WASHINGTON – The latest data on U.S. food availability per capita in a U.S.D.A. database that researchers, policymakers, media and marketers use to gauge consumption of individual foods and food groups was unveiled Feb. 18 by Agriculture Secretary Thomas Vilsack. For many of the food commodities covered, this most recent release marks 100 years of data - from 1909 to 2008.

"At a time when the alarm has been clearly sounded on the epidemic of obesity in America, particularly among our children, the ability to track dietary trends is a crucial element of efforts to combat obesity and prevent its adverse health outcomes," Mr. Vilsack said. "The only source of long-term food consumption in the country is our Food Availability Data System."

This most recent data in the online Food Availability Data System were released on the first day of USDA's annual two-day Agricultural Outlook Forum. The release of the one-hundredth year of data is accompanied by enhanced features in the data product to improve usability, as well as an added multimedia presentation that highlights the uses and implications of the data.

U.S.D.A.'s Economic Research Service (E.R.S.), which created and maintains the data system, updates it annually. "Food availability" is essentially the per capita amount of food in the U.S. food marketing system available for consumption. E.R.S. economists include production and imports of the various foods, and exclude exports as well as farm and industrial uses, to arrive at an approximation of what Americans consume on average.

Food availability includes all food – from grocery stores, restaurants, school cafeterias and other eating places.

"Food availability is a popular proxy for per-capita food consumption," said Jean Buzby, one of the economists who maintain the database. "Looking at 100 years of American eating, we can see a reflection of social, economic, and technological developments – including health concerns."

Per capita availability of chicken, for example, increased five-fold in the past century, illustrating advances in product development, mass production and more recently, health concerns associated with fat and cholesterol content of meats.

Since the food availability data do not take into account the quantities lost through waste, moisture loss, spoilage and inedible portions, the data overstate the amount actually ingested. Therefore, in the 1990s E.R.S. developed a second data series in the system that adjusts for spoilage and other losses at the farm, retail/restaurant, and consumer levels for raw and semi-processed agricultural commodities, dating from 1970.

This series converts the loss-adjusted amounts into daily per capita calories and food serving equivalents. Data users can compare these food serving equivalents to federal dietary recommendations for grains, meat, fruits and vegetables, and other foods. The third series in the data system presents estimates compiled by USDA's Center for Nutrition Policy and Promotion on calories and 27 nutrients in the various food groups.

The U.S.D.A. Food Availability (Per Capita) Data System is accessible to the public, at www.ers.usda.gov/Data/FoodConsumption/.