The House and Senate agriculture committees are holding hearings this week on reauthorizing SNAP (the Supplemental Nutrition Assistance Program, formerly known as Food Stamps) and could cut assistance by $20 billion over the next five years.

At last count, about one in five Americans received food stamps, many of them elderly or working-poor families with children.

The Congressional Budget Office found that about two-thirds of the increase in spending on benefits between 2007 and 2011 reflects higher program participation due to the economy.

"The primary reason for the increase in the number of [SNAP] participants was the deep recession from December 2007 to June 2009 and the subsequent slow recovery; there were no significant legislative expansions of eligibility for the program during that time," they said.

Meanwhile, a seperate study by the U.S. Department of Agriculture (USDA), which oversees the federal food stamp program, looks at what participants eat and found that it's not that different from those not in the program.

Judi Bartfeld is a professor of consumer science at the University of Wisconsin-Madison. She was not part of the study, but says research on SNAP, commonly known as food stamps, shows it does reduce food insecurity. However, studies to date have not shown a major improvement in what's eaten.

"When people get SNAP, they tend to eat a little better with regard to certain aspects of their diet. They might eat a little worse with regards to certain other aspects. But there just don't seem to be any major differences. I think most of the research in this area has found pretty marginal impacts in terms of actual diet quality."