"Where's the beef? It's in the fries," chanted the group of about 25 protestors outside the McDonald's on K St. Thursday, a few dressed as french fries with slices of sponge "potatoes" slung around their waists. The beef in the fries is beef tallow, the type of saturated fat that McDonald's and six other fast-food restaurants use to fry their french fries, according to the Center for Science in the Public Interest.

It is also the type of fat that promotes heart disease by raising blood cholesterol, according to doctors William Castelli, medical director of the Framingham Heart Study, and Tazewell Banks, professor of medicine and director of the heart station at D.C. General Hospital. At a press conference preceding the demonstration, Castelli and Banks joined CSPI in urging fast-food restaurants to disclose the type of fat they use through mandatory ingredient labeling, to fry foods in unsaturated fats and to offer more lowfat broiled and baked items. In addition, approximately 125 scientists and physicians, including 10 deans of medical and public health universities, signed a petition to the Food and Drug Administration in support of Castelli's, Banks' and CSPI's stand.

While the consensus in the scientific community recommends limiting consumption of saturated fats, there are some scientists who challenge these dietary recommendations. "The idea that saturated fat and cholesterol causes heart disease is just wrong," said Dr. George Mann, professor of biochemistry at the Vanderbilt School of Medicine. "We ought to be looking for the proper explanations," said Mann, who added that such recommendations are being perpetuated because they are profitable for government-funded research scientists and food companies, such as those who produce vegetable oil.

Mann also said that polyunsaturated acids may have problems of their own. Ongoing research has shown that they stimulate peroxides in the tissues, which can lead to malignancies, he said.

Frank Sacks, an associate professor at Harvard Medical School, conducted the fast food analysis, which included collecting french fries from 19 chains. The restaurants that fry their fries in beef tallow (often mixed with a little vegetable oil) include Arby's, Bob's Big Boy, Burger King, Hardee's, McDonald's, Popeye's and Wendy's. Howard Johnson's uses palm oil, a highly saturated vegetable fat.

The chains that use vegetable oil include Denny's, Friendly's, Papa Gino's, Church's, D'Lites, Kentucky Fried Chicken, Long John Silver, Red Lobster and Rustler.

McDonald's spokesperson Terry Capatosto said the chain uses beef tallow for both its fries and Chicken McNuggets because it produces a "higher quality" and better tasting product. Capatosto said that McDonald's has no plans to change the oil.

Joyce Myers, spokesperson for Burger King, a chain that uses a combination 90 percent beef tallow/10 percent vegetable oil to fry its fries, onion rings, fish and chicken sandwiches, said that consumers prefer the taste of beef tallow, but that Burger King is looking at less-saturated oils. Myers said that the animal/vegetable shortening costs less than corn or soybean oil.

Patrons leaving McDonald's while protestors chanted "give us relief, cut out the beef," had a mixed reaction. One said he might "check out the delis" in the area instead, another that "people know that cigarettes cause lung cancer, but they still smoke."