President Reagan, speaking before members of the armed forces' elite honor guard units yesterday in a mess hall at Arlington's Fort Myer, vowed to fight a House-approved defense budget that he called "wholly inadequate" to allow the continued revitalization of the military.

During his weekly radio address, broadcast live before an audience of 120 honor guards as part of the 37th annual observance of Armed Forces Day, Reagan said the House budget measure is "a throwback to the '70s" and a "breach of faith with our armed forces and our allies."

On Thursday, the House approved a budget that is $35 billion shy of Reagan's defense spending proposal.

After yesterday's five-minute address, the president quickly turned to other matters. "I'm hungry," Reagan said as he filed through the chow lines with the enlisted men and women.

Reagan spent nearly an hour lunching with the honor guards, who serve in the military displays during the visits of foreign leaders and other formal events, such as state funerals.

Afterward, Airman First Class Sheri L. Heck, who sat next to Reagan as he ate roast beef, salad and apple pie, said the president continued to talk about his displeasure with the military spending proposals.

"We all basically agreed it was bad," said Heck, a 21-year-old from Houston who is based at Bolling Air Force Base in Southeast Washington.

Heck said she did not know she was assigned to sit next to Reagan until she arrived at Fort Myer. "I can't believe that I got to eat lunch with the man I admire most in the whole country," she said.

Representatives from local Army, Navy, Air Force, Marine and Coast Guard installations were on hand for the presidential visit, during which Reagan lauded the group, calling them his uniformed "grandsons and granddaughters." He said the nation's military is "better trained, better educated and more motivated" than in the past.

"Thank you for being there . . . for keeping America free and at peace," Reagan said.

Reagan also praised the two pilots who were lost during the recent bombing of Libya.

"We owe a great debt to those on freedom's first line of defense, men like Capt.[Paul] Lorence and Capt. Fernando Ribas-Dominicci," he said. "We honor them today and all the members of freedom's honor guard."