ENROLLMENT in the food-stamp program, the nation's major anti-hunger plan, has surged to its highest level in five years, but there is no simple explanation for the increase. In the past, participation rose or fell depending on the unemployment rate. But officials noted Monday that some months ago the linkage was not as direct as it once had been.
According to the government's most recent figures, about 20.1 million people are receiving food stamps, up 1.3 million from one year earlier. By comparison, the administration forecast an average of 19.3 million people would receive benefits during the current fiscal year.
The food-stamp program helps poor people improve their diets by supplementing their food-buying power. The maximum benefit for a family of four this fiscal year is $331 a month.
``What is remarkable about the recent growth in participation is that there is no consensus about its cause,'' says an Agriculture Department report to the Senate Appropriations Committee.
``It occurred even though there were no major changes in the [program] or in the economy, at least as measured by the national employment rate.''
The Agriculture Department, which administers the food-stamp program, says its analysis suggests three factors - expansion in Medicaid, state-level changes in joblessness, and legalization of undocumented aliens - accounted for between 25 percent and 43 percent of the increase.
``A large group of other factors might be responsible for the remaining increase,'' the report says.
The chairman of the House Select Committee on Hunger, Rep. Tony Hall (D) of Ohio, takes a different view. He says higher enrollment showed the fragility of the conditions of many Americans, so that a slight weakening in the economy stretched many incomes too far.
In addition, Representative Hall says, people were forced to turn to public food programs because contributions of private organizations have diminished.
The House has authorized $19 billion for food stamps in fiscal 1991, about $2.2 billion more than the White House requested. The Senate has yet to act.
In addition to allocating funds, Congress also must reauthorize the food-stamp program this year. The House has voted to phase out the current limit on how much can be deducted for housing costs and to allow participants to own vehicles worth up to $5,500 without losing eligibility for the program.
In its report, the Agriculture Department says participation levels are up in 44 states and the District of Columbia. Texas, California, and Florida account for nearly half of the nationwide increase.
However, the report notes that jobless rates are down in Texas and Arizona, despite those being two of the 10 states with the largest increases in enrollment.
It appears, the report says, that most of the increase in enrollment came through more people entering the program, rather than people receiving benefits for a longer period of time.
The department's Economic Research Service, in an analysis published early this year, said one of seven Americans participated in the food-stamp program during a one-year period, but most receive benefits for less than 12 months.
Studies have found the program means a 5 percent to 10 percent increase in spending on food by poor households.