Some of the 40 million Americans who eat in fast-food restaurants each day will soon find out what's in the beef. In July, Burger King and Wendy's restaurants across the nation plan to provide brochures that list food ingredients. McDonald's and Roy Rogers will also offer ingredient pamphlets but will limit them to New York outlets.

Many fast-food items have some ingredients, such as monosodium glutamate and yellow dye No. 5, that can trigger allergic reactions. Others contain high levels of cholesterol, sodium and fat, which can contribute to heart disease. Industry spokesmen say the food is nutritious, but consumer advocates say it poses health risks. The need for ingredient disclosure in fast-food chains is hotly disputed. Consumer advocates and several legislators say disclosure would allow restaurant patrons to select more healthful meals and enable people with allergies to avoid certain substances.

Disclosure would also prompt chains to use more wholesome ingredients, said Michael Jacobson, director of Center for Science in the Public Interest. McDonald's and Burger King's recent switch from beef tallow to vegetable oil for frying foods is an example of this, he said.

"Americans have the right to eat healthy or unhealthy foods, but they also have the right to know what they're consuming," said Rep. Stephen J. Solarz (D-N.Y.), who recently introduced legislation requiring fast-food chains to provide ingredient information. The bill, identical to one proposed by Sen. John H. Chafee (R-R.I.) last month, would require restaurants with 10 or more outlets to list ingredients on food wrappers or on a wall poster.

But most industry spokesmen oppose such legislation. Some say consumers have no appetite for ingredient information. Others favor voluntary use of brochures and say that printing information on wrappers is not only costly but impractical.

"With the thousands of combinations of condiments and foods, what would we do? Consumers would need a magnifying glass to read the tiny print on a wrapper," said Wendy's spokeswoman Linda Packer. "We would have to re-do all the packaging and that cost would be passed on to the consumer. Would consumers want to pay a nickel more to read that their burger is made of beef?"

Current law requires that packaged foods sold in grocery stores list ingredients. Last summer, CSPI asked all 50 states to apply the existing packaged food labeling laws to fast food as well. So far, only New York Attorney General Robert Abrams has responded.

Abrams asked fast-food chains to voluntarily supply information to New York residents. McDonald's and Roy Rogers officals agreed recently to make information available within the state for one year on a trial basis. Wendy's and Burger King representatives say plans to provide ingredient brochures nationwide were already under way.

"But I don't see how brochures will change anything," said Burger King representative Jo Hutcherson. "People aren't expecting us to be a health food store."

Nora Zamichow is a writer living in New York who frequently contributes to Health.