Nutrition research is deeply biased by food companies. A new book explains why.

Consider the foods you’d like to think of as healthy. Do they include antioxidant-rich chocolate bars? Or immune system-boosting juice? Or maybe “superfoods” like pomegranate granola bars?

Turns out our beliefs about how nutritious these products are is increasingly shaped by scientific research dreamed up and paid for by major food companies and interest groups.

Take chocolate: Over the past 30 years, Nestle, Mars, Barry Callebaut, and Hershey — among the world’s biggest producers of chocolate — have poured millions of dollars into scientific studies and research grants that support cocoa science.

Here at Vox, we examined 100 Mars-funded studies last year and found they overwhelmingly drew glowing conclusions about cocoa and chocolate — promoting everything from chocolate’s heart health benefits to cocoa’s ability to fight disease. This research, and the media hype it inevitably attracts, yielded a clear shift in the public perception of chocolate products that, are also, ahem, full of sugar and calories.

In a new book, Unsavory Truth, Marion Nestle — a nutrition researcher at New York University, writer, and longtime crusader on conflicts of interest in food science — charts dozens of fascinating examples like this, from the likes of Hershey and Coca-Cola, to the Corn Refiners Association and the Royal Hawaiian Macadamia Nut Inc. Through her investigation into how money flows from companies and trade groups to labs, she shows how pervasive the problem is — and why it’s distorting how we think about health.

She also explains why the very notion that any single food might have miraculous health benefits is absurd. “Foods are not drugs,” she writes. “To ask whether one single food has special health benefits defies common sense. We do not eat just one food. We eat many different foods in combinations that differ from day to day; varying our food intake takes care of nutrient needs.”

I talked to Nestle about how the food industry became so influential in academic science, why her food science and nutrition research peers haven’t taken the problem seriously, and how consumers can navigate confusing health claims. Here’s our conversation, edited for length and clarity.

Julia Belluz

You write, “Food science is the food industry.” That’s a strong claim. Can you unpack it?

Marion Nestle

Food science started out in universities as a way to support the food industry. Cornell’s food science department is a good example. In the early 20th century, Cornell University developed departments of dairy, meat, and poultry science in order to support those industries. Faculty did research on the best way to feed animals to maximize their growth.

As the processed food industry became more developed, universities began hiring scientists who could help food companies make and develop new products. So these scientists were part of the food industry — and the food industry supports food science. I now give talks at the Pepsi auditorium at Cornell.

Julia Belluz

It was your informal study of industry-funded food research that got me interested in this issue. You kept finding studies that made almost laughable health claims — ”Concord grape juice, cognitive function, and driving performance,” or ”Walnut ingestion in adults at risk for diabetes” — funded by big grape juice [companies] and walnut growers, respectively.

Marion Nestle

That was part of the genesis of this book. For a year, I collected industry-funded studies with results favorable to the sponsors’ marketing and posted them on my blog. At the end of a year, I had collected 168 industry-funded studies, and 156 of them had favorable results; only 12 did not, despite my begging readers to send me examples.

This was casual and not scientific. But it’s pretty clear that It’s much easier to find industry-funded studies with favorable results than not.

Food companies don’t want to fund studies that won’t help them sell products. So I consider this kind of research marketing, not science. People who do the studies say the conduct of their science is fine, and it well may be. But research on where the bias comes in says the real problem is in the design of the research question — the way the question gets asked — and the interpretation of results. That’s where the influence tends to show up.

Julia Belluz

Yet in the book, you find there’s hardly any systematic studies of these problems. There are only 11 studies on how industry funding has influenced food and beverage research, even though there are thousands of such studies on how drug company money has influenced the practice of medicine. That’s stunning. Why aren’t your nutrition and food science colleagues taking this more seriously?

Marion Nestle

The influence is largely unconscious, and people think industry funding doesn’t affect them, so it just hasn’t come up very much. The one early example I could find was a Center for Science in the Public Interest investigation, with a member of Congress, of food industry influence on academics in 1975. Then I published a commentary in 2001, and the first research article came out in 2003. Altogether, I could only find 11 studies through 2018.

These studies — looking at the results of those funded by a food company and not — seem like they are easy to do, but very few researchers seem interested in addressing or answering such questions. Also, journals seem reluctant to publish those studies, judging from my peer review experience.

Julia Belluz

What do you think is getting in the way of the nutrition community doing something about its conflict of interest problem?

Marion Nestle

If you talk to researchers who take food industry money, they are unaware of the influence of funding and of the large body of literature on the psychology of gifts.

We are human. We like the foods that food industries make — they taste good, they are ubiquitous in our lives, and some of them are iconic. It’s difficult to think of food companies in the same category as cigarette products.

Julia Belluz

You make a strong case in the book that the food industry has borrowed from the tobacco industry when it comes to using science for marketing purposes and avoiding regulation.

Marion Nestle

The tobacco industry, knowing full well that research linked cigarette smoking to lung cancer risk, embarked on a strategy to cast doubt on that research and stave off regulation. Cigarette companies gave gifts to researchers, funded researchers, found ways to support them so they would cast doubt on research suggesting harm and push the uncertainty. The companies worked behind the scenes to convince Congress that there were enough doubts about the research that regulations weren’t needed.

Food is much more complicated than tobacco, but some food trade associations have adopted the “cast doubt” playbook. The American Beverage Association insists that sugar-sweetened beverages have no role in obesity or Type 2 diabetes, for example, despite much suggestive evidence that they do.

Julia Belluz

Do you think food companies should be more heavily regulated?

Marion Nestle

Without question, we need to regulate the marketing of junk food to children. Soda companies shouldn’t be permitted to market sugary beverages — which have sugars and water and nothing else of nutritional value — to kids. For other foods, the situation is more complicated. Foods, even if they’re high in fat, sugar, and salt, have got other kinds of nutrients. So do food companies have a right to make junk foods and market them? Yes, they do, but they should be held to ethical and nutritional standards.

But here’s where politics comes in. All attempts to try and regulate marketing to kids have failed, starting in the late ’70s. Food company executives tell me that marketing to children is their line in the sand. They need kids to pester their parents, become lifetime consumers, and have an emotional attachment to products they loved as kids.

Julia Belluz

This research doesn’t just sow confusion about what we eat — it also confuses people on exercise. You point out the reams of evidence showing how food companies manipulated people’s views about the benefits of exercise.

Marion Nestle

Let me be clear. I greatly favor physical activity as a means to promote health. But for weight, diet matters more.

If you are selling a calorie-laden product, you want to deflect attention from the calories. That was Coca-Cola’s strategy. Coca-Cola funded studies to show that sugar-sweetened beverages and sugar have no effect on diets, weight, or health, and that NHANES — the main survey that correlates sugar-sweetened beverages with diabetes and obesity — has such badly flawed methods that you can ignore what it says.

Julia Belluz

What advice do you have for consumers who are bombarded with and trying to make sense of food and exercise claims? What should they look out for?

Marion Nestle

Please be a bit skeptical. If the title of a study suggests that a food is performing something miraculous, especially for multiple conditions, it’s good to ask who paid for it. No one food can perform miracles, alas. Diets are complicated, people are complicated, lifestyles are complicated.

Other things that should set off red flags: “breakthrough” and my favorite, “Anything you thought you knew about nutrition is wrong.” That’s not how science works.

If you want to eat healthfully, it’s not very hard. Eat your vegetables and fruits, don’t eat too much, and don’t eat a lot of junk food. And, of course, don’t smoke cigarettes, drink too much alcohol, or take drugs.

Variety and processing are the big issues in food. The best advice is to eat as wide a variety of unprocessed foods as possible and to stay active. That’s all it takes to get the nutrients you need and do what you can to stay healthy.

Julia Belluz

In terms of fixing the problem, I’m not that optimistic. Isn’t it how science is done now — the collapse of public funding, reliance on industry money — that’s driving your peers in food and nutrition to accept the money?

Marion Nestle

I see this as a systems issue much more than one of individual choice.

My university encourages public-private partnerships, a euphemism for taking industry funding and getting away with it. Everybody wants the money. The question is how to get it and still maintain ethical standards.

Researchers are under huge societal and personal forces. It’s not just that they want successful careers and that universities want their scientists to be famous. It’s that the system rewards researchers who bring in grants, get published, and do good work — as it should — depending on whether all of that is done ethically.

One question I raise in this book is whether industry-funded research is good work. I see evidence that sometimes it is. But there is also plenty of evidence that industry-funded work can be biased in ways that researchers don’t see or recognize.

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