Food balance sheets are commonly used to assess food consumption on the national level. They provide information on annual food production, distribution of food within the country, and imports and exports. They do not measure food actually consumed. The information from food balance sheets can be used to formulate agricultural policies, monitor changes over time, and compare food supplies among countries.
The gross national food supply is totaled by taking into account values of domestic food production, food taken from stocks minus exports, food added to stocks, food diverted for non-human food, and estimated waste. It is often converted to a daily per capita basis using population estimates for the country. This information can be found in the U.S. Department of Agriculture's Center for Nutrition Policy and Promotion publication The Nutrient Content of the U.S. Food Supply, 1909-94.
Commercial market databases report projected sales of packaged foods sold in grocery stores. This information can be used to analyze trends in consumer purchases of foods, food groups, or individual brands nation-wide.