Marion Nestle is the Paulette Goddard Professor in the Department of Nutrition, Food Studies and Public Health at New York University. Nestle is the author of nine books including Food Politics: How the Food Industry Influences Nutrition and Health (Berkeley, 2007).

Nestle spoke with Nutrition Action Healthletter's Bonnie Liebman about how and why the food industry is involved in nutrition science.

Q: Does industry funding influence scientists?

A: Yes. Study after study and commentary after commentary shows that it does. It’s been seen with research on tobacco, chemicals, energy, and pharmaceutical drugs, which are the closest to foods.

The research on Big Pharma’s influence on physicians’ prescribing practices or research goes back 40 years. There is evidence that just a tiny gift from a drug company—a pen and a pad of paper—is enough to change prescribing practices. And the physicians don’t have a clue.

Q: They’re not aware of the influence?

A: No. It’s unconscious. They think other people are influenced by industry funding, but they’re not. They have no intention of selling out. In fact, they deny it vehemently.

Often, they didn’t approach food companies for research funding with the idea that they were going to be bought or working for the companies’ interests.

That wasn’t the intention. The intention was just to get money for research. The influence is unrecognized, unintentional, and unconscious.

Q: What did your informal research show?

A: For a year, I collected studies that were funded by the food industry. This was a casual collection. I found 168 studies, and 156 of them had results that were favorable to the sponsor. Only 12 didn’t.

Q: Do systematic reviews agree?

A: Only about a dozen reviews have looked. Most of the evidence is consistent with what drug studies show. They find that industry-funded studies are more likely to favor the funders’ products. This has been shown so many times that it’s a given. Exceptions exist, but they are rare.

Q: How much is industry involved?

A: It’s almost impossible to get evidence for that, because you’re not there while the studies are being done.

But some e-mails have been revelatory. For example, in 2015, the New York Times obtained e-mails revealing that Coca-Cola was closely involved with researchers whose studies were aimed at minimizing the effects of sugary drinks on obesity.

Q: What about the recent study claiming that advice to eat less sugar is based on weak research?

A: The authors said that the study’s sponsor—ILSI, the International Life Sciences Institute, which is funded by food and soda companies—had nothing to do with the study. But Candice Choi, an AP reporter, had e-mails showing that the funder had a lot to do with the study. ILSI’s executive director essentially said, “We dreamed up the whole thing.”

Q: Can’t reporters pick up the flaws in industry-funded studies?

A: Even I can have trouble. Sometimes it’s obvious, but sometimes it’s not. And there may be nothing wrong with the way the science is done. It’s how the question was asked, the research was designed, or the results were interpreted that counts.

Or you could have a result that’s equivocal, but you spin it positively. I saw many examples of that in the 156 studies I collected.

Q: Which food industries fund research?

A: It’s hard to think of a food industry that doesn’t. They’ve figured out that if they have a product that looks bad, they can do research to cast doubt on that science and highlight the food’s benefits. This includes sugar, chocolate, Coca-Cola, beef, pork, and dairy.

Q: What about studies on healthier foods?

A: There’s also research on blueberries, almonds, cashews, pecans, avocados, pomegranates. That’s so they can advertise them as superfoods. And it works. It saved the Maine blueberry industry. Someone found out that blueberries had a lot of antioxidants, and they started advertising.

Q: What can people do?

A: Be suspicious. Have more than the usual level of skepticism about a single study. Ask a very simple question: Why did this company pay for this study? What does the company get out of it?

Q: Don’t scientists have to disclose their funding?

A: Most journals require disclosure, but sometimes authors forget. And there are seldom consequences if they do. And even full disclosure doesn’t manage the problem. It lets people think that everything is taken care of.

Worse, there’s a substantial body of research that shows that disclosure may have perverse effects. For some people, seeing the disclosure makes them trust a study more, maybe because they think the authors are being honest.

Q: Aren’t you in favor of disclosure?

A: Absolutely. But we need a unified disclosure statement, so that everybody has to disclose the same thing.

Q: It’s not just about funding a study?

A: Right. Some conflicts are personal. For example, researchers would have to say that they consult for Coca-Cola, have done research in the past for Coca-Cola, have had travel expenses paid by Coca- Cola, or whatever.

And even when it comes to the study, there are gradations. Do the payments include salaries for the investigators, materials, payments to subjects? Or is it something as little as supplying vitamins?

The drug industry literature says that giving doctors a pen and prescription pad is enough to change their prescribing practices, but if you pay for trips or their continuing education or for big presents, it has a stronger effect.

Q: Don’t some people charge that industry funding is only one kind of bias?

A: Yes. They argue that all researchers have intellectual conflicts of interest. That’s true. You wouldn’t do science if you didn’t have intellectual interests.

However, those studies are likely to be repeated by people who have different intellectual interests. That’s why in science, one study does not a conclusion make.

But industry funding only has one purpose, and that is to sell food products. That’s the key difference between any scientist’s biases and industry biases.

Q: How do scientists respond to you?

A: Many are offended. “Are you trying to say that all industry funding is bad?” they ask. No. I’m saying that industry-funded research is more likely to be done for marketing purposes. Enormously more likely.