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  1. Total Diet Study

Total Diet Study Design

Please note: The FDA will be updating this page with new information about our efforts to modernize the Total Diet Study, in the near future. The modernization efforts include data management, methods, data quality standards, and study design improvements. In October 2017, a pilot program was initiated to test a more robust, population-based sample collection procedure. These improvements will help the FDA to continue our decades long effort to study and better understand Americans’ dietary exposure to toxic and nutritional elements, pesticides, industrial chemicals, and radionuclides.

CFSAN/Office of Analytics and Outreach

To conduct the Food and Drug Administration’s Total Diet Study (TDS), we buy samples of food at retail outlets throughout the U.S., prepare the foods as they would be consumed, and analyze them, to measure levels of selected pesticide residues, industrial chemicals, radionuclides, and toxic and nutrient elements. We use the data to calculate estimates of annual dietary intakes of those contaminants and nutrients by the U.S. population.

About every 10 years, we update the list of foods to be tested and our estimates of the amounts that consumers eat of those foods, to reflect changing eating patterns in the U.S. Likewise, we periodically update the methods we use to analyze the foods.

Market Baskets

Total Diety Study Collection Market Basket Regions

We generally collect TDS “market baskets” (abbreviated “MB”) – the specific foods to be analyzed – four times each year, once in each of four regions of the country (North Central, West, South, and Northeast). To the extent possible, the market baskets are identical from region to region. Each region consists of three cities that differ every year, in which the foods are collected from supermarkets, grocery stores, and fast-food restaurants.

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The TDS Food List

The foods collected for the TDS market baskets represent the major components of the average diet of the U.S. population, from infants to adults, based on results of national food-consumption surveys. For the first TDS update shown on this website, in which we had analyzed market baskets collected between 1991 - 2002, we had based the list of foods to be collected on the USDA 1987-88 Nationwide Food Consumption Survey (USDA, 1990).

In the 2003 food-list update, which we began applying to market-basket collections in 2003, we based the food list on the USDA's 1994-96, 1998 Continuing Survey of Food Intakes by Individuals (CSFII) (USDA, 2000). (See the food / analyte matrix available on the Food and Analytes page of this website.) The survey included detailed information on the types and amounts of food consumed by the survey participants, who collectively reported on more than 5,000 different foods (USDA, 2000).

We made this large number of foods more manageable by aggregating the foods into groups according to similarity (for example, a given group might include the various kinds of fish included in the survey). For each group, we then assigned the most-consumed food within that group as the representative of all the foods in the group, and designated it as the TDS food; in other words, each of the 280 foods on the TDS Food List may actually represent several foods.

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Laboratory Analyses

After we collect the foods, we ship them to a central FDA laboratory for preparation and analysis. For each kind of food, we combine samples from each of the three separate cities of the region to form one composite sample of that particular food.

Within a given market-basket region, samples of TDS foods are collected from three different cities.  For each food, the samples from the three cities are combined into a composite sample.

For each TDS food, the samples from each of the three cities
in a region are formed into a composite.

Numerous FDA units participate in the operation of the TDS. The Center for Food Safety and Applied Nutrition (College Park, MD) provides overall management of the program and summarizes the laboratory results. FDA District Offices from across the U.S., under the Office of Regional Affairs, collect the foods and ship them to the FDA Kansas City District Laboratory (Lenexa, KS), which prepares and analyzes them for toxic elements, nutrient elements, and pesticides. Portions of the prepared composites from two market baskets per year are sent to FDA's Winchester Engineering and Analytical Center (Winchester, MA) for radionuclide analyses. After we have reviewed and finalized the results of the analyses, we post them on this website.

The samples that have been collected go to FDA's Kansas City District lab, where all of the samples are prepared for analysis.  Portions of the samples of the various foods are then analyzed on-site for toxic elements, nutrients, pesticides, and industrial chemicals.  Portions also go to FDA's Winchester Engineering and Analytical Center, where they are analyzed for radionuclides.

Where samples are prepared and analyzed.

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Consumption Amounts

Each of the approximately 10-year iterations of the TDS is based not only on an updated food list, but also on updated consumption amounts. To estimate dietary exposure to each TDS analyte, we: 

  • determine the average level of that analyte in each TDS food.
  • estimate the average amount the U.S. population (or age / gender subpopulation) consumes of each TDS food.
  • for each TDS food, multiply the average level of that analyte in that food by the average amount the U.S. population (or age / gender subpopulation) consumes of that food.
  • combine the results to arrive at the estimated total dietary exposure to the analyte among the U.S. population (or age / gender subpopulation).
Age and gender groups for whom we have calculated TDS consumption amounts




Males & Females, Combined

6 - 11 months



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2 yrs



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6 yrs



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10 yrs



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14 - 16 yrs

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25 - 30 yrs

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40 - 45 yrs

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60 - 65 yrs

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70+ yrs

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To calculate average per-capita daily consumption amounts for a given food on the TDS Food List, we first go back to the group of foods from the surveys; that is, the multiple foods that the TDS food represents. We calculate per-capita consumption amounts for each of the foods within that group and combine them into a single figure. We use that single figure as the per-capita consumption amount for that TDS food. (See graphic below.)

Parts 1 and 2 of this figure explain that we group together similar foods from consumption surveys and represent each group with one food, which is called the TDS food. Part 3 of the figure explains that we use the same concept to calculate average per-capita consumption of each TDS food; that is, we combine the per-capita consumption amounts of all of the individual foods in the group that the TDS food represents. This figure is a broad, general description of the concept; it does not address specific groups or specific foods.

You can use a mapping file we created to map any of the more-than 7,900 food codes in the 2003-2014 National Health and Nutrition Examination Survey (NHANES), What We Eat In America (WWEIA) to the 267 TDS Foods (i.e., the TDS Foods List) we analyzed in 2014, to find their representative chemical concentrations. To request the file, contact TDS@fda.hhs.gov. As noted earlier, each of the 267 TDS Foods represents a large group of similar foods. The concentrations of chemicals in each of the 267 TDS Foods applies to all of the foods in the group the TDS Food represents (a limitation that should be noted when reporting chemical concentrations estimated via the TDS and the TDS mapping file). Data on the TDS Foods’ chemical concentrations can be downloaded from the TDS Website. Please see the Analytical Results page.

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Resources For You

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