Cabinet secretaries, it seems, can be pushed only so far. In an hour-long news conference yesterday to announce the government's new dietary guidelines, Health and Human Services Secretary Louis W. Sullivan and Agriculture Secretary Clayton Yeutter amiably fielded questions and criticisms about the government's new dietary guidelines.

Until the cafeteria issue came up. Then they got a little ornery.

"As some of you may have noticed, The Washington Post did an article this morning evaluating government cafeterias," Yeutter said, referring to a Federal Page review of four leading federal eateries. "And the opening line on our USDA cafeteria, which is just down below us one floor, was that it had the ambiance of a Nebraska feedlot.

"And I wanted you all to know that I considered that to be the highest compliment. Being from Nebraska, we think the ambiance of a Nebraska feedlot is a very special thing."

Sullivan appeared to take a more serious view of the review. The reporter, he said, was "anxious to find critical issues" but "failed to get the point that we are providing information and choices to our employees."

"We have introduced and are encouraging the adoption of healthy diets, lower consumption of fat, and it so happens that we commissioned an outside consulting agency to follow the eating patterns of our employees using that cafeteria, and we have shown remarkable decreases in consumption of foods heavy in fat content and an increase in foods that are healthy," Sullivan said.

Added Yeutter: "And I want you to know that two floors above is the secretary's dining room, which serves soup and very healthful salads, and just across the way in the other building is the USDA Fitness Center, so if any of you reporters want to come over and work out before you go back to your offices, you're welcome."