Information obtained from health.gov -
Over the past century, deficiencies of essential nutrients have dramatically decreased, many infectious diseases have been conquered, and the majority of the U.S. population can now anticipate a long and productive life. At the same time, rates of chronic diseases—many of which are related to poor quality diet and physical inactivity—have increased. About half of all American adults have one or more preventable, diet-related chronic diseases, including cardiovascular disease, type 2 diabetes, and overweight and obesity.
However, a large body of evidence now shows that healthy eating patterns and regular physical activity can help people achieve and maintain good health and reduce the risk of chronic disease throughout all stages of the lifespan. The 2015-2020 Dietary Guidelines for Americans reflects this evidence through its recommendations.
The Dietary Guidelines is required under the 1990 National Nutrition Monitoring and Related Research Act, which states that every 5 years, the U.S. Departments of Health and Human Services (HHS) and of Agriculture (USDA) must jointly publish a report containing nutritional and dietary information and guidelines for the general public. The statute (Public Law 101-445, 7 U.S.C. 5341 et seq.) requires that the Dietary Guidelines be based on the preponderance of current scientific and medical knowledge. The 2015-2020 edition of the Dietary Guidelines builds from the 2010 edition with revisions based on the Scientific Report of the 2015 Dietary Guidelines Advisory Committee and consideration of Federal agency and public comments.
Learn more about these guidelines here: http://health.gov/dietaryguidelines/2015/guidelines/executive-summary/