Dietary Guidelines for Americans


The Dietary Guidelines for Americans provide nutritional advice for Americans older than 2 years. The Guidelines are published every 5 years by the US Department of Agriculture, together with the US Department of Health and Human Services.
The nominal purpose of the Dietary Guidelines for Americans is to help health professionals and policymakers to advise Americans about healthy choices for their diet. Although the Dietary Guidelines for Americans are purported to be based on a systematic review of the current body of nutrition science, critics have argued that the Advisory Committee tasked with formulating the plan for retrieval and analysis of the scientific evidence for the current edition of the DGA used a less than rigorous process for assessing the health effects of consumption of saturated fat and salt and for assessing the health effects of a low-fat, high-carbohydrate diet. This less than rigorous review of the nutrition science literature resulted in omission of multiple large, high-quality, clinical trials and also omission of some high-quality prospective observational studies. Some Advisory Committee members also had conflicts-of-interest that were not fully disclosed. For these reasons, the quality of the Advisory Committee's Scientific Report and the validity of the 2015–2020 DGA itself has been challenged by critics as being unduly influenced by commercial interests and as being flawed due to confirmation bias of some members of the Advisory Committee.

History

The efforts of the US Federal Government to establish a scientific basis for human nutrition began with Wilbur Olin Atwater, who published the first dietary recommendations for Americans in 1894, notably stating that, "We live not upon what we eat, but upon what we digest."
The Dietary Guidelines for Americans has been published every 5 years beginning in 1980, producing eight guidelines to date. One consistent recommendation of these eight guidelines has been that Americans reduce their dietary consumption of fat and animal products, including meat, dairy, and eggs and to increase their dietary consumption of carbohydrates and plant foods, including fruits, vegetables, and grains.

Purpose

The Guidelines were established so as to provide dietary advice that would improve the health of Americans and reduce their risk for chronic conditions, such as cancer, atherosclerosis, hypertension, heart disease, stroke, and renal disease. The Dietary Guidelines have the purpose of guiding the development of Federal policies and programs related to food, nutrition, and health. The guidelines influence and guide policymakers for Federally-financed food and dietary education programs. They also influence clinicians in the United States and in other countries.
The intended audience for the Dietary Guidelines for Americans are policymakers, nutrition scientists, and dieticians and other health professionals. The Guidelines themselves are not intended to directly inform the general public, but instead to serve as an authoritative, evidence-based information source that policymakers and health professionals can use to advise Americans about making healthy choices in their daily lives so as to enjoy a healthy diet that also prevents chronic disease. The Dietary Guidelines for Americans provide an evidence-base that is used by the Federal government to develop nutrition education materials for Americans.
Federal law and regulation require that Federal government publications provide dietary guidance consistent with the Dietary Guidelines for Americans. For the United States Department of Agriculture the guidelines provide the scientific rationale for the National School Lunch Program and School Breakfast Program, feeding 30 million children every school day, and the Special Supplemental Nutrition Program for Women, Infants and Children, which has 8 million beneficiaries. For the United States Department of Health and Human Services Administration on Aging, the guidelines provide the rationale for the Older Americans Act Nutrition Services programs which include more than 5,000 community-based nutrition service providers, serving more than 900,000 meals a day across the United States. The Department of Defense uses the guidelines as the rationale for meal rations for military personnel and the Department of Veterans Affairs uses the guidelines to inform nutrition education for veterans who are patients of the VA Hospital System. In addition to these governmental audiences, the Dietary Guidelines for Americans are widely used by state and local governments, schools, commercial enterprises, community groups, the media, and the food industry to inform policy and program development intended to serve the general public.

Current guidelines

The current Dietary Guidelines for Americans were developed in three stages, beginning with a review of scientific evidence, followed by development of the guidelines, and finally with implementation of the guidelines. Compared to previous guidelines, the 2015–2020 guidelines emphasized replacing saturated fats with unsaturated fats, particularly polyunsaturated fats, with the goal of preventing heart attack and stroke.
The guidelines provide a general recommendation that people follow a healthy eating pattern with appropriate calories, and that the evaluation of one's eating pattern accounts for all foods and beverages, including snacks. The recommended healthy eating pattern includes:
Include these in diet:
Limit these in diet:
The Dietary Guidelines also include a key recommendation to meet the Physical Activity Guidelines for Americans.
The MyPlate initiative, based on the recommendations of the 2015—2020 Dietary Guidelines for Americans and produced by the USDA Center for Nutrition Policy and Promotion, is a nutrition education program directed at the general public, providing a guide to "finding healthy eating solutions to fit your lifestyle."

Future guidelines

The USDA has invited interested parties, including members of the general public, to participate and follow the development of the 2020–2025 edition of the Dietary Guidelines for Americans. As mandated by the Agriculture Act of 2014, this next edition of the guidelines will cover the full life-span of Americans, as expansion of the guidelines are planned to include recommendations for pregnant women, infants, and children younger than 2 years old. The Trump Administration has proposed a budget of more than $12 million for the evaluation of scientific evidence, development of the 2020–2025 Dietary Guidelines for Americans, and dissemination of the new edition to its target audience of policymakers, nutrition experts, and clinicians; this budget request has been supported by multiple organizations.

Criticisms of the 2015–2020 Guidelines

Each edition of the Dietary Guidelines for Americans has had attendant controversy, with objections particularly from scientists whose point-of-view was not reflected in the guidelines and from commercial interests negatively affected by the recommendations therein. The response to the 2015–2020 guidelines was particularly contentious, resulting in action by Congress mandating the National Academies of Sciences, Engineering, and Medicine to evaluate the process used to update the DGA. This review by the National Academies resulted in two reports. The first report, entitled "Optimizing the Process for Establishing the Dietary Guidelines for Americans: The Selection Process", identified opportunities for improving the process for selecting members of the Dietary Guidelines Advisory Committee. In September, 2018 the USDA issued an official response to the first report of the National Academies committee. The second report from National Academies of Sciences, entitled "Redesigning the Process for Establishing the Dietary Guidelines for Americans", offers an exhaustive review and provides recommendations for improving the process of revising the Dietary Guidelines so as to best identify, analyze, and present the scientific evidence.

Methodology

One critic contends that the current guidelines do not promote the public interest and have been corrupted by regulatory capture, advancing the commercial concerns of agribusiness and large food processors, and the political concerns of scientists intent on preserving their point-of-view. Another critic notes that the DGAs make recommendations that overvalue the findings of observational studies and surrogate measures of outcomes and that undervalue the findings of high-quality randomized controlled trials.
There is compelling evidence that food frequency questionnaires and other methods that rely on human memory do not accurately measure dietary intake. An analysis of the validity of the methods used by the USDA to estimate per capita calorie consumption found that these methods lack validity and the authors of this study recommend that these methods not be used to inform public policy. A systematic review found that only a few studies have measured the accuracy or reliability of dietary assessment methods in schoolchildren. The few studies that have been done found that schoolchildren did not accurately report foods consumed but that they did accurately report total calories consumed. The 2015 Guidelines were based on the Scientific Report of the 2015 Dietary Guidelines Advisory Committee, which did not rely on actual measurements of dietary intake but instead relied on memory-based dietary assessments, including interviews and surveys despite clear evidence that such methods markedly underestimate actual calorie consumption and nutrient intake. Thus, the conclusions expressed in the Scientific Report have been criticized, and the Dietary Guidelines for Americans are considered invalid by some experts, as the DGAs rely on invalid methods and draw conclusions that do not agree with the available scientific literature.

Restriction of dietary fat and cholesterol

The Dietary Guidelines for Americans have been criticized for recommending a diet that is low in total fat, and for not adequately emphasizing the harmful effect of industrially-produced trans fats. A systematic review of 62,421 participants in 10 dietary trials found that reducing dietary fat intake had no effect on coronary heart disease and had no effect on overall mortality. The authors of this meta-analysis conclude that the available evidence from randomized controlled trials does not support the recommendation of the 2015–2020 Dietary Guidelines for Americans that people reduce their fat intake. A 2020 meta-analysis found that replacing dietary saturated fats with polyunsaturated fats for two years reduced risk of cardiovascular events. However, this meta-analysis has been criticized based on the statistical methods used by Hooper et al and the subsequent re-analysis of the same clinical trials found that reducing dietary saturated fat did not reduce risk of cardiovascular disease.
The Dietary Guidelines for Americans recommends limiting dietary cholesterol intake to as little as possible while maintaining healthy eating patterns, which implies reduction or avoidance of consumption of high-cholesterol foods, such as eggs. A review of reviews also confirmed that egg consumption is associated with adverse effects regarding Heart failure and type 2 diabetes.

Dietary salt restriction

The Dietary Guidelines for Americans have been criticized for recommending a diet that contains less than 2.3 grams of sodium. Notably, 95% of the world's populations have a mean intake of salt that is between 6g and 12g daily and evidence on the health effects of salt does not support such a severe restriction on salt intake. An analysis of dietary guidelines found that this recommendation for restriction of salt intake is not supported by evidence from randomized controlled trials nor is it supported by evidence from prospective observational studies. In fact, intake of less than 5.8 g of salt per day typically results in activation of the renin-angiotensin-aldosterone system, which leads to an increase in plasma lipids and increased mortality. The authors of this analysis suggest a redesign of the dietary guidelines for salt intake is needed.
A Committee of the National Academies Institute of Medicine evaluated the evidence about dietary salt intake and health. Overall, the committee found evidence that higher salt intake was associate with increased risk of cardiovascular disease. However, the Committee also found that the evidence did not support the claim that lowering sodium intake in the general population to less than 2,300 mg/day was associated with a lower risk of death nor with a higher risk of death.

Alcoholic beverage consumption

The Dietary Guidelines for Americans recommend limiting alcoholic beverages consumption to no more than 1 drink daily for women and no more than 2 drinks daily for men. The 2015–2020 Scientific Report of the Dietary Guidelines Advisory Committee asserts that most studies show that moderate consumption of alcohol has been shown to be part of a beneficial dietary pattern. However, a systematic review and meta-analysis of scientific studies of alcohol consumption and all-cause mortality found that consumption of up to 2 alcoholic beverages per day had no net mortality benefit compared with lifetime abstention from alcohol. A systematic analysis of data from the Global Burden of Disease study found that consumption of ethanol increases the risk of cancer and increases the risk of all-cause mortality, and that the level of ethanol consumption that minimizes disease is zero consumption.
The Guidelines recommend that people not mix alcohol and beverages containing caffeine, as this combined intake may result in greater alcohol consumption, with a greater risk of alcohol-related injury.

Classification of honey and maple syrup as "added sugars"

Producers of honey and maple syrup have objected to the proposed Federal regulatory requirement that honey and maple syrup include the term "added sugar" on product labeling, despite the fact that no additional sugar is added to these products. This regulatory requirement follows from the recommendation in the 2015–2020 Guidelines that added sugars be limited to less than 10% of calories and that honey and maple syrup are themselves considered by federal regulators to be added sugars.