In an attempt to avoid potential biases in the Dietary Guidelines Advisory Committee (DGAC) recommendations the United States Department of Agriculture (USDA) established the Nutrition Evidence Library (NEL) in 2006, with the specific intent of increasing the integrity of nutrition policymaking. The beauty of the NEL is that it created a system to evaluate scientific research using state-of-the-art methodology with a strict hierarchy of evidence and a rigorous transparent grading process. It was disappointing to see the 2015 DGAC use the NEL to address only 27 percent of its science-based research questions.

When I served on the DGAC in 2010, the committee was the first to leverage the NEL which we used to address the majority of our research questions. As such, our recommendations were mostly adopted by the USDA and the Department of Health and Human Services (DHHS) with little controversy. There was no need for Congressional interjection and limited public debate on the report we issued. In fact, in 2010 only about 1,200 comments were submitted during the public comment period.


Fast forward 5 years and you have the most politically charged DGAC report to date. How can the 2015 report be so explosive and controversial if the recommendations come from a renowned scientific panel of experts? The reason is simple.  The committee relied on an approach that departed assessments of individual randomized control trials (RCTs) and epidemiological data.  In addition, the panel made recommendations in areas which were both out its scope and expertise which in turn led to conclusions hard to justify.  

Instead of relying on the tried and true NEL, the 2015 DGAC leaned heavily on previously published systematic reviews and meta-analyses which use multiple individual research studies and synthesize them. Not only is this approach still in its infancy in the nutrition field, but it continues to be contested in the scientific community because it is more subjective than the NEL approach.  Unlike the NEL, this approach has no standardized criteria to evaluate findings. Additionally, it increases the risk for inheriting pre-existing conclusions that may be prone to biases and subjective decisions of the authors. While perhaps well intended, depending on inclusion and exclusion measures, conclusions can be blatantly premediated or previously subjected to such a bias through this method.  For these reasons the 2010 DGAC opted not to use this type of methodology at all. From that perspective, it’s no wonder the 2015 report is being held to a new level of scrutiny from the public, Congress, and many within the scientific community. In fact, the 2015 recommendations garnered over 29,000 public comments, an unprecedented amount of interest for this type of scientific report.  

There is no room for the amount of subjectivity used by the 2015 DGAC in this process. As it is, consumers face confusing, conflicting, and increasingly inaccurate information about nutrition every day. The federal government should be in the business of making things less confusing for consumers, not more. After all isn’t that was this process was intended to do? Unfortunately, the 2015 DGAC recommendations fall short and instead offer up complicated and perplexing policy recommendations such as taxes or bans on certain foods and beverages, for instance, which do little to inform general consumers on how to create better diets.

While the 2015 panel overstepped its mandated boundaries, it’s worth noting that the DGAC process itself is broken and is in serious need of reform. While medical doctors rely on real time data to determine its conclusions, nutrition experts have and continue to rely on old data which makes nutrition policymaking a real challenge. In absence of real-time data, the strongest available science must prevail. Next, the formation of the DGAC panel is subjective, lacks well-rounded diverse representation, and is in dire need of greater transparency.  For instance, I am only the second food scientist to ever serve on a DGAC since its enactment.  Last, the DGAC needs more accountability. In 2010, the panel I served on posed more than 60 research questions to the 2015 DGAC, to date, every one of those questions remains unanswered.

While it’s discouraging to see the dietary guidelines process become politicized, Congress should be commended for putting proposals forward that would get the 2015 DGAC back in line with it intended purpose. It’s time to get back to the basics and make recommendations that are clear and achievable for the average American.  And we can only achieve that when scientists rely on the strongest and best available evidence.

Clemens is an adjunct professor of Pharmacology & Pharmaceutical Sciences at the USC School of Pharmacy, International Center for Regulatory Science.