Every five years, the United States Department of Agriculture (USDA) and the Department of Health and Human Services (HHS) issue the Dietary Guidelines for Americans. The guidelines include updated advice about calorie consumption and food choices to encourage healthy diet and physical activity for Americans. The guidelines are mainly targeted to those above two years of age.
In order to issue these dietary guidelines, the USDA and HHS must first take scientific evidence into account. This is where the Dietary Guidelines Advisory Committee comes in.
Dr. Alice H. Lichtenstein, a professor at Tufts’ Friedman School of Nutrition Science and Policy, was the vice chair on this year’s advisory panel.
“The Dietary Guidelines Advisory Committee was just what the name implies, it was a committee convened to summarize the published evidence on diet and health outcomes for presentation to the secretaries of Health and Human Services and Agriculture,” Dr. Lichtenstein said in an email to the Daily. “Once that task was completed, our committee was disbanded.”
The committee members spent two years looking at scientific evidence and the current guidelines in order to determine what could be kept and what needed to be changed in accordance with advances in the field. They were put into subcommittees which then shared their work with the full committee in order to debate it.
Dr. Miriam Nelson, Dr. Lichtenstein’s colleague at the Friedman School, also served on the Dietary Guidelines Advisory Committee. She led the subcommittee on food safety and sustainability, served on a committee on food and the environment and co-chaired a committee that looked at added sugars. Dr. Nelson said that the DGAC, made up of 14 people, was purely volunteer-based and that its members had to get clearance in order to be a part of it.
“We look at the evidence to help inform what the guidelines will be. The guidelines are the policy that is implemented within federal nutrition assistance programs, such as food stamps, school breakfast and lunch, meals on wheels, senior housing, etc.,” explains Dr. Nelson. “We are the technical team, if you will. We provide guidance and that’s what the report was.”
According to Dr. Nelson, in 1977, when the first guidelines were being developed, the intention behind them was to get Americans to eat slightly less meat.
“Lobbying groups for commodities that produced beef really lobbied against that, and changed it to eat less fat,” Dr. Nelson said. “There were huge ramifications on the dietary guidelines and it was an example of caving into political pressure.”
Today, Nelson believes that political pressure to influence the guidelines still exists to a certain extent, but said that the committee that was formed this year was able to produce findings that weren’t skewed by it.
“Our committee was awesome,” she said. “I believe that we spoke with one voice and there wasn’t a lot of contention. We are not paid by a commodity group; we are academics. We are supposed to look at science and be unbiased.”
This year, the major changes the advisory committee had proposed included changes on the restrictions on fat, cholesterol and added sugar.
“Given the lack of a relationship between total dietary fat and health outcomes, the committee indicated the evidence did not support recommending a target [fat] intake,” explained Dr. Lichtenstein. “With respect to type of fat, the committee indicated that the evidence supports better health outcomes if saturated fat is less than 10 percent of calories, when the saturated fat is replaced with unsaturated fat, particularly polyunsaturated fat, and not refined carbohydrate.”
Dr. Liechtenstein said that the severity of cholesterol restrictions was also reduced.
“With regard to dietary cholesterol the committee concluded that within the context of current intakes there no longer needed to be a targeted upper limit,” she said.
The negative effects of large quantities of added sugars were confirmed: Dr. Nelson explained that the committee is now recommending that no more than 10 percent of calories should come from added sugars.
The committee also looked at evidence on the effects of coffee and caffeine, which produced some interesting findings.
“We saw that coffee, not caffeine, is quite health promoting,” Dr. Nelson said. “It may reduce risk of heart disease, type 2 diabetes, some cancers and potentially Parkinson’s disease.”
Before giving college students a chance to rejoice, however, Dr. Nelson was quick to clarify that moderate amounts of coffee, not five cups or large quantities, would prove beneficial.
For the very first time, the committee’s recommendations also take into account the impact of food production, processing and consumption on environmental sustainability. Part D, Chapter 5 of the report reads: “The environmental impact of food production is considerable and if natural resources such as land, water and energy are not conserved and managed optimally, they will be strained and potentially lost.” Among its recommendations are linking sustainability with healthy diets, increasing demand for sustainable food and minimizing waste.
Some say that the committee overstepped its bounds in this aspect of the report. According to an article published on theblaze.com, Agriculture Committee Chairman Mike Conaway (R-Texas) said of the recommendations, “members of the Dietary Guidelines Advisory Committee greatly exceeded their scope.”
Dr. Lichtenstein said that along with the recommendations from the advisory committee, the USDA and HSS also look at public comments like these in order to inform their final decisions on guidelines.
“Ultimately, it is important that dietary recommendations can be adapted to personal, cultural and ethnic preferences,” she said.
The advisory panel this year consisted of three members from Tufts University, an impressive number considering no other university had the same representation. When asked about her reason to be a part of the panel, Dr. Nelson, who is also the associate dean of the Jonathan M. Tisch College of Citizenship and Public Service, saw her service as her way of giving back.
“As a professional in the world of food and public health, guidelines have a huge impact on people and health and so it’s an honor,” Dr. Nelson said. “I care deeply about the public’s health and so this is a way in terms of public service to give back.”