Leading experts debate the role that science—and politics—played in the new 2015 Dietary Guidelines+ READ ARTICLE
On Thursday, the government released the 2015 Dietary Guidelines for Americans. From school lunch menus and public nutrition programs to food labels and medical research grants, these standards will inform dozens of government health programs and policies. They’ll also play a part in determining the foods America produces, buys, and eats.
The guidelines are “grounded in the most current scientific evidence” and are meant to help people “make healthy food and beverage choices,” according to the government agencies that produced them. But a number of leading nutrition experts—including some tasked by the government to advise it on the latest research—say the guidelines are influenced too much by food manufacturers, food producers, and special interest groups. As a result, many experts say some of the government’s diet advice continues to promulgate out-of-date research from years past.
While many doctors and scientists have applauded some of the new guidelines—especially the recommendation to eat less added sugar—they also say some of the guidelines, which received mixed reviews, are out of step with the latest medical research, particularly when it comes to the consumption of red and processed meat.
“It’s upsetting to see cycles of misinformation coming back over and over again,” says Dr. David Heber, founding director of the University of California, Los Angeles, Center for Human Nutrition. “The public has been confused and will remain confused by these guidelines.”
The guidelines are issued by the U.S. Departments of Agriculture (USDA)—the agency in charge of strengthening America’s farming, food and agriculture industries—and Health and Human Services (HHS). USDA and HHS base the final guidelines at least in part on a report from the Dietary Guidelines Advisory Committee, which is made up of experts in the fields of health and nutrition. The Advisory Committee bases its recommendations on thousands of pages of published research, and their report is open to public comment.
But while the final guidelines carry forward some of the recommendations outlined in the Advisory Committee’s report (which can be read here), they also deviate substantively from them.
Some experts contend the discrepancies between the two documents are, at least in part, the result of industry influence. “The current system opens the guidelines up to lobbying and manipulation of data,” says Dr. Walter Willett, chair of the Department of Nutrition at Harvard School of Public Health, when asked why the Advisory Committee’s report is subject to changes from USDA and HHS. “The USDA’s primary stakeholders are major food producers and manufacturers,” he adds.
The question of meat
The absence of a top-line message about limiting red and processed meat has many experts, including spokespeople from the American Cancer Society, criticizing the guidelines. Studies have repeatedly linked heavy meat consumption to higher rates of heart disease, premature death and cancer. The Advisory Committee’s scientific report lumped red meat in with processed meats—stuff like salami and hot dogs—and said that a healthy diet would mean eating “lower” amounts of these foods in order to prevent chronic diseases.
By contrast, the final guidelines list red meat alongside seafood, poultry, and other protein sources as elements of a “healthy eating pattern.” In one chapter of the guidelines, it reads: “Lower intakes of meats, including processed meats … have often been identified as characteristics of healthy eating patterns.” They stop short of an explicit recommendation to eat less of it.)
Dr. Frank Hu, a professor of nutrition and epidemiology at Harvard and one of the experts who served on the Advisory Committee, says the meat industry has historically had “huge influence” on USDA.
In a statement emailed to TIME, a USDA spokesperson said, “HHS and USDA considered the Scientific Report of the 2015 Dietary Guidelines Advisory Committee, along with comments from the public and input from federal agencies.” These guidelines, the USDA says, are “updated to reflect the latest research and science, as well as our current understanding of the connections between diet and health.”
Some experts disagree, telling TIME that the discrepancies between the Advisory Committee’s report and the final guidelines are evidence that USDA and HHS do not rely on science to form their nutrition policies.
“There’s a great deal of money at stake in what these guidelines say,” says Dr. Marion Nestle, author of Food Politics and former chair of the Department of Nutrition, Food Studies, and Public Health at New York University. In the past, Nestle served as one of the experts HHS and USDA tapped to help craft the guidelines and this year was a peer reviewer for an earlier version of the 2015 report.
She says of years past: “I was told we could never say ‘eat less meat’ because USDA would not allow it.”
The debate over fat
This is not the first time experts have raised concerns about the guidelines.
“Throughout the 1980s and 1990s, the USDA treated fat as the primary harm in the American diet,” says Nestle. Along with its anti-fat stance—a stance researchers say was never grounded in science—the guidelines also encouraged Americans to eat hefty amounts of carbohydrates. The 1995 edition made bread, cereal, and pasta the foundation of its “Food Guide Pyramid,” and advised people to eat between six and 11 servings of grains every day, compared to just three to five servings of vegetables and two to four servings of fruit. Fat was to be eaten “sparingly.”
“This advice to eat more carbs and avoid fat is exactly backwards if you want to improve health and lower body weight,” says Dr. Robert Lustig, a pediatric endocrinologist at the University of California, San Francisco. He and other nutrition researchers say the popularity of anti-fat, pro-carb guidelines helped fuel a rise in diet-related health problems.
Since 1980, when the government issued its first set of dietary guidelines, the number of Americans who are obese or have type-2 diabetes has more than doubled. Roughly half of all American adults now live with one or more chronic, preventable diseases, and rates of childhood obesity have reached “epidemic” proportions, according to the National Institutes of Health.
In a sign of progress, the 2015 guidelines for the first time do not explicitly advise Americans to put a cap on the amount of fat in their diets. The new diet recommendations still advise limiting saturated fat to 10% of a person’s total calorie intake. Saturated fat’s place in a healthy diet remains controversial, with some experts saying the recommendations are out of step with the latest science. Others applaud the saturated-fat limit.
The guidelines’ ongoing promotion of low- and no-fat dairy is also the subject of some debate. Several recent review studies have suggested whole milk has a place in a healthy diet. Some studies have also linked full-fat dairy—but not reduced-fat dairy—to lower rates of weight gain and metabolic disease. The new guidelines, which also say average dairy intakes for most people are “far below” levels that fit into a “healthy U.S.-style pattern,” doesn’t dovetail with the opinions of most nutrition experts. “There’s just not scientific evidence to support such large amounts of dairy consumption,” Harvard’s Willett says, adding that industry influence may have played a role in that as well.
Signs of change
While some experts are critical of the guidelines, they also say the government’s health recommendations have historically influenced Americans’ diets in positive ways.
When the 2005 guidelines targeted dangerous trans fatty acids, for instance, the FDA soon required food manufacturers to list a product’s trans fat content on its nutrition label. This inclusion, Willett says, pushed many manufacturers—and soon after, fast food chains—to cut trans fats from their products. A recent report from Harvard School of Public Health lists lower trans fat consumption as one of the major reasons rates of premature death and disease fell among Americans adults from 1999 to 2012.
The new guidelines advise Americans to eat fewer refined grains and more whole grains—changes the latest research supports. The guidelines also advise Americans to reduce the amount of added sugar in their diets—a move that UCSF’s Lustig and others applaud. (Lustig’s research has shown the toxic effect of sugar, especially in children’s diets.)
If these added sugar recommendations take hold in ways similar to the 2005 trans-fat warnings, researchers say that could have a meaningful and lasting impact on the nation’s health.
It’s because the guidelines have this kind of influence that many stress the need for reform. Lustig and others say the guidelines should be simplified to emphasize “real” foods—especially plants—over processed or packaged goods.
The guidelines should also remove talk of recommended daily allowances (RDAs), Willett says. “This focus on RDAs is confusing and not helpful,” he explains, since people do not eat nutrients one by one but in combination, in the form of whole and processed foods. Many foods contain both beneficial and harmful components, he adds.
Many also contend the USDA should not play a primary role in shaping America’s dietary policies. Lustig says tasking the government agency that manages America’s food production with crafting nutrition policy is akin to “putting the fox in charge of the hen house.” Placing the guidelines solely in the hands of the Department of Health and Human Services would be a step in the right direction, Willett says.
Others argue the USDA’s long experience in crafting dietary policy serves the public well. “The real key is that the process is transparent and provides opportunities for public participation, and we think the current process does that,” says Jim O’Hara, director of health promotion policy for the independent Center for Science in the Public Interest.
O’Hara adds that removing political influence from the process is “wishful thinking.” He says: “Conflicts of interest and political pressures are present all across government, so the idea that you could insulate the guidelines from all that by making HHS solely responsible for them is unrealistic.”