Legislative changes to the National School Lunch Program in 1980 and 1981 tightened eligibility requirements for schools and students and reduced the Federal reimbursement rates for free, reduced-price, and full-price school lunches. The U.S. General Accounting Office analyzed participation and Federal expenditures for the 1979-83 period and found: (1) Student participation declined from 27 million to 23.1 million primarily because fewer students ate full-price lunches. In 1982 for the first time in the history of the program, more free and reduced-price lunches were served than full-price lunches; (2) The drop in participation by schools and students in the program slightly outpaced the drop in the number of schools and student enrollment nationally; and (3) Federal program expenditures were greater in 1983 than at any time except 1981, the peak year. Since 1979, the number of families with children qualifying for free lunches increased as did the percentage of Federal expenditures for free lunches. Federal expenditures for reduced-price and full-price lunches decreased. (Author/CJM)