Commentary: When food lists collide: Should we eat kale or not?

Issue Date: April 10, 2019
By Dave Kranz
Dave Kranz
Grocery shoppers, restaurant customers, farmers and ranchers find themselves buffeted by conflicting and contradictory advice about what to eat, what to grow and how to grow it. For example, reports issued by interest groups during the past month both condemned and praised kale.
Photo/Rick Quinn

Does it seem that everyone wants to tell you what to eat—or what not to eat?

Nary a week goes by but some blue-ribbon commission or scientific panel or interest group leans over your shoulder at the dinner table to ask, "Are you really going to eat that? Don't you know that (food X) is laced with pesticides/contributes to global warming/clogs your arteries, etc.?"

Of course, the people behind these reports don't literally come to your dining room. Instead, they typically infiltrate through the media: a news story on TV, a blog posting on the internet, a magazine article noticed by a family member.

To garner media attention, these lists often carry click-bait titles such as "The Dirty Dozen" or "50 Foods for Healthier People and a Healthier Planet." Those aren't hypothetical titles—they're real examples of reports that flashed across the media landscape in recent weeks.

Each of the reports had a political motivation cloaked in dietary guidance and, as can happen, the two reports provided contradictory advice about certain foods. In this case, two foods in particular found themselves condemned in one report and praised in the other: kale and spinach.

An anti-pesticide group issues its Dirty Dozen list each year, comprised of foods it claims to be the most "contaminated" with pesticide residue. It typically bases its findings on data from the U.S. Department of Agriculture Pesticide Data Program.

For its part, the USDA report says "more than 99 percent of the samples tested had pesticide residues well below benchmark levels established by the Environmental Protection Agency." But if you're an anti-pesticide group, and your goal is to frighten people, any detection—no matter how tiny or insignificant—equals "contamination."

And because kale samples contained pesticide residues, the anti-pesticide group plopped it onto its Dirty Dozen list, along with spinach and other produce crops, and highlighted kale in its annual report. The media, of course, bit, with headlines such as "Kale is one of the most contaminated vegetables you can buy" (Time) and "New produce guide shows eating kale is a lot dirtier than you think" (San Diego Union-Tribune).

The Alliance for Food and Farming, a Watsonville-based organization that works to deliver credible information about produce safety, has had some success through the years in countering the Dirty Dozen report. It estimates a woman could eat 18,615 servings of kale a day and still not have any health effects from the residues detected in the crop.

But the "kale is contaminated" headlines continued to swirl. Shortly thereafter, a wildlife organization and a multinational food company issued their report on the 50 foods they believe people should eat.

"In a world cluttered with advice and pressure around what not to eat, we want to provide people with more food choices to empower positive change," the report said—but of course went on in the next sentence to imply that people should avoid animal-based foods while working to broaden their diets.

The report says reliance on animal-based protein requires more water and land, and generates more greenhouse gases, than plant production. There's been a lot of talk in the media about livestock and climate change—and researchers such as Frank Mitloehner at UC Davis have provided important perspective by showing that foregoing meat isn't the environmental solution some believe and could ultimately have harmful nutritional consequences.

But, back to kale and spinach. They turn out to be two of the 50 crops the report from the wildlife group and the food company says people should eat. The report describes kale as a hardy plant with "lushly dark leaves," "packed with vitamins" and a good source of manganese and copper. For its part, spinach earns praise for its "many important nutrients" and its suitability for year-round cultivation.

Other crops listed in this "should eat" report include California-grown staples such as walnuts and dry beans, and crops being grown here on a smaller scale such as nopales, wild rice and moringa. No doubt, a number of the other crops are also being tried by creative California farmers, seeking to find and develop new markets.

That's what farmers do. They seek to grow what people want to eat. In California, farmers have the ability unlike anywhere else to provide the full variety of crops and commodities that our state's rich range of climates, soils and knowledge can produce.

Like shoppers and restaurant patrons, farmers and ranchers can be buffeted by conflicting and contradictory advice about what to grow and how to grow it. But California agriculture succeeds by adapting.

In 2007, California farmers grew 2,755 acres of kale. By 2017, acreage had more than doubled, to 7,677. Whether either the Dirty Dozen report or the "50 foods" report directly influences acreage trends in the next year or two seems unlikely. But if people want to eat it, California farmers and ranchers will try to grow it, and do so in the most responsible way.

(Dave Kranz manages the California Farm Bureau Federation Communications/News Division and edits Ag Alert. He may be reached at

Permission for use is granted, however, credit must be made to the California Farm Bureau Federation when reprinting this item.

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