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2020 Dietary Guidelines Advisory Committee: Approaches to Examine the Evidence

The 2020 Dietary Guidelines Advisory Committee used three approaches to examine the evidence: data analysis, food pattern modeling, and NESR systematic reviews. Each of these approaches has its own rigorous, protocol-driven methodology, and played a unique, complementary role in examining the science. For each approach, staff from USDA and HHS supported the Committee’s review of the evidence. The type of information the Advisory Committee needed to answer each scientific question determined which approach they would use to review the evidence.

To answer each scientific question, the Advisory Committee developed a protocol – or a plan that described how the Committee would apply the methodology of one of the three approaches to examine the evidence related to that specific question. A protocol was created before the Committee examined any evidence, and, for the first time, was posted online for the public to view to understand how a specific scientific question would be answered and to have the opportunity to submit public comments prior to the protocol being finalized. 

For all topics and questions, regardless of the path used to identify and evaluate the scientific evidence, the Committee developed conclusion statements to answer each question. Each draft conclusion statement described the state of the science, based on the evidence considered, in order to answer the specific question examined. The Scientific Report of the 2020 Dietary Guidelines Advisory Committee includes the Committee’s conclusion statements for each question and provides its advice and recommendations to USDA and HHS based on the entirety of its work. 

More information about the methodologies for each of the three scientific approaches is available in the Scientific Report of the 2020 Dietary Guidelines Advisory Committee. This section provides a brief overview of the three approaches. 

three methods
data analysis bar graph


Data Analysis

A collection of analyses that uses national data sets to describe the current health and dietary intakes of Americans. These data help make the Dietary Guidelines practical, relevant, and achievable.

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Food Pattern Modeling

Analyses that illustrates how changes to the amounts or types of foods and beverages in a dietary pattern might affect meeting nutrient needs across the U.S. population.

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food pattern modeling computer with graphs on screen
systematic reviews current two papers stcaked


NESR Systematic Reviews

Research projects that answer questions on diet and health by searching for, evaluating, and synthesizing all relevant, peer-reviewed studies within a specified date range.

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