On Nutrition

It seems as if every time I turn around, there’s a new book promising huge health benefits. Unfortunately many of these books make health claims and dietary recommendations that aren’t backed up by scientific evidence — even when the authors say that they’re science-based. So if you don’t have a nutrition-science degree, how do you separate the wheat from the chaff? Red Pen Reviews (redpenreviews.org) is a good place to start.

“Outrageous health claims are a time-honored tradition in this country,” said Red Pen Reviews founder Stephan Guyenet, Ph.D. “I don’t know if it’s worse today than it used to be, but it’s currently an exploding volcano of nonsense.” He calls the health and nutrition publishing world “a minefield” for readers. “One book says carbs are the devil, the next says fat. A recent popular book even says that vegetables are killing us. All of them claim to be supported by scientific evidence. Like many people, I’m frustrated by these competing claims and I want to know who’s right, or at least who is making scientifically persuasive arguments and citing evidence accurately.”

Guyenet said most book reviews don’t provide helpful guidance for a few reasons — the reviewers usually aren’t nutrition-science experts, rarely fact-check claims, and write about whatever aspect of the book catches their interest. “The public needs a resource to help evaluate the information quality of health and nutrition books,” he said, adding that the publishing industry needs better incentive to publish factually accurate books. “Ultimately, better information means better health for us all.”

Guyenet and his team of reviewers all have advanced degrees in nutritional science or a closely related field — Guyenet earned his doctorate in neuroscience from the University of Washington. They score each book on scientific accuracy, accuracy of its references (a book may cite research studies that don’t actually support its claims), and the healthfulness of what the book is promoting.

“What we have in common is that we are all consumers of these types of books — I read them in my free time, in part because I’m hoping to learn something new,” said Red Pen reviewer Mario Kratz, Ph.D., a faculty member and researcher at Fred Hutchinson Cancer Research Center and the University of Washington. Kratz recently reviewed Steven Gundry’s “The Plant Paradox,” which claims that lectins, a type of molecule found in certain plant foods (including grains, legumes, fruit, and nightshade and cucumber-family vegetables) and some types of dairy cause obesity and numerous chronic diseases. “The author claims repeatedly that it’s based on scientific evidence, but it’s not,” Kratz said. “The degree to which people think they can fool everyone is apparently without limits.”

Misinformation aside, Kratz said that books like “The Plant Paradox” can get in the way of actual research. For example, he said if he applied for a grant to study lectins and investigate whether they have an effect on health, the application would likely be rejected because lectins are now viewed as a fad. “There’s no accountability whatsoever. People can write whatever they want, and apparently publishers will publish it,” he said. “We have a responsibility to help consumers differentiate between what is and isn’t based on science and ultimately help them make sense of these books if they choose to read them.”


Guyenet said when he wrote his 2017 book “The Hungry Brain,” he realized that no one fact-checks health and nutrition books. “I chose to have my book reviewed by experts, but that was completely voluntary,” he said. “There is no filter in place to protect consumers from inaccurate and potentially harmful health information. There is no incentive to be accurate, and in fact there’s an incentive to be inaccurate because unusual or exaggerated claims get more attention.”

Although many nutrition and health professionals read Red Pen’s reviews, the reviews are designed to be useful to anyone who is interested in health and nutrition books. At the top of each review page are at-a-glance color-coded percentage bars rating the book in each of the three categories surveyed. If you want more information, you can scroll down to the review’s summary, and if you want even more detail, you can keep scrolling to read the full review. Because each book is scored using the same scale, as the number of reviews grows, readers will be able to compare scores between books to find the best book on a specific topic.

Books reviewed so far include “Grain Brain,” “The Bulletproof Diet” and “The Longevity Diet.” Guyenet said he anticipates publishing about one review per month, focusing on the most popular newly published health and nutrition books, as well some influential classics. Future plans include expanding the reviews to cover topics such as medicine and exercise science, which will require recruiting expert reviewers in those areas, and possibly offering reviews in different languages. “We want to become the default resource for people looking to evaluate the books they read or are thinking about buying,” he said, “and we want authors and publishers to understand that the success of their books will now depend on how factually accurate they are.”

Along those lines, Guyenet points out that the aim isn’t simply to critique, it’s also to support authors. “We’ve published our full review method on our website so authors can guide their writing in a more evidence-based direction before we even see their book.”