The BMJ Stands by Study Questioning Scientific Validity of U.S. Dietary Guidelines
2015 peer-reviewed article by Nina Teicholz had been target of an unprecedented retraction effort
December 3, 2016
New York, NY — In a victory for science, The BMJ (formerly The British Medical Journal) today stood in support of a peer-reviewed study it published in September 2015 by investigative journalist Nina Teicholz, which concluded that that the current U.S. Dietary Guidelines for Americans (DGAs) are founded on weak scientific evidence and do not reflect the best and most current science. The article had been the subject of intense scrutiny by the members of the 2015 DGA expert committee (DGAC) as well as advocacy and research groups that have long championed a diet high in carbohydrates and low in saturated fats, as the DGAs have recommended for more than 35 years.
“We stand by Teicholz’s article with its important critique of the [DGA] advisory committee’s processes for reviewing the evidence, and we echo her conclusion: ‘Given the ever increasing toll of obesity, diabetes, and heart disease, and the failure of existing strategies to make inroads in fighting these diseases, there is an urgent need to provide nutritional advice based on sound science,’” said Dr. Fiona Godlee, Editor-in-Chief of The BMJ, in a press release.
Teicholz has become a prominent critic of conventional nutrition, following the decade-plus of research she conducted on nutrition science for her book The Big Fat Surprise, an international and New York Times best-seller, and named the #1 science book of 2014 by The Economist.
Today’s announcement by The BMJ that Teicholz’s assertions are scientifically sound validates the main findings of the study, including revelations that the DGAC did not follow the USDA’s standard review process on a majority of topics, that the DGAC did not use properly systematic methods in a number of ways throughout its report, that a number of DGAC recommendations, including the new vegetarian “Dietary Pattern,” are based on evidence that the DGAC judged to be “inconclusive,” and that the government’s recommended diets are generally based on a “minuscule quantity of rigorous evidence that only marginally supports claims that these diets can promote better health than alternatives.” The article also explained that these lapses may have been due to different kinds of bias: financial conflicts of interest, outside agendas, and a desire to confirm existing advice.
While members of the DGAC and advocacy groups had attempted to refute several aspects of the article, none of the aforementioned key findings were found to be in error.
Because the DGAs have long been considered the global “gold standard,” informing nutrition advice dispensed by health professionals across the nation as well as the government’s feeding assistance programs, including the National School Lunch program, which altogether serve meals consumed by one in four Americans each month, Teicholz’s critique has far-reaching implications for not only the U.S., but also for professional societies and governments around the world. Her article makes clear that the standard low-fat, high-carbohydrate, government-issued diet that we have followed for decades is not based on rigorous science and is wholly ineffective in preventing nutrition-related diseases.
“I hope that The BMJ’s decision to stand by my article will close the book on this prolonged retraction effort, which attempted to silence science and stifle debate on this important topic,” says Teicholz. “My hope has always been that the information in this article can be used to improve the Guidelines, so that they can better reflect the science and ultimately, do a better job in fighting the epidemics of obesity, diabetes, and heart disease–which afflict a majority of Americans.”
Some of the successfully refuted points of contention from the original study include:
- Evidence of a “strong” link between saturated fats and heart disease was not clearly supported by the evidence cited by the DGAC.Although advice to cut back on saturated fats has long been a pillar of the DGAs, no expert DGA committee has ever directly reviewed the enormous body of rigorous government-funded evidence, testing more than 25,000 people, on this hypothesis.
- The DGAC ignored a large body of scientific literature on low-carbohydrate diets(including several “long term” trials of 2-years duration) demonstrating that these diets are safe and highly effective for combatting obesity, diabetes, and heart disease.
- The DGA’s three recommended “Dietary Patterns” are supported by only a “miniscule quantity of rigorous evidence” that they can fight disease. The reviews conducted by the USDA’s Nutrition Evidence Library found only “limited” or “insufficient” evidence that the recommended diets could combat diabetes and only “moderate” evidence that the diets can help people lose weight. And the “vegetarian diet,” introduced by the 2015 DGAC as a new addition to its three “Dietary Patterns” is backed by only “limited” evidence for preventing disease, which is the lowest rank of evidence assigned for available data.
- The 2015 DGAC conducted a number of its scientific reviews in ways that were not systematic.This allowed for the potential introduction of bias (e.g., cherry-picking of the evidence) or outside industry influence.
For other important findings, on such topics as salt and meat, please see Teicholz’s comment on The BMJ outcome, here.
Members of the academic, scientific, and journalism community alike stood in support of the study and applauded today’s announcement by The BMJ.
“The [Dietary Guidelines] committee seems to be completely dissociated from the top level scientific community, and unaware of the most updated evidence,” said Arne Astrup, Head of Department of Nutrition at University of Copenhagen in reaction to the original study.
“This paper raises serious questions about how the dietary guidelines conducts its reviews, especially its systematic reviews, and whether they are based on a comprehensive review of the science,” said Cheryl Achterberg, Dean of the College of Education and Human Ecology at The Ohio State University and a former DGAC member. “These criticisms have now been confirmed by outside reviewers. For future guidelines, as well as for the health of the nation, we need to consider these points and move towards reforming the dietary guidelines process.”
“I congratulate The BMJ on withstanding pressure to retract this article,” added Richard Smith, the former editor-in-chief of The BMJ. “There is an ugly tendency these days for powerful groups to call for retraction of any article they don’t like. The BMJ has stood up for science on a crucial subject that affects everybody.”