The National Nutrition Monitoring and Related Research Act
The 1980, 1985, and 1990 editions of the Dietary Guidelines were issued voluntarily by the two Departments. With the passage of the 1990 National Nutrition Monitoring and Related Research Act, the 1995 edition of Nutrition and Your Health: Dietary Guidelines for Americans became the first Dietary Guidelines Congressionally mandated by statute. This Act directs the Secretaries of USDA and HHS to jointly issue at least every five years a report entitled ‘Dietary Guidelines for Americans.’
Evolving Focus: From Nutrients to Dietary Patterns
Since 1980, the Dietary Guidelines have been notably consistent on what components make up a healthful diet, but they also have evolved in some significant ways to reflect updates to the science.
Previous editions of the Dietary Guidelines relied on the body of science looking at the relationships between individual nutrients, foods, and food groups and health outcomes. Although this science base continues to be substantial, science has progressed. There is now a body of science looking at the relationship between overall eating patterns and various health outcomes.
Just as nutrients are not consumed in isolation, foods and beverages are not consumed separately either. Rather, these are consumed in various combinations over time—an eating or dietary pattern. The current science base shows that components of an eating pattern can have interactive, synergistic, and potentially cumulative relationships, such that the eating pattern may be more predictive of overall health status and disease risk than individual foods or nutrients. Thus, eating patterns, and their food and nutrient components, are at the core of the 2015-2020 Dietary Guidelines.
Advancement in Methods to Review the Science
Providing the public with science-based dietary guidance is core to the Dietary Guidelines. The nutrition science that informs revisions to each edition of the Dietary Guidelines is documented in the Advisory Committee’s scientific report. With the growing emphasis on data quality in developing clinical and public health recommendations, the 2005 Advisory Committee made advancements by using a more systematic approach for reviewing the body of science than previous advisory committees. This systematic review of the evidence was further realized for the 2010 Advisory Committee with USDA’s creation of the Nutrition Evidence Systematic Review (NESR) (formerly known as the Nutrition Evidence Library).
The NESR uses a state-of-the-art approach to search, evaluate, and synthesize the body of food and nutrition-related science. This rigorous, protocol-driven approach is designed to minimize bias, increase transparency, and ensure relevant, timely, and high-quality systematic reviews to inform Federal nutrition-related policies, programs, and recommendations. The NESR was also used to support the completion of original systematic reviews for the 2015 Advisory Committee. Existing systematic reviews from other entities that are relevant, timely, and of high-quality have also been a source of evidence of previous Advisory Committees.
Another approach used is food pattern modeling. The 2005 Advisory Committee was the first to introduce this approach to help the committee describe the types and amounts of foods to eat that can provide a nutritionally adequate diet. This approach was also used and expanded by the 2010 and 2015 Advisory Committees and included modeling of multiple types of diets informed by the science.
The scientific foundation of the 2015-2020 Dietary Guidelines was based on the findings from the Advisory Committee’s scientific report, which was informed by the following methods:
- Original systematic reviews of scientific research;
- Review of existing systematic reviews, meta-analyses, and reports by Federal agencies or leading scientific organizations;
- Food pattern modeling analyses; and
- Analyses of current intake of the U.S. population.
Together, these complementary approaches provide a robust evidence base for the development of dietary guidance. With each edition of the Dietary Guidelines, USDA and HHS are committed to reviewing these and other methods to ensure that the best dietary advice is available to promote health and help prevent disease for all Americans.
Addressing Public Health Needs
From the Dietary Goals to the current Dietary Guidelines, the goals and recommendations have been a way to address public health concerns related to the role of the diet in health promotion and disease prevention. Earlier editions of the Dietary Guidelines focused specifically on healthy Americans ages 2 years and older, more recent editions also have included those who are at increased risk of chronic disease. While the Dietary Guidelines are not directly intended for disease treatment, they can be – and often are – adapted by medical and nutrition professionals to encourage their patients to follow healthy eating patterns. Research has shown that each step closer to eating a diet that aligns with the Dietary Guidelines reduces risk of heart disease, type 2 diabetes and cancer.
Nutrition and health professionals actively promote the Dietary Guidelines as a means of encouraging Americans to focus on eating a healthful diet and being physically active at each life stage. Future editions of the Dietary Guidelines will continue to evolve to reflect the body of science that is available. Additionally, the Dietary Guidelines will expand to include focused guidance for women who are pregnant and breastfeeding, as well as infants and toddlers from birth to 2 years of age.
Related Reading and Resources
Previous Editions of the Dietary Guidelines
Table of Dietary Guidelines Development
Dietary Guidelines Infographic
Historical Dietary Guidance Digital Collection