Chapter 1 Background and Purpose of the Dietary Guidelines for Americans
The Dietary Guidelines for Americans [Dietary Guidelines], first published in 1980, provides science-based advice to promote health and to reduce risk for chronic diseases through diet and physical activity. The recommendations contained within the Dietary Guidelines are targeted to the general public over 2 years of age who are living in the United States. Because of its focus on health promotion and risk reduction, the Dietary Guidelines form the basis of federal food, nutrition education, and information programs.
By law (Public Law 101-445, Title III, 7 U.S.C. 5301 et seq.), the Dietary Guidelines is reviewed, updated if necessary, and published every 5 years. The process to create the Dietary Guidelines is a joint effort of the U.S. Department of Health and Human Services (HHS) and the U.S. Department of Agriculture (USDA) and has evolved to include three stages.
In the first stage, an external scientific Advisory Committee appointed by the two Departments conducted an analysis of new scientific information and prepared a report summarizing its findings.2 The Advisory Committee's report was made available to the public and Government agencies for comment. The Committee's analysis was the primary resource for development of the Dietary Guidelines by the Departments. A significant amount of the new scientific information used by the Dietary Guidelines Advisory Committee (DGAC) was based on the Dietary Reference Intake (DRI) reports published since 2000 by the Institute of Medicine (IOM), in particular the macronutrient report and the fluid and electrolyte report.
During the second stage, the Departments jointly developed Key Recommendations based on the Advisory Committee's report and public and agency comments. The Dietary Guidelines details these science-based policy recommendations. Finally, in the third stage, the two Departments developed messages communicating the Dietary Guidelines to the general public.
Because of the three-part process used to develop and communicate the 2005 Dietary Guidelines, this publication and the report of the DGAC differ in scope and purpose compared to reports for previous versions of the Guidelines. The 2005 DGAC report is a detailed scientific analysis that identifies key issues such as energy balance, the consequences of a sedentary lifestyle, and the need to emphasize certain food choices to address nutrition issues for the American public. The scientific report was used to develop the Dietary Guidelines jointly between the two Departments, and this publication forms the basis of recommendations that will be used by USDA and HHS for program and policy development. Thus it is a publication oriented toward policymakers, nutrition educators, nutritionists and healthcare providers rather than to the general public, as with previous versions of the Dietary Guidelines, and contains more technical information.
New sections in the Dietary Guidelines, consistent with its use for program development, are a glossary of terms and appendixes with detailed information about the USDA Food Guide and the Dietary Approaches to Stop Hypertension (DASH) Eating Plan as well as tables listing sources of some nutrients. Consumer messages have been developed to educate the public about the Key Recommendations in the Dietary Guidelines and will be used in materials targeted for consumers separate from this publication. In organizing the Dietary Guidelines for the Departments, chapters 2 to 10 were given titles that characterize the topic of each section, and the Dietary Guidelines itself is presented as an integrated set of Key Recommendations in each topic area.
These Key Recommendations are based on a preponderance of the scientific evidence of nutritional factors that are important for lowering risk of chronic disease and promoting health. To optimize the beneficial impact of these recommendations on health, the Guidelines should be implemented in their entirety.
IMPORTANCE OF THE DIETARY GUIDELINES FOR HEALTH PROMOTION AND DISEASE PREVENTION
Good nutrition is vital to good health and is absolutely essential for the healthy growth and development of children and adolescents. Major causes of morbidity and mortality in the United States are related to poor diet and a sedentary lifestyle. Specific diseases and conditions linked to poor diet include cardiovascular disease, hypertension, dyslipidemia, type 2 diabetes, overweight and obesity, osteoporosis, constipation, diverticular disease, iron deficiency anemia, oral disease, malnutrition, and some cancers. Lack of physical activity has been associated with cardiovascular disease, hypertension, overweight and obesity, osteoporosis, diabetes, and certain cancers. Furthermore, muscle strengthening and improving balance can reduce falls and increase functional status among older adults. Together with physical activity, a high-quality diet that does not provide excess calories should enhance the health of most individuals.
Poor diet and physical inactivity, resulting in an energy imbalance (more calories consumed than expended), are the most important factors contributing to the increase in overweight and obesity in this country. Moreover, overweight and obesity are major risk factors for certain chronic diseases such as diabetes. In 1999-2002, 65 percent of U.S. adults were overweight, an increase from 56 percent in 1988-1994. Data from 1999-2002 also showed that 30 percent of adults were obese, an increase from 23 percent in an earlier survey. Dramatic increases in the prevalence of overweight have occurred in children and adolescents of both sexes, with approximately 16 percent of children and adolescents aged 6 to 19 years considered to be overweight (1999-2002).3 In order to reverse this trend, many Americans need to consume fewer calories, be more active, and make wiser choices within and among food groups. The Dietary Guidelines provides a framework to promote healthier lifestyles (see ch. 3).
Given the importance of a balanced diet to health, the intent of the Dietary Guidelines is to summarize and synthesize knowledge regarding individual nutrients and food components into recommendations for an overall pattern of eating that can be adopted by the general public. These patterns are exemplified by the USDA Food Guide and the DASH Eating Plan (see ch. 2 and app. A). The Dietary Guidelines is applicable to the food preferences of different racial/ethnic groups, vegetarians, and other groups. This concept of balanced eating patterns should be utilized in planning diets for various population groups.
There is a growing body of evidence which demonstrates that following a diet that complies with the Dietary Guidelines may reduce the risk of chronic disease. Recently, it was reported that dietary patterns consistent with recommended dietary guidance were associated with a lower risk of mortality among individuals age 45 years and older in the United States.4 The authors of the study estimated that about 16 percent and 9 percent of mortality from any cause in men and women, respectively, could be eliminated by the adoption of desirable dietary behaviors. Currently, adherence to the Dietary Guidelines is low among the U.S. population. Data from USDA illustrate the degree of change in the overall dietary pattern of Americans needed to be consistent with a food pattern encouraged by the Dietary Guidelines (fig. 1).
A basic premise of the Dietary Guidelines is that nutrient needs should be met primarily through consuming foods. Foods provide an array of nutrients (as well as phytochemicals, antioxidants, etc.) and other compounds that may have beneficial effects on health. In some cases, fortified foods may be useful sources of one or more nutrients that otherwise might be consumed in less than recommended amounts. Supplements may be useful when they fill a specific identified nutrient gap that cannot or is not otherwise being met by the individual's intake of food. Nutrient supplements cannot replace a healthful diet. Individuals who are already consuming the recommended amount of a nutrient in food will not achieve any additional health benefit if they also take the nutrient as a supplement. In fact, in some cases, supplements and fortified foods may cause intakes to exceed the safe levels of nutrients. Another important premise of the Dietary Guidelines is that foods should be prepared and handled in such a way that reduces risk of foodborne illness.
USES OF THE DIETARY GUIDELINES
The Dietary Guidelines is intended primarily for use by policymakers, healthcare providers, nutritionists, and nutrition educators. While the Dietary Guidelines was developed for healthy Americans 2 years of age and older, where appropriate, the needs of specific population groups have been addressed. In addition, other individuals may find this report helpful in making healthful choices. As noted previously, the recommendations contained within the Dietary Guidelines will aid the public in reducing their risk for obesity and chronic disease. Specific uses of the Dietary Guidelines include:
Development of Educational Materials and Communications.
The information in the Dietary Guidelines is useful for the development of educational materials. For example, the federal dietary guidance-related publications are required by law to be based on the Dietary Guidelines. In addition, this publication will guide the development of messages to communicate the Dietary Guidelines to the public. Finally, the USDA Food Guide, the food label, and Nutrition Facts Panel provide information that is useful for implementing the key recommendations in the Dietary Guidelines and should be integrated into educational and communication messages.
Development of Nutrition-Related Programs.
The Dietary Guidelines aids policymakers in designing and implementing nutrition-related programs. The Federal Government bases its nutrition programs, such as the National Child Nutrition Programs or the Elderly Nutrition Program, on the Dietary Guidelines.
Development of Authoritative Statements.
The Dietary Guidelines has the potential to provide authoritative statements as provided for in the Food and Drug Administration Modernization Act (FDAMA). Because the recommendations are interrelated and mutually dependent, the statements in this publication should be used together in the context of an overall healthful diet. Likewise, because the Dietary Guidelines contains discussions about emerging science, only statements included in the Executive Summary and the highlighted boxes entitled "Key Recommendations," which reflect the preponderance of scientific evidence, can be used for identification of authoritative statements.
FIGURE 1. Percent Increase or Decrease From Current Consumption (Zero Line) to Recommended Intakes a,b
A graphical depiction of the degree of change in average daily food consumption by Americans that would be needed to be consistent with the food patterns encouraged by the Dietary Guidelines for Americans. The zero line represents average consumption levels from each food group or subgroup by females 31 to 50 years of age and males 31 to 50 years of age. Bars above the zero line represent recommended increases in food group consumption, while bars below the line represent recommended decreases.
a USDA Food Guide in comparison to National Health and Nutrition Examination Survey 2001-2002 consumption data.
b Increases in amounts of some food groups are offset by decreases in amounts of solid fats (i.e., saturated and trans fats) and added sugars so that total calorie intake is at the recommended level.
2For more information about the process, summary data, and the resources used by the Advisory Committee, see the 2005 Dietary Guidelines Advisory Committee Report (2005 DGAC Report) at http://www.health.gov/dietaryguidelines.
3 Hedley AA, Ogden CL, Johnson CL, Carroll MD, Curtin LR, Flegal KM. Prevalence of overweight and obesity among U.S. children, adolescents, and adults, 1999-2002. Journal of the American Medical Association (JAMA) 291(23):2847-2850, 2004.
4 Kant AK, Graubard BI, Schatzkin A. Dietary patterns predict mortality in a national cohort: The national health interview surveys, 1987 and 1992. Journal of Nutrition (J Nutr) 134:1793-1799, 2004.
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