Food banks across the country say the demand for food has spiked in the last several years, thanks to the weak economy.

New census estimates show the number of Americans living in poverty is higher than previously thought.

Forty-nine million people, or 16 percent of Americans, now fall in that category.

New research shows that many of these people have shifted from using local food pantries as a temporary fix to help their household budgets -- to using them on a long-term basis as a source of food for their families.

CBN News spoke to Ross Fraser, the media relations director at Feeding America, the nation's leading domestic hunger relief charity. The group supplies food to thousands of pantries across the country.

Fraser explained that over the past couple of years, the demand for food has gone up dramatically.

"Five years ago, we were moving shy of 2 billion pounds of food a year. Today we're going to deliver in 2011, 3.3 billion pounds of food. So that's a billion more pounds of food in four short years. That's a tremendous increase," he said.

"And we've accessed that food because we've had. to find new ways to get new food because there's so many people at risk of hunger," Fraser added.

CBN News visited several food pantries in the Chicago area this past weekend to examine the problem in the Windy City. Watch Heather Sells' report from the CBN News Channel's Midday News, Nov. 7.