WASHINGTON - Hundreds of thousands of unemployed or underemployed Americans will be dropped from a federal food aid program under a rule change announced by the U.S. Department of Agriculture.

The new policy, approved on Wednesday as part of a package of proposed changes, would pressure states to implement work requirements for able-bodied adults without children at a time of low unemployment, instead of requesting a waiver. Until now, many states have been allowed to waive the work requirement because of the difficulty many food stamp recipients have encountered in finding employment in economically distressed areas.

USDA Chief: Change to Federal Food Aid Program Will Help 'Restore Dignity of Work'

Sonny Perdue, the U.S. secretary of agriculture, said the changes are part of the administration's plans to "restore the dignity of work to a sizable segment of our population" and save taxpayer dollars. The rules change is estimated to save $5.5 billion over the next five years.

USDA Chief: Change to Federal Food Aid Program Will Help 'Restore Dignity of Work'

"Of the 3 million able-bodied adults without dependent children currently getting food stamps," said Robert Rector of the conservative Heritage Foundation, "only about a third of them would be subject to this [USDA] work requirement."

USDA Chief: Change to Federal Food Aid Program Will Help 'Restore Dignity of Work'

However, critics say the government is weakening a program that acts as a social safety net for millions of Americans. Individuals 18 to 49 years old without children are unable to qualify for other welfare programs.

"The Trump administration is abandoning this longstanding, bipartisan practice … and replacing it with a much more restrictive rule that will increase hunger and destitution," said Robert Greenstein, president of the Center on Budget and Policy Priorities, a liberal research institute.

USDA's latest estimate is that 688,000 unemployed or underemployed individuals will fail to qualify for food aid from the Supplemental Nutrition Assistance Program (SNAP) under the changes to the waiver system.

SNAP is also known as the food stamp program, although recipients now receive debit cards that can be used in place of money to buy food. The average recipient of food stamps received $127 a month, or $4.17 a day, in fiscal year 2018.

Currently, able-bodied adults without children living in states without waivers can receive food stamps for no more than three months out of a three-year period without getting a job or participating in a job training program. States are allowed to grant waivers to people in areas that are economically distressed and have an inadequate job supply.

But under the new rule approved by the Agriculture Department, an area would have to have at least an average unemployment rate of 6%, and also be 20% above the national average for a 24-month period.

While technically the 688,000 participants are not going to be kicked out of the stamp program, the areas they live in will not be able to qualify for waivers to allow them to stay on the program.

During fiscal 2018, an estimated 2.9 million able-bodied adults without dependents were participating in the food stamp program.

SNAP allows poorer households that are below the U.S. poverty line to buy fresh groceries and other goods. Households and individuals closer to the poverty line receive less than poorer households and Individuals.

Those who are able to work must work or participate in training programs or a combination of the two — for a total of at least 80 hours a month, or 20 hours a week.

The USDA excuses adults who are pregnant or who have mental or physical disabilities who are unable to work.

Families, the elderly, and the disabled also have different requirements and will not be affected by the changes.

States can ask for waivers for specific areas or the entire state to waive the work requirement for adults without children. Waivers were implemented in numerous states for areas that contained around 40% of the U.S. population in 2017, according to data from the Center on Budget and Policy Priorities.

The Food Stamp Act was implemented as part of President Lyndon Baines Johnson's "War on Poverty" in the 1960s.

In the 1990s, there was a bipartisan effort in Congress to change the requirements for receiving government food stamps, resulting in the Personal Responsibility and Work Opportunity Act of 1996 that required work in exchange for time-limited assistance.

In 2018, Republicans in Congress attempted to amend the 2018 Farm Bill, an expansive omnibus bill that covers most of U.S. agriculture, to change SNAP and reduce the number of recipients.

The House rejected the GOP SNAP changes in a bipartisan vote of 330-83, and the Senate voted down a similar amendment, 68-30.