in at least 64 other nations, including Japan, Australia, Russia, Brazil and more than a dozen European countries.

But Grant, like many industry stakeholders, remains skeptical. "To allow popular perception of harm — or benefit — to be the basis for mandatory labeling would not result in food being safer," he argued. "It would result in the scientific community being pushed to the sidelines in favor of food-fad-of-the-day mob regulation."

Whether or not that's true, food makers are spending lavishly to avoid mandatory GMO labels. In 2012, for example, opponents of a California labeling proposition — including Monsanto, ConAgra and other genetically modified seed makers alongside food companies like Sara Lee, Coca-Cola and Kellogg's — spent a staggering $46 million, primarily on lobbying and advertising, to defeat the measure. Similar efforts in Washington the following year prompted the state's attorney general to sue the Grocery Manufacturers of America (GMA), alleging that the leading food industry lobby was hiding the identity of the contributors to its anti-labeling campaign in violation of state election laws. The GMA eventually came clean, revealing that dozens of contributors — including Nestle, Del Monte, Coca-Cola and Hershey — had chipped in $7 million to kill the measure.

In almost all such battles, the companies easily outspend label supporters.

Monsanto and Dupont Pioneer, for example, were among a long list of food industry interests that contributed over $15 million to defeat a labeling measure in Colorado during November's elections, according to state records. Supporters of the bill managed to raise a tiny fraction of that amount. The initiative failed. Dupont, Monsanto, Kraft Foods, PepsiCo and other food industry players pumped more than $30 million into efforts to quash a similar ballot initiative in Oregon — twice the amount supporters were able to muster.

The industry is now locked in a fierce legal battle with Vermont, which passed a GMO labeling law last year, and companies have lobbied hard for federal legislation that would bar other states from following suit. A bill that would do that was introduced last spring by Rep. Mike Pompeo, a Republican from Kansas who, as it happens, received the largest single contribution — $10,000 — from the GMA for the 2014 election cycle, according to federal data. The bill did not make it out of committee, but Heather Denker, a spokeswoman for Pompeo's office, said he plans to reintroduce the bill in coming weeks.

The industry justifies all these expenditures on a variety of grounds. For starters, companies say, a hodgepodge of differing state labeling laws would be unworkable, and even a federal labeling rule would make food more expensive. They also argue that genetic modification, which involves the insertion of foreign genes into an organism — so far mostly crops like corn and soy — so that it expresses a new and ostensibly desirable trait, is really just one among a variety of plant breeding techniques that have been used for decades without complaint.

More substantively, GMO supporters argue that there is no evidence to suggest genetically modified foods present any more risk than conventionally bred fare, a view generally held by a long list of scientific organizations, including the American Medical Association, the American Association for the Advancement of Science and the World Health Organization.

Taking a similar position, the U.S. Food and Drug Administration, which regulates food from GMO crops in conjunction with the U.S. Department of Agriculture and the Environmental Protection Agency, has seen fit to leave GMO labeling a strictly voluntary affair.

"As a public health agency, we base our policy decisions on the best science available," said Theresa Eisenman, an FDA spokeswoman, in an emailed statement. "The agency is not aware of any information showing that foods derived from genetically engineered plants, as a class, differ from other foods in any meaningful or uniform way or that, as a class, such foods present different or greater safety concerns than their non-GE [genetically engineered] counterparts."

Although the FDA's review process is voluntary, virtually all producers of new GE products submit them to the agency for approval. Since the mid-1990s, the FDA has signed off on over 150 varieties of genetically engineered crops, though not all proved commercially viable. Most GMO-derived ingredients found on shelves today are from crops that were tweaked to improve resistance to pests and certain herbicides, but newer products with consumer-facing traits are in the pipeline. This includes the Arctic apple, which has been engineered to resist browning.

On Feb. 13 the USDA determined the apple was safe to grow, and the FDA is currently reviewing it.

Eisenman also said that the agency is reviewing two citizen petitions urging the FDA to create a mandatory GMO label but that no decisions has been made — much to the chagrin of many consumers who remain unconvinced that GMOs are safe.

A survey published last month by the Pew Research Center, for example, found that while nearly 90 percent of scientists surveyed said they considered genetically modified foods safe to eat, only 37 percent of the general population agreed. An ABC News poll from last summer found similar results, with more than half of respondents saying they believed GMO foods were unsafe. In a 2013 New York Times survey, 93 percent of respondents said they wanted GMO ingredients identified on food labels.

Critics of such surveys argue that they only demonstrate ignorance of GM technology. Ropeik, for example, pointed to a 2013 study conducted at Rutgers University, in which participants were asked, in an open-ended question, what sort of information they would like on their food labels that isn't already there. Only 7 percent mentioned genetic modification. A more recent survey from Oklahoma State University found that 80 percent of respondents said they supported mandatory GMO labels. The same large percentage, however, also wanted labels on foods containing DNA.

Such cognitive dissonance suggests to industry stakeholders that environmental advocates are simply exploiting consumer ignorance to force a label on technology they don't like. "It's clear to us that it's really meant as a skull and crossbones," said Cathleen Enright, the executive vice president for food and agriculture for the Biotechnology Industry Organization, a trade group representing Monsanto, DuPont and other GE seed makers. "We shouldn't be using labels as a scare."

Scott Faber, the vice president of government affairs with the Environmental Working Group, a public health advocacy based in Washington, D.C., disagreed. "If you're framing this as a debate about technology, you're really missing the bigger picture," he said. "It's about what consumers are entitled to know, broadly, about their food."

He argued that the jury remains out on questions of GMO safety, not just at the dinner table but also in the fields, where cross-pollination with conventional crops is difficult to control and where heavy reliance on GM seeds is contributing to the emergence of new herbicide-resistant weeds, which in turn drives farmers to ramp up use of toxic chemicals. "These things have only been in the market for 15 years," Faber said, "and they've not been submitted to long-term studies, so it's still way too early to render a judgment one way or another on their safety."

In the absence of consensus, the marketplace may be providing the differentiation many advocates seek. Labels certifying GMO-free foods are booming, with the lead certifier, the Non-GMO Project, placing its imprimatur on over 20,000 food, beverage and body care items. Nielsen, the market research firm, said sales of such products increased 15 percent last year, to nearly $10 billion, and it ranks the GMO-free sector among the fastest-growing food trends in the market today.

The USDA's organic certification already acts as a vouchsafe against GMO ingredients, and Whole Foods has taken the lead among major retailers in catering to consumer demand, requiring that by 2018, all products in its U.S. and Canadian stores either avoid GMOs or carry labels to indicate that they contain them.

U.S. Secretary of Agriculture Tom Vilsack has floated an even broader long-term solution: placing special bar codes on food packages that consumers can scan with their smartphones, obtaining all the information they could ever want about the food involved — where it was made, how it was processed, whether it was grown using hormones or antibiotics, what sort of allergens it might contain and, of course, whether it involved genetic modification.

Brian Kennedy, a spokesman for the GMA, suggested that the bar code solution has merit. "Our members are always looking for ways to use technology to provide consumers with more information about their product choices," he said. Until that happens, though, the GMA and its like-minded industry partners plan to keep battling the mandatory label movement — and to let voluntary non-GMO labeling provide consumers with the choice they're looking for.

In Idaho, Duane Grant suggested that identifying and labeling products that don't contain GMOs would be a lot easier to do these days anyway. "The fact is, about 80 percent of the food in the U.S. now contains ingredients produced using GM technology," he said, "and it has been that way for years."