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NHANES Dietary Web Tutorial

Resources for Dietary Data Analysis


Researchers often employ sources of information other than the data themselves when conducting dietary analysis studies.  These include databases, search tools, and food grouping schemes.  Most of these research resources are used with the dietary recall data but some also can be used with either the dietary supplement or food frequency data.


Task 1: Describe the Food and Nutrient Database for Dietary Studies (FNDDS)

The Food and Nutrient Database for Dietary Studies, or FNDDS, is a database of foods, their nutrient values, and their gram weights for typical food portions.  It is used to process the NHANES dietary recall data that are included in the two types of dietary data files (individual foods file and total nutrients file) and also can be used as a resource in analyzing NHANES dietary data.


Task 2: Describe the USDA Food Coding Scheme

The USDA food coding scheme provides a numeric identifier based on hierarchical grouping for each of the thousands of foods in the FNDDS.  The coding scheme may be used to categorize individual foods into groups that are appropriate for your research needs.  This is important because similar foods are often grouped, rather than analyzed individually, in research studies.  You can use this coding scheme to develop your own food groups.  Alternatively, you can use the food groups defined by USDA (see Task 3).


Task 3: Describe Food Surveys Research Group (FSRG)-Defined Food Groups

USDA's Food Surveys Research Group (FSRG) has developed a grouping scheme to aid in reporting food intake estimates.  It groups the foods in the FNDDS into 71 food groups and subgroups, and the documentation contains a short description of the foods included and excluded in each.

Task 4: Describe the What's In the Foods You Eat Search Tool

The USDA's What's in the Foods You Eat tool is a database that allows you to search for foods included in the FNDDS.  This search tool is useful for accessing information about individual as well as grouped foods.

Task 5: Describe the MyPyramid Equivalents Database

The MyPyramid Equivalents Database (MPED) provides MyPyramid food group amounts, expressed as numbers of cup equivalents, ounce equivalents, teaspoon equivalents, or grams, in the foods reported eaten in a recall day.  All foods in the FNDDS identified by food codes (e.g., lasagna) are disaggregated into their component ingredients (e.g., pasta, mozzarella, beef), and these ingredients have been converted to equivalent amounts of relevant MyPyramid food groups (e.g., grains, milk, meat).


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