Sen. George McGovern (D-S.D.), a legislative champion of the well-rounded diet, yesterday pulled a switch of sorts and became a recruit in the army of Ronald McDonald.

Beyond the kind words for the familiar hamburger chain, McGovern gave his unqualified support to the $20 billion fast food industry as a wholesome and vital contributor to American stomachs.

Some dietitians might blanch, but McGovern said he thought it was time to put to rest the image of fast foods having "little or no nutritional value."

"I and a lot of other people have given them a bad rap. The truth is that you may be better off nutritionally than you would be at some fancy gourmet restaurant," he said.

The country's biggest and best-known fast food franchisers could not have said it any better, and, in overn's Agriculture subcommittee on nutrition.

Actually, they were there to offer their thoughts on federal regulators' efforts to require them to label more clearly the content and nutrition value of their fried and batter-dipped and super-creamy goodies.

Spokesmen for Kentucky Fried Chicken Corp., McDonald's and Pizza Hut took turns lambasting the Federal Trade Commission and the Food and Drug Administration for their moves toward more explicit labels.

The National Restaurant Association and the Food Service and Lodging Institute joined in complaining that labeling efforts would add huge new costs while not giving consumers that much new and vital information anyway.

McGovern and Sen. Bob Dole (R-Kan.), the only other subcommittee member present, agreed with the witnesses. They indicated they will see what they can do to help prevent labeling requirements that go beyond "common sense."

Common sense, as outlined by Pizza Hut Vice President Gerald T. Aaron, should not go beyond what his chain already does -- posting nutrition charts on the walls of their pizzerias.

McDonald's vice president, Norman D. Axelrad, said his chain thinks that its customers are entitled to nutrition information, but that to require a label on every Big Mac would be excessive.

His description of the fresh, wholesome, government-inspected ingredients of the McDonald's menus led McGovern to rhapsodize slightly about the great American hamburger.

The senator noted that Ronald McDonald, the chain's clown symbol, had set a recognition record that makes politicians envious -- 96 percent of U.S. schoolchildren know who Ronald is.

McGovern said he had been guilty of equating the menu of the fast food restaurants with "junk food," and only recently got religion when he learned more about the McDonald's ingredients.

"Fast food is not inferior food. It is not fair to imply the food is inferior because it is prepared swiftly," he said.

Axelrad, AAron and Dr. John B. Mann of Kentucky Fried Chicken suggested that the moves toward government regulation of labeling actually have had a "chilling effect" on voluntary corporate efforts to provide consumers with more information.

Axelrad said McDonald's has been reluctant to move because of a fear that any informational efforts or nutrition market tests might trigger even broader FDA requirements or interpretations.

Kentucky Fried Chicken's Mann said a label simply won't work on wings, backs and drumsticks. Each of those chicken parts is different in size, he said, and there's no way a uniform nutrition label could apply.

Mann and his fellow witnesses urged the McGovern subcommittee to pick out one federal agency to oversee nutrition information and eliminate confusing overlapping that now exists.

The FDA and the FTC are in the preliminary stages of preparing nutrition label proposals that might apply to the foods served in restaurants. McGovern said his subcommittee intends to call in agency officials to discuss the subject further in the interest of "common sense"