The Pew Research Center recently polled Americans on their concerns about genetically modified foods. Predictably, given the popular consternation around GMOs, a considerable plurality said they had concerns: 49 percent worried about the effects of GMOs on our health; the same number believed that GMOs would harm the environment.

But McKay Jenkins, a journalist who spent several years researching GMOs, says both of these concerns fundamentally miss the mark. In his new book, “Food Fight: GMOs and the Future of the American Diet,” Jenkins makes the case that it’s not GMOs we should single out for criticism — it’s the industrial agricultural system that they power.

After all, Jenkins points out, genetic engineering has thus far been limited to America’s largest commodity crops, such as corn and soybeans. (According to the Department of Agriculture, 92 percent of U.S. corn acres are planted with GM varieties; for soybeans, it’s 94 percent.) Both corn and soy are typically grown in vast Midwestern monocultures, doused with nitrogen fertilizers and synthetic pesticides. They also supply the vast amounts of corn syrup, soybean oil and cheap livestock feed needed to power both the fast food and processed food industries.

I first spoke to Jenkins last month for a story on the first genetically modified apple, which recently hit stores in the Midwest. I called him up again last week to chat about the big-picture, structural problems with GMOs in more depth. This conversation has been edited for clarity and length.

Q. Before we get too deep into this, I wanted to ask you a quick procedural question: You know, better than I do, that it’s very difficult to report on GMOs. Everyone claims to have science on their side. Everyone also has very strong feelings on how that science should be interpreted. How did you go about assessing the evidence?

A. Before I started writing this book, the journalists who I knew who had tried to write about it previously warned me that anybody who touches GMOs gets burned. People are so worked up on both sides that no matter what you say, somebody’s going to scream about it. As a journalist, you know that anytime that’s true there’s something worth looking into.

On this issue there’s a lot of stuff that is tossed around that’s confusing on both sides. And when I say “both sides,” I realize there aren’t just two sides to the GMO issue. You have industry that is trying to convince you that all GMOs are fine, and then you have anti-GMO groups that have quote-unquote science they’re reporting that’s not necessarily reliable, and you have global debates, and local debates, and debates over labeling and debates over health and debates over ecological impacts. All these different things are all going on at the same time.

I decided pretty quickly that I wasn’t going to try to get into the debate of whether eating a genetically altered tortilla chip was going cause you to get cancer or not. That’s pretty much the only question general consumers seem to have, but that was not the question that most interested me. The screaming on both sides of that question is so loud and so shrill that I can’t hear any truth in it. I think it’s safe to say that the vast majority of scientists seem to have agreed that genetic engineering as such is not a cause for concern. Now even as I say that, it’s important to know there are plenty of scientists who don’t agree. But I still don’t think that’s the most important question.

Instead, I went in search of GMO scientists that had the larger question of sustainable, nutritious food in mind. I wasn’t interested in finding out what someone who works for a giant agrochemical company thought about whether GMOs could make monoculture corn better. The pro-GMO scientists I wanted to talk to were the ones who were thinking about using genetic engineering to solve, for example, nutritional deficiencies or to solve drought problems or to solve fossil fuel overdependence. People who were using technology in ways that would advance the goal of sustainable agriculture.

Q. That’s actually a main criticism of the book, right — that GMOs are part of an agricultural system that is not environmentally or socially sustainable?

A. Yes. Another category of scientists I spoke to were people like Wes Jackson and his crew out at the Land Institute, who think the GMO question is at best a part of this problem, and at worse a distraction from the larger problem — that really GMOs are just the latest version of a 30- or 40-year-old industrial food system that has gone completely off rails.

By focusing so much on GMOs, you’re not paying attention to species loss or the decline in aquifers or soil depletion or greenhouse gasses or all the other problems tied up on industrial food production. And I’m sympathetic to that argument. I think GMOs have gotten a lot of attention because they elicit a visceral fear from people, but really we have a lot of other agricultural problems that predate GMOs. If you think about factory farming or fossil fuels or toxic chemicals or soil loss — those things all existed before GMOs, and GMOs just scaled them up.

Q. What do you mean when you say GMOs just “scaled up” agriculture’s problems?

A. The short version is that GMO technology, along with synthetic fertilizers, has allowed industrial-scale farmers to grow a very small number of crops incredibly efficiently. These firms are not out there making GMO zucchinis and broccolis and red peppers and all that — they’re making corn and soybeans and canola oil and sugar beets. They’re making components that either go into processed food, or are used to feed processed, industrial meat.

That’s been great for the food industry, because they can provide a huge amount of calories and lots of different kinds of food products. You have something like 230 million acres of GMO corn and soybeans in the Midwest, which is then processed into the food that we eat — fast food or those processed foods that just need to be popped into the microwave that you buy in the supermarket. The average supermarket has something like 46,000 different products in it, and a good percentage of those are built out of those couple of grains, which are mostly GMO. The GMO technology has simply allowed an already industrial system to become even bigger and more efficient.

Q. I remember the first time we spoke, you said that GMOs are at heart of the obesity epidemic, that they’ve fueled this whole system that’s wrecked havoc on American health. How did you make that connection?

A. If you back these conversations up and you ask what are people eating that is making them obese, the answer is lots of soft drinks, lots of fast food, lots of processed food. There’s no disputing that. Everyone agrees on that. And then you back that up and say, “What are those things made of?,” And the answer is always, “Well, they’re mostly made out of corn or soybeans.” The corn is processed into high-fructose corn syrup, which goes into sodas; the corn and soybeans go into feeding the animals that become fast-food hamburgers or chicken nuggets.

To say that GMOs cause obesity is disingenuous. But it’s also true that GMOs are a central technological component of the system that is providing this kind of food in that kind of quantity.