The new enemy in the war against cancer and heart disease is dietary fat, a development that has weighed heavily on meat producers. Faced with declining sales and high-fat products to sell, the meat industry has been devising new ways to present both fresh and processed meats in a more healthful light.

il,7.6p But just how "lite" are these new "low-fat" meats? That depends on how you look at it.

Last October, Swift Independent Packing Co. of Chicago obtained U.S. Department of Agriculture label approval for a line of fresh pork cuts being marketed under the name "Swift Light." The company claims the product has 33 percent less fat and 25 percent fewer calories than its regular pork.

One of the reasons Swift's light pork is leaner is because the company trims the fat off the edges of this cut much closer thanxl it does its ordinary pork. Instead of the usual one-quarter to one-half inch of fat, Swift trims down to one-eighth of an inch.

That's something consumers can do in their own kitchens, but to really lower the quantity of dietary fat derived from the edible portion of the meat, intramuscular fat (or marbling) must also be reduced. Yet, the result of a large-scale survey released last week by the beef industry revealed that in the minds of many consumers, "leanness" means a low level of trimmable fat. For one test market, beef sales jumped when shoppers were given the option of buying a trimmer product.

Claims made by Swift for lower fat and reduced calories are based on the meat in its uncooked state. If USDA had required Swift to compare its regular and light pork after cooking, the company may not have been able to make the same claims. If cooked in the same manner, the difference in fat levels in the light and regular pork would shrink considerably; for example, USDA studies on regular versus lean ground beef found that the difference in fat levels before cooking was twice as much as after cooking.

Margaret O'K. Glavin, director of standards and labeling at the USDA's Food Safety and Inspection Service, says nutrition claims for meat generally are made for the state in which the product is sold -- for fresh meat, that means raw.

Swift is pricing its light line of pork at a premium, says Bill Dillman, manager of public relations at the firm, "because we're keeping the fat." He adds, "We'll pay a premium to hog producers for a lean hog." (The beef industry's research found that consumers were willing to pay a slightly higher price per pound for closely trimmed cuts, although not a markedly higher price.) Swift light pork will also require special shipping in an inert gas to prevent the cuts from aging too rapidly, which can happen when too much fat is trimmed off.

For an "old-line" traditional packing company such as Swift to venture into the marketplace with a specialized product is testimony to the consumer's desire for lower-fat products. "There was always a demand for low-calorie products, but up until a few years ago, it was the fringe," says Dillman, who noted that the company kills 9 million hogs each year and "we can't slow down for a fringe product."

"Things changed," he says. "People got concerned. It was worth listening to. Cholesterol and fat were getting a bad name, and rightfully so."

With fresh "light pork" on the market, "light beef" cannot be far behind. In fact, the USDA recently approved a "lite" claim for carcasses of the Chianina cattle breed. According to a study reviewed by the department, the Chianina crossbred has 25 percent less total body fat than a typical breed of cattle raised in the United States, the Hereford-Angus crossbred. A Texas firm, Chianina-Lite Inc., is planning to supply Chianina beef, under the brand label "Certified KEY-Lite," to restaurants and eventually through direct marketing.

Since the Chianina breed low-fat findings were publicized, Glavin says her division has received calls from other firms interested in pursuing a similar line of fresh products.

Gordon Davis, a meat scientist at Texas Tech University in Lubbock, conducted the study on the Chianina breed. He says the meat has about 40 percent less intramuscular fat and 10 to 25 percent fewer calories than a typical cut of beef graded "choice", even when trim levels are the same.

Cholesterol content, however, was found to be the same in both the regular and the low-fat beef, a finding that Davis says was a surprise to many who believed cholesterol content would decrease with fat content. In the study, Davis writes that his findings, along with similar findings from other studies, suggest that recommendations to consumers to eat lean meat in order to reduce cholesterol intake are "false."

Nutritionist Bonnie Liebman of the Center for Science in the Public Interest says consumers don't necessarily have to pay a premium for fresh meat labeled "light" to obtain lean meat cuts, so long as they stick to the naturally lean cuts of meats, such as pork tenderloin, round steak, flank steak, a good grade of chuck or sirloin, or a lamb foreshank. She adds, "There's no such thing as a truly lean meat. Even the leanest cuts get about one-third of their calories from fat."

To get a leaner cut of meat, it's necessary to start at the beginning: with the animal. Researchers from the USDA and in universities across the country are working on several fronts to find ways animals can convert more of their nutrients into muscle and less into fat:

*Genetic selection. Breeds of animals vary significantly in the amount of fat they deposit as they grow. The goal of researchers working in genetic selection is to develop lean breeds that produce good-tasting meat. Norman Steele at the USDA's Agricultural Research Center in Beltsville is conducting a population breeding study in swine and says he is making significant genetic progress feeding them high-protein diets and then pairing off parents for the next generation based on optimum body weight gain and minimum subcutaneous (under-the-skin) fat. Now on the fifth generation of swine, Steele hopes to carry the study to 10 generations.

*Hormone therapy. Researchers have discovered that growth hormones -- substances produced in the pituitary gland that are responsible for growth in animals and humans -- have a "very dramatic effect" on fat deposit when administered to livestock, according to Steele. They "literally cause the fat to melt down," he explains. Such hormones, which are now being genetically engineered, are not currently approved for use in food-producing animals. The first approval is likely to be sought for cows, because the hormone markedly increases milk production.

*Pharmacological agents. A potent class of drugs called orally active beta agonists has been found to simulate the action of naturally occurring adrenalin, in turn stimulating the removal or breakdown of stored fat. Safety studies would have to be performed on the drug before government approval could be sought.

*Feeding strategies. What, when and how animals are fed affect fat deposit. For example, differences in fat levels have been discovered simply in the physical form in which feed is offered, such as mashed versus pellet. High-protein diets appear to produce leaner animals, according to Steele, as do high-fiber feeds. In the United States, feed is always available to the animals, but some studies suggest that specific feeding periods -- in other words, breakfast, lunch and dinner -- may produce a leaner animal.

"Basically," says one USDA researcher, "we're overfeeding our animals." But U.S. producers have not been able to develop a delivery system to limit feeding without significantly raising labor costs.

Over the years, animals have been bred for leanness -- hogs are 40 percent leaner today than 20 years ago, according to Steele. Most of this reduction in swine has been in subcutaneous fat, and for a practical reason: Animal fat is no longer the useful commodity it once was, when it was sold for production of lard, soap and grease. "We're still interested in making more progress," says Roger Gerritis, national program leader for animal production at the USDA's Agricultural Research Center. "But there will be some physiological limit."

There is also a market limit. Fat gives meat flavor and tenderness, especially in beef. Studies of ground beef conducted by Bradford Berry at the the USDA's Meat Science Research Laboratory in Beltsville found that when fat level was reduced to 10 to 12 percent by weight, the product was "a lot drier," Berry says, and less tender and flavorful.

Even without the hormonal and pharmaceutical agents of the future, it is possible today to produce an extremely lean carcass through breeding and feeding practices, says the USDA's Steele. Yet the USDA's own grading system acts as a disincentive to producers to raise lean animals, because meat carcasses with more marbling are awarded higher grades and fetch higher prices at the market. The system appears to contradict the results of the beef industry's consumer survey, which found that "quality" to a large segment of consumers means a lean cut of meat.

A coalition of public interest groups says the Department of Agriculture's current policy on "lite" labeling of meat and poultry products is an affront to the English language.

In a petition filed last November, the groups charge that the policy "fails to make any distinction whatsoever" between the terms "lean" or "extra lean" and "low fat" or "lower fat" on meat and poultry product labels.

The USDA's current policy, issued in May 1984, works like this: You are a meat processing firm and you want to put out a "light" sausage to compete with similar products on the market. How much fat do you cut out? You have a choice. You can lower the amount of fat by 25 percent, in comparison with one of the following standards:

*Your regular sausage line.

defbox The amount of fat in a leading competitive brand.

*The average amount of fat in competing brands based on a market-basket survey.

*The maximum amount of fat allowed by the USDA standard of identity for the product.

*The average fat content of similar products listed in the USDA's nutrient composition data.

The USDA does require a declaration of the fat content on the label, along with a statement explaining the standard against which you are comparing the product, such as "25 percent leaner than our regular pork sausage." Once you've made those statements, you have a choice of terms for your sausage label: lean, leaner, extra lean, low fat or lower fat.

While this alone may sound complicated, there's more. You can also choose the term "lite," but lite could refer to sodium or breading content as well as or in addition to fat.

The USDA policy "stands reason on its head," says the petition, filed by the Center for Science in the Public Interest, the New York state attorney general, the American Heart Association, the American Public Health Association, the Consumer Federation of America and Public Voice for Food and Health Policy. "It's a joke," Liebman of the CSPI says of the USDA labeling policy. "It's basically you say whatever you want."

As the petition illustrates, the five standards by which to indicate lower fat content can vary widely. For example, the USDA's standard of identity for sausage permits a maximum of 50 percent fat by weight. However, in the department's nutrient composition data, know as Handbook No. 8, sausage averages 40 percent fat by weight. Some leading brands, such as Eckrich Skinless Smoked Sausage and Klement's Fresh Sausage, contain 25 percent fat by weight.

The result: a product such as Bob Evans fresh pork sausage, which is 34 percent fat by weight, could make a "lean" claim under the USDA's policy because it has 25 percent less fat than the USDA standard of identity. Yet it has only 15 percent less fat than the USDA average and 36 percent more fat than some leading brands.

"The department has given meat and poultry companies discretion to choose virtually any definition that meets their own marketing needs, and left consumers and producers of truly lean products wading through a morass of confusing and sometimes conflicting label claims," the petition charges.

The groups also complain that the policy allows foods high in fat to bear low-fat claims. Among such products cited in the petition are Oscar Mayer's Lean 'n Tasty Pork Stripes (35 percent fat by weight and 71 percent of calories from fat); Beatrice's Sizzlean Beef Breakfast Strips (35 percent fat by weight and 71 percent of calories from fat), and Eckrich's Lean Supreme Jumbo Franks (20 percent fat by weight and 64 percent of calories from fat).

George Wilson, director of scientific affairs at the American Meat Institute, which represents meat processors, says there are areas in the USDA's current labeling policy that could be improved, such as differentiating between the terms "lean" and "extra lean." However, he emphasizes that the policy does require a declaration of fat content and a comparative statement explaining the standard chosen by the company. The policy "certainly has encouraged people to step out and introduce products with less fat," Wilson points out. "In that regard, it has been a positive move."

Under a labeling scheme proposed by the coalition of consumer groups, products with a fat content not greater than 10 percent could be labeled "lean," while those with a fat content of no more than 5 percent could be labeled "extra lean." Products with at least one-third less fat than one designated standard could be labeled "lite."

The petition is "under active review," says John McCutcheon, deputy administrator for technical services at the USDA's Food Saftey and Inspection Service. "I think they've raised some good points."

The petition asks that nutrient data from USDA's Handbook No. 8 be the standard by which fat content is lowered. If the food is not listed in the handbook, the groups suggest, then market-basket survey data could be substituted. However, McCutcheon contends that requiring firms to conduct such a survey may be unreasonable and put smaller firms at a competitive disadvantage.

Along with the issues involved in changing its labeling policy on low-fat products, the USDA has under consideration a petition from the American Meat Institute asking the department to develop a standard for "lite" cooked sausage. The current standard for cooked sausage, which includes frankfurters and bologna, limits the amount of water processors can add to 10 percent by weight. The meat institute contends that this requirement stymies processors, because cutting back on fat without adding extra water makes for a dry, unpalatable product. The petition asks the agency to set a minimum protein content for "lite" sausages of 11.5 percent and to permit processors to add as much water as they want.

Would consumers then be getting "water dogs" instead of hot dogs? The meat institute's Wilson says no. "Moisture, protein and fat must be kept within a reasonable balance to make a reasonable product," he says, noting that even if processors were able to produce a frankfurter high in water, "it wouldn't be accepted by the consumer as a hot dog."

The CSPI believes a separate "lite" sausage standard is unnecessary, because some companies are already manufacturing such products without exceeding the 10 percent added-water limit. However, if the USDA does grant the meat institute petition, the group told Food Safety and Inspection Service Administrator Donald L. Houston in a letter last summer, the agency should require labeling of nutrition and fat content. If the meat institute had its way, meat processors producing "lite" sausages under the proposed standard would not have to include such information on the label.