Congress will hold a hearing this morning that will discuss the contentious recommendations made by the Dietary Guidelines Advisory Committee (DGAC). The hearing, which will see both USDA secretary Tom Vilsack and HHS secretary Sylvia Burwell appear before the House Committee on Agriculture, is an important one, as DGAC recommendations are used to inform national dietary policies—including everything from food labels to school lunches.
As I described last year, the DGAC is a federally mandated group made up of fifteen academics, culled from fields like nutrition, public health, and medicine. The mission of the DGAC, which has met every five years for the past 25 years, is to come up with recommendations "to help people choose an overall healthy diet that works for them." Much of the DGAC's work has been intrusive and meddlesome.
For example, I previously blasted the DGAC's work for suggesting the federal government send scolding text messages to obese Americans and its call for what I termed "a steady diet of taxes and other intrusive policy recommendations."
I'm hardly the only critic of the DGAC's work. Earlier this year, for example, I interviewed a prominent DGAC critic, Dr. Edward Archer, who argues, in a Mayo Clinic Proceedings article, that the DGAC is the latest federal government construct to present "anecdotal evidence as science."
Some or all of that may sound innocuous. But today's committee hearing comes in the wake of a recent article in the British Medical Journal by journalist and author Nina Teicholz that is highly critical of the DGAC's findings. Teicholz, author of the award-winning book The Big Fat Surprise, argues that the DGAC's conclusions are based on scant evidence, and that the committee willfully ignored evidence that might contradict those conclusions. "The omissions seem to suggest a reluctance by the committee behind the report to consider any evidence that contradicts the last 35 years of nutritional advice," Teicholz writes in the BMJ.
Teicholz's article has gotten lots of press and has found equally vocal supporters and detractors. This week, I asked Teicholz about her BMJ article, and why it's proven so controversial. My questions and her responses (both sent by email) are below.
Reason: Tell me about The Big Fat Surprise. Why did you write it? What is your argument? Who loved it? Who hated it? Why?
Nina Teicholz: I did not intend to write this book. In 2003, Gourmet magazine assigned me a story on trans fats, which got a lot of attention and which eventually led to a book contract—on trans fats. Diving into the subject of dietary fat, which is the subject that our nutrition recommendations have most obsessed about—good fat, bad fat, low-fat, non-fat—made me realize that there was a much bigger story, on how our nutrition policy had seemingly gotten it wrong on all fats. That was 10 years ago. I spent nearly a decade researching the topic and wrote a book on the history, politics, and science of dietary fat. My book makes many discoveries about different diets and fats, about vegetable oils, trans fats, the Mediterranean diet (olive oil), and tropical oils, but its main argument is this: that the hypothesis that saturated fats cause heart disease has always been based on weak, inconclusive science and does not hold up. This is part of the argument that the fat overall has been unfairly demonized and has been a distraction from the real cause of nutrition-related diseases. When I began my book, I had been mostly vegetarian for more than two decades. It was quite a personal transformation.
(Note: the book has been called "pro-meat," but this is inaccurate. The book does not make an argument for meat. It makes an argument for saturated fats, and meat is just one of the foods that includes this type of fat. Dairy, eggs, coconut oil and palm oil are others, and it's important to note that all these foods contain a mixture of fats, not just saturated.)
I was lucky in that many people loved my book. It was named a *Best Book* of 2014 by the Economist, the Wall Street Journal, Forbes, Mother Jones, Library Journal, and Kirkus Reviews. It got strong reviews in the British Medical Journal and the American Journal of Clinical Nutrition. It served to inform quite a few magazine cover stories worldwide, including a now-iconic one featuring a picture of a butter curl for TIME. The subject matter was ground-breaking, and I think people loved it, too, because the book explained why they didn't need to feel guilty about eating these foods that had long been a part of their cultures—a Swedish grandmother's recipe with butter, for instance. Also the foods containing these long-forbidden fats are delicious, so many people tell me that it's been a great pleasure to welcome them, guilt-free, back into their lives. I also get a lot of emails from people telling me that after a lifetime of struggling with their weight, they effortlessly lost it after reading my book and switching to a higher-fat diet.
The people who hated the book were the institutions and people who had invested themselves in the idea that saturated fats cause heart disease, which is pretty much a clean sweep of the establishment. Most notably, this includes the American Heart Association and scientists close to the Dietary Guidelines process. These researchers have launched no end of attacks against me, mainly ad hominem and personal in nature. Strikingly, there has been no serious scientific critique of my book by any serious scientist.
Reason: Your recent article on the DGAC in the British Medical Journal has caused quite a stir. Tell me about the piece and about the positive and negative feedback it's received.
NT: The BMJ piece was based on an enormous effort to analyze all the science in the DGAC report. On all the key issues, I went back and reviewed all the clinical trials they cited to see if they supported the report's conclusions. All this research was done in time to submit as a public comment to the DGA by May 8th. The entire report is available at www.forbetterdietaryguidelines.com (warning—it's long!). From that body of research, I wrote up the BMJ article. What I found was that on many key issues, the DGAC did not use a systematic methodology for reviewing the scientific literature . This is important, because methodology exists in order to prevent bias, of whatever kind, from entering into the selection and evaluation of evidence. In fact, USDA in 2010 implemented a new rigorous "checklist" system to improve the methodology for the DGAs, and on quite a few key topics, the 2015 DGAC simply didn't follow it. So that opens up the report to the possibility of bias, which I think can be observed.
There's been an angry response, which could only be expected. CSPI and the entire DGAC submitted critiques on the BMJ website. I submitted a response to those last week which BMJ plans to post soon. Meanwhile, my response to CSPI was published here. There have also been a few aggressively one-sided articles in The Verge, by a reporter who has never before covered nutrition science and seems to be writing as a spokesperson for some of the advisory committee members. And it's notable that all the mainstream coverage, in Time, Newsweek, CNN, Yahoo Health, Medpage, etc., has been balanced or positive. For instance, one can compare the Verge reporter's work to coverage in Cardiobrief, which cites Arne Astrup, professor, University of Copenhagen, saying, "The committee seems to be completely dissociated from the top level scientific community, and unaware of the most updated evidence."
What is disappointing to me is how some prominent nutrition voices have responded with ad hominem attacks rather than reckoning with any of the serious issues I raise. For instance, I've been accused of doing all this work only to promote book sales. This is a hypocritical critique, leveled by experts who themselves have popular diet books to sell: Marion Nestle has seven, David Katz has seven, and 3 members of the DGAC have books: Miriam Nelson, Barbara Millen, and Alice Lichtenstein have all authored popular diet books. My own view is that it's fine to write a book and also work as an academic or a journalist: a book is a representation of one's knowledge. Of course it creates a bias in favor of preserving one's existing views, yet so do journal articles and non-popular books. We all have a bias in favor of preserving our published views and not to have to retract them, so it's unfair to single me out. Also, I believe it's fair to say that a diet book is more of a commercial venture and therefore would open up an author to the critique that one is 'only out to sell books.' My book is not a diet book but a serious non-fiction effort covering history, politics, and science, with thousands of footnotes.
Another criticism of me are that I am not an expert but a journalist. My response to that is on my website, here.
But these and other criticisms seem to be diversionary tactics. The main point here is not about my book. It's about the scientific issues that I raise—the serious problems with the science and methodology of the DGAC report. Many serious researchers are concerned about these issues, and they need to be addressed. To date, they have not been.
Reason: The BMJ published two corrections of your article. What are they? And do they invalidate your conclusions in any way?
NT: These were not corrections but clarifications. The amplified attention to these clarifications was clearly the result of the overall heightened scrutiny of the article generally, but they were normal and in no way changed any of the conclusions of the article.
I wrote a further clarification about the "lean meat" point here.
Reason: Prof. Marion Nestle writes, in a critique of your book, that her "hypothesis (note: hypothesis) is that for people who balance calorie intake with expenditure, the type of fat—or carbohydrate—matters much less than it does for people who overeat calories." Your argument is that the type of calories do matter, and that fat has been wrongly vilified. We have dueling hypotheses here. Which hypothesis does the DGAC's recommendations reflect? And why is that important?
NT: Marion Nestle's argument that total calories are the most important factor in driving weight gain or loss has been the predominant one for decades, but it's not supported by the current scientific evidence. In nearly all the head-to-head diet trials a diet low in carb achieves greater weight loss than one low in fat at the 6 months mark, after which adherence to any diet tends to decline. However, there's also some evidence from a meta-analysis of studies where carbs are strictly controlled, that this diet outperforms the low-fat diet in the long run as well. Moreover, in all these studies, the low-carb diet wins even though calories are typically not restricted. Subjects are told to go on this diet and eat until full—not to count calories. So, in effect, calories are not the controlling factor here. The differing effects of these diets must instead be due to the different composition of the calories—whether from fat, protein or carbs. Evidence is mounting[,] for example, that protein and fat are uniquely satiating, so that people don't "overeat" as much on those foods. There is also a great deal of evidence to show that carbohydrates are uniquely effective at triggering the release of insulin, which contributes to fat deposition and the exposure to which over time leads to Type 2 diabetes. So the hypothesis that all calories are metabolized in the same way simply doesn't reflect the current scientific evidence. Moreover, the question any single person wants to know is: is what is the best strategy for me to lose weight? Whatever you think about calories, the evidence from diet trials shows that your chances for losing weight will be higher if you start by restricting carbs rather than fat.
Reason: Can a person believe your faith in fat is misplaced and still believe the DGAC's own faith in the so-called Mediterranean diet is misplaced? Why?
NT: The DGAC's version of the Mediterranean diet is modeled, in the tables of the DGAC report, to be low in fat—33% of calories as fat. By contrast, the Mediterranean diet that has shown to be successful in clinical trials is more than 40% fat. It also typically contains more meat and eggs than the DGAC version. In fact, the success of the Mediterranean diet in these experiments may solely be due to its greater fat content, since in clinical trials, the control to which it is compared is the conventional low-fat diet. In any case, the higher-fat Mediterranean diet in these experiments does not closely resemble the DGAC-recommended low-fat Mediterranean diet. So the conclusion is: the higher-fat version of the Mediterranean diet is the one that has been shown to be better for health.
Reason: I wrote a piece this summer on the DGAC featuring comments from Dr. Edward Archer. How, if at all, do your criticisms of the DGAC report line up with those made by Dr. Archer?
NT: Dr. Archer mad[e] the important observation that much of the data upon which the DGAC reports are based is inconclusive. My DGAC report expands on this point.
Reason: What should the government's role be in terms of recommending an ideal diet?
NT: I think the government should "first, do no harm." On subjects for which conclusive evidence does not yet exist, it should simply inform rather than advise. We have seen so many reversals in recent years—on total fat, dietary cholesterol, and more—that the public is losing confidence in the Guidelines. Moreover, the government should not be experimenting on the public health with various ideas based on inconclusive science. So I believe that the government should first, back out of the low-fat, high-carb diet that it started recommending in 1980, and then it should do a rigorous review of the science for its other recommendations.