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The Dietary Guidelines
for Americans are designed to help Americans choose diets that
will promote good health and reduce risk for chronic diseases, such
as heart disease, certain types of cancer, diabetes, stroke, and
osteoporosis. Different foods contain different nutrients and other
healthful substances. No single food can supply all the nutrients
in the amounts a person needs. To get all the nutrients and other
substances we need, the Dietary Guidelines recommend "let the
Pyramid guide
your food choices." As a starting point, consumers should choose
the number of daily servings from each of the five major food groups
according to the recommendations from the Food Guide Pyramid. Data from the Continuing Survey of Food Intakes by Individuals
(CSFII) 1994-96 can be used to assess how closely consumers are
following the Food Guide Pyramid. Two sets of tables from ERS report food and nutrient intake and
compare American's diets to recommendations of the Food Guide Pyramid
and the 2000 Dietary Guidelines for Americans.
Food consumption tables provide estimates of food consumption in relation to recommendations from the Food Guide Pyramid.
Nutrient intake tables provide estimates of nutrient intake in relation to recommendations from the 2000 Dietary Guidelines for Americans.
For each set of tables, we first report average consumption/intake and the proportion of consumers meeting the recommendation. Then we look at consumption/intake by location, from which we can link dietary deficiencies to locations where foods are prepared. In both sets of tables, we report data for Americans ages 2 and older, children ages 2-18, and seniors ages 60 and older.
Individual Survey Data
Since the 1930's, USDA has conducted seven food consumption surveys
on a National scale: 1936, 1942, 1948 (urban only), 1955, 1965-66,
1977-78, and 1987-88. The data have been used to describe food consumption
patterns and to assess the nutritional contents of diets. Research
based on the surveys has influenced policies related to food production
and marketing, food safety, food assistance, and nutrition education.
The 1977-78 and 1987-88 surveys included two components: (1) household
food use during a 7-day period and (2) individual food intakes for
3 days. While the household food use component has not been conducted
since 1987-88, the individual food intake component, the CSFII,
was conducted during 1989-91, 1994-96, and 1998.
The CSFII measures foods actually eaten by individuals. The survey
records food intake over specific periods of time (2 nonconsecutive
days during 1994-96 using 24-hour dietary recalls). In addition
to food-intake data, the survey collects demographic information,
such as household size, income, race, age, and sex, and information
on where a food was purchased, how it was prepared, and where it
was eaten. The CSFII provides information for use in policy formation,
regulation, program planning and evaluation, education, and research.
For example, data from recent surveys have been used to evaluate
the effect of food fortification on nutrient intakes, estimate exposure
to pesticide residues and other contaminants from foods, and target
nutrition assistance and education programs to those who need them
most. The data are particularly valuable for measuring the effect
of socioeconomic and demographic characteristics on food consumption.
Get
more information about the CSFII.
Nutrient Intakes of Low-Income Households
To evaluate the effects of food assistance programs, such as the
Food Stamp Program, one needs to determine what the percentage change
in the quantity of food demanded by a consumer would be with a change
in the price of the food, the price of competing or complementary
foods, or the consumer's income. This is known as the "elasticity
of demand," and researcher's need separate demand elasticity
estimates for households of different income levels. Most available
demand elasticities are estimated from time-series data based on
average consumer behavior and may not well represent the low-income
households of concern. ERS used data from the 1987-88 Nationwide
Food Consumption Survey to estimate demand elasticities for households
segmented by income levels. For more information on this study,
go to the report, Estimation
of Food Demand and Nutrient Elasticities from Household Survey Data.
In this study, ERS developed an approach for estimating a demand
system from household survey data. The study used the unit values
of foods available in household surveys as variables to model a
food demand system. Because the unit values of foods reflect market
prices and consumer choices of food quality, we adjusted the estimates
by excluding the food quality effects and obtained a complete set
of demand information, including own-price, cross-price, and expenditure
elasticities. This approach is particularly useful in estimating
a demand system when obtaining time series data is difficult or
when the estimates of demand elasticities across different population
groups are required for food policy decisionmakers.
ERS classified all households into three income groups and then
estimated the demand structures for both the entire sample of households
and each group of households. Most estimated demand elasticities
were statistically significant and consistent with economic theory
in sign and magnitude. This study's estimates of food quality effects
show that food quality plays a significant role in household budget
allocation and that food quality is an important factor in modeling
a food demand system from household survey data. Results show that
the estimated demand elasticities were different across income groups.
For example, the price elasticity of beef for the low-income group
was -0.29 compared with -0.41 for the high-income group. The price
elasticity of demand for fruits was -0.65 for the low-income group
and -0.75 for the high-income group. This finding suggests that
food policy analysis should use the demand elasticity of a specific
income group (for example, the low-income group) when that group
is the household of interest.
We also used the estimated demand elasticities for low-income households
to measure nutrient income elasticities—the percentage change
in nutrient availability with respect to changes in household food
expenditure. The results indicate that consumption of all 13 food
groups increases as food expenditures increase. Consequently, the
nutrient elasticities with respect to food expenditure and with
respect to food stamp benefits were positive for the 25 nutrients
studied.
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