WASHINGTON — More than 49.1 million Americans, 16.7 million of them children, lived in food-insecure households in 2008, according to a report issued by the Economic Research Service of the U.S. Department of Agriculture on Nov. 16. The number of individuals living in food-insecure households represented 16.4% of all Americans. In comparison, 36.2 million Americans, or 12.2% of all Americans, lived in food-insecure households in 2007.

The data were contained in the “Household Food Security in the United States” report for 2008. The report and its findings were based on a survey of about 44,000 American households comprising a representative sample of the U.S. civilian population of 118 million households. The E.R.S. has conducted the survey each year since 1995. In no other year in the report’s history has both the number of individuals and the number of households lacking food security in this country been higher.

During 2008, no sooner had food prices begun to decline after reaching historical highs than the worst economic recession since the 1930s erupted in the United States and around the world. These circumstances without doubt were principally responsible for the increased number of food-insecure households in the United States even as they were responsible for pushing the number of hungry persons worldwide above 1 billion. Recent U.S. efforts to shore up its food security safety net as expressed in American Recovery and Reinvestment Act of 2009 will not be reflected in survey data until next year.

The survey indicated 17 million U.S. households, or 14.6% of all American households, were food insecure in 2008. To be food insecure, a household at some time during the year had difficulty providing enough food for all its members due to a lack of money or other resources. The prevalence of food insecurity was up from 13 million households, or 11.1% of all U.S. households, in 2007.

About 6.7 million food-insecure households, equating to about one third of food-insecure households and 5.7% of all U.S. households, had very low food security in 2008. In households with very low food security, the food intake of some household members was reduced and their normal eating patterns were disrupted because of the household’s food insecurity. The other two-thirds of food-insecure households obtained enough food to avoid substantial disruptions in eating patterns and food intake using a variety of coping strategies such as eating less varied diets, participating in federal food and nutrition assistance programs or obtaining emergency food from food pantries or emergency community kitchens.

The report indicated even when resources were inadequate to provide food for the entire family, children usually were shielded from the disrupted eating patterns and reduced food intake that characterize very low food security.

“However, children as well as adults experienced instances of very low food security in 506,000 households (amounting to 1.3% of all U.S. households with children) in 2008, up from 323,000 households (0.8% of households with children) in 2007,” the E.R.S. said.

The report reminded readers it was often the case that individual households did not experience very low food security year-round.

About 20% of food-insecure households obtained emergency food from a food pantry at some time during the year, and 2.6% ate one or more meals at an emergency kitchen in their community, the report indicated.

Prevalence rates of food insecurity were substantially higher than the national average (14.6% of all households) for households with incomes below the official poverty line (42.2% of such households were food insecure), households with children headed by single women (37.2%) or single men (27.6%), black households (25.7%) and Hispanic households (26.9%).

Food insecurity was more prevalent among households with children (21%) than among those with no children (11.3%). Among households with children, those headed by a married couple showed the lowest rate of food insecurity (14.3%).

In the case of households with very low food security, prevalence rates were lowest for married couples with children (4.1% of such households had very low food security), multiple-adult households with no children (3.8%) and households with elderly persons (3.1%). Very low food security was more prevalent than the national average (5.7%) for households with children headed by single women (13.3%), women living alone (7.7%), men living alone (6.8%), black and Hispanic households (10.1% and 8.8%, respectively), households with incomes below the poverty line (19.3%), and households located in principal cities of metropolitan areas (6.6%).

Children in households headed by single women were more likely to experience very low food security, as were children in households headed by a black or Hispanic person and those in households with incomes below 185% of the official poverty line.

The prevalence of food insecurity increased from 2007 to 2008 for all categories of households analyzed. Increases were the largest for single parents with children (both women and men) and for Hispanic households. The prevalence of very low food security also increased for all categories except for single-male-headed households with children.