March 3, 2016
Every five years USDA and HHS hammer out a revised set of recommendations for how Americans should eat. The process, resulting in the Dietary Guidelines, is supposed to be transparent, accessible and systematic. But there is a black box in the process, says Dr. Frank Hu.
Dr. Hu is a member of the most recent Dietary Guidelines Advisory Committee (DGAC) and a professor on the faculty of both the Harvard School of Public Health and Harvard Medical School and Brigham and Women’s Hospital. On February 26, he offered some insight into the process at the invitation of the Johns Hopkins Center for a Livable Future, addressing students, faculty and staff at the Bloomberg School.
The US Dietary Guidelines (DG) are jointly released by Health and Human Services (HHS) and USDA every five years. The most recent process began three years in advance of the scheduled release with the formation of the DGAC. This committee of 15 nationally recognized experts – medical researchers, academics and practitioners – met regularly over the next two years to pour over the available literature on nutrition science. Every meeting was recorded, and open public meetings were held with opportunities for input. Public comments were solicited throughout the process. The DGAC work was segmented into five sub-committees and four workgroups (Sodium, Saturated Fat, Added Sugar and Physical Activity), and each committee member served on two subcommittees and two workgroups.
Sustainability a new focus
This was the first time that a Sustainability Subcommittee was a part of the DGAC. According to Dr. Hu, the Subcommittee put together a comprehensive report on the environmental impact of diet, and evidence for it has grown even since the DGAC disbanded. The research strongly suggests that a diet that includes less meat and more plant-based foods has a smaller impact on the environment, and there is ample evidence that greenhouse gas emissions are highest from ruminant animals such as cows and sheep. And the amount of water involved in beef production far outpaces any other source of food that is currently being measured, requiring over 300 liters of water to produce a 3-ounce portion of beef (for reference, a Big Mac contains 3.2 ounces of beef).
In addition to sustainability, the DGAC looked at other research that underlines the importance of reducing red meat consumption for the the health of people and the environment, and after two years of nearly full-time work, the DGAC released its 600-page Advisory Report in February 2015 synthesizing scientific evidence and outlining recommendations for the development of the DG.
Dr. Hu referred to two meta-analyses published by the American Journal of Clinical Nutrition  and Archives of Internal Medicine  in 2011 linking both processed and unprocessed meat intake to morbidity (Type II Diabetes) and mortality. The DGAC report also included a strong look at research on fats and oils. The report concluded that the burning issue is not necessarily how much fat is consumed, but what type of fat. Saturated fat is still associated with health risks, and what you replace it with really counts. In fact, for the first time, there is no upper limit recommended for total fat or cholesterol, but the report recommends keeping saturated fat intake at kept less than 10 percent of calories. (See below for more highlights and recommendations from the DG report*.)
From here, the DGAC was disbanded, and the two-year process along with its report was handed over to USDA. Also at this point, the public was once again given opportunity to respond with written comments and oral testimony at another public meeting. And comments were received—over 30,000 of them! The Advisory Report attracted flowing praise and harsh criticism that ranged from applauding them on holding true to science to stepping out of scope by addressing sustainability as it relates to diet.
The USDA then took one year to write the DG based on the Advisory Report and the comments that had been received. Dr. Hu pointed out that the transparency of the DG process was largely removed during this period.
So… what came out of the other end of the black box? A few things that Dr. Hu highlighted:
- In the final DG, there is no mention of red meat consumption. Although saturated fat and protein consumption are addressed, the specifics are buried.
- Sustainability is not mentioned.
- There are not references to soda consumption, just recommendations for added sugar.
- Overall, the DG are not clearly reflective on the the Report of the DGAC.
The DGAC spent two years poring over the science and working to come up with clear, science-based recommendations but was not involved in the final process of writing the Dietary Guidelines. There is a black box in which only USDA knows what goes on, but the process is subject to levels of interference in the year that it is out of the hands of the AC. Congress has appropriated $1 million to review the process, but which part of the process will it be? The open, transparent process of the DGAC or the black box of USDA?
*Other highlights from the 2015 DGAC Report:
- An emphasis on healthier eating patterns, rather than single nutrients. These are Healthy U.S.-style Pattern, the Healthy Mediterranean-style Pattern, or the Healthy Vegetarian Pattern. In other words, what you replace a nutrient with makes a difference.
- No upper limit of total fat or cholesterol was given. Types of fat are emphasized in the report, including a recommendation to limit saturated fat to 10 percent of calories .
- The environment and sustainability was considered for the first time.
- Added sugar was given a limit (<10 percent of calories).
- Recommended sodium limit remained the same.
- Health benefits of coffee were highlighted.
- Optimizing nutrition and environmental impacts of farm-raised seafood were addressed.
“The overall body of evidence examined by the 2015 DGAC identifies that a healthy dietary pattern is higher in vegetables, fruits, whole grains, low- or non-fat dairy, seafood, legumes, and nuts; moderate in alcohol (among adults); lower in red and processed meats; and low in sugar-sweetened foods and drinks and refined grains.”
 Am J Clin Nutr October 2011 vol. 94 no. 4 1088-1096
 Arch Intern Med. 2012;172(7):555-563. doi:10.1001/archinternmed.2011.2287
Photo of Frank Hu: D. Chris Stevens, 2016; Image/slide by Frank Hu.