Calorie supply by food group, 2017 Daily supply of calories is measured in kilocalories.

The USDA, Economic Research Service (ERS) Food Consumption and Nutrient Intakes data product analyzes and reports information from federally conducted surveys of nationally representative samples of U.S. consumers to provide researchers, policymakers, and program staff with useful insights on that important question.

The ERS tables draw on data collected as part of the What We Eat in America, National Health and Nutrition Examination Surveys (NHANES) conducted in 2015–16 and 2017–18. As part of the NHANES, trained interviewers collect information from a national sample of individuals on the foods they ate over a 24-hour period and where those foods were obtained (from the home food supply, a restaurant, etc.). Although NHANES collected two of these 24-hour interviews over 2 nonconsecutive days, the ERS tables use data from only the first interview day to arrive at average food group and nutrient intakes. NHANES also collects demographic information on participants that enables subgroup analysis by different factors, such as household income.

The Dietary Guidelines for Americans recommends the consumption of food groups such as vegetables, fruits, grains, dairy, and protein foods, which includes meat, poultry, eggs, seafood, nuts, seeds, and soy. However, individuals frequently eat foods that are a combination of items from multiple food groups. For example, a slice of apple pie includes apples, a fruit, but also sugar added to the filling and a crust that was made with flour (grain) and fat. To estimate food group consumption, USDA’s Agricultural Research Service (ARS) combines NHANES data with its Food Patterns Equivalents Database (FPED) to separate foods as consumed into their respective food group component amounts. Continuing with the example, a slice of apple pie would be separated into the appropriate amounts of fruit, added sugars, grain, and solid fat or oils. FPED has been regularly updated by ARS for use with NHANES surveys through 2018; ARS also generates estimates of nutrients obtained from foods consumed.

ERS researchers use these data to calculate the average daily consumption of food groups and selected nutrients identified as priorities by Federal dietary guidance, with results in tables provided on the ERS website. These data tables also report the average consumption per 1,000 calories, which is referred to as the food or nutrient density of the diet. This measure is used to obtain information on the quality of the diet when controlling for differences in amounts consumed. Estimates are calculated for the overall daily intake and by source. Sources are categorized as foods prepared at home (FAH), which are typically purchased from a grocery store or supermarket, and foods prepared away from home (FAFH), such as foods from restaurants and fast-food establishments. All estimates are presented for the total U.S. population above the age of 2 and by household income level. The graphic below provides details on the type of information that can be found in these data tables.

Examining the data by income group, we find that FAFH is a part of U.S. diets at all household income levels, but there is some difference in the importance of specific FAFH sources (see figure 2 below). While fast food contributes virtually the same amount of calories to households in all income groups, the average calories obtained from restaurant foods by households in the highest-income group is almost twice that of the average for the lowest income group. This is probably not surprising since restaurant foods would be the most expensive FAFH. In contrast, the average contribution of school food is highest for the lowest income household groups; children in this group would generally be eligible to obtain USDA school meals for free or at a reduced price.