Suppose you want to market a sausage pizza with less fat. So you decide to use less sausage. Good luck. The federal government requires that a sausage pizza contain at least 12 percent cooked sausage by weight. You either have to use that much meat, or call the product something else. Pizza with Tomato Sauce Flavored with Sausage is not exactly a grabber.

Known as standards of identity, there are hundreds of government rules about the maximum or minimum amounts of certain ingredients in food products. Recipes written in government-ese, they define foods and prescribe the mandatory and optional ingredients they can contain. If a product deviates from the standard, it can't be called by the standardized name. So Reduced-Fat Sausage Pizza wouldn't be acceptable.

You want to manufacture schickenwurst, jagdwurst, knishes or kishke? The U.S. Department of Agriculture has a required recipe. The USDA, which regulates meat and poultry products, sets standards for everything from goulash ("at least 25 percent fresh meat ... product may be just meat and gravy or meat and gravy with vegetables served with, without or combined with rice, potatoes or noodles") to meat balls ("at least 65 percent meat, up to 12 percent extenders and binders permitted, hearts are not allowed ... "

The Food and Drug Administration, which regulates everything else, sets minimum fat standards for cheeses, from asiago to Swiss. The agency's standards also dictate to manufacturers the amount of peanuts in peanut butter (90 percent by weight), how many apricot pits are permitted in canned apricots (one for every eight ounces) and how finely ground farina should be (thin enough to pass through a No. 20 sieve, but not more than 3 percent can pass through a No. 100 sieve).

Standards of identity were devised to protect against economic fraud, but as dietary priorities have changed, some of these standards -- specifically the ones that set requirements for fat or meat content -- are being questioned.

Before there were rules for minimum fruit and maximum sugar contents of jams and jellies, for example, many of them had little fruit and lots of starchy stretchers. And because a senator years ago complained about the lack of cherries in his cherry pie, there is now a requirement that the drained cherry content of a frozen cherry pie be not less than 25 percent of the pie's weight, according to FDA.

Nowadays, however, some food companies, health authorities and consumer groups contend that the standards are stifling and inhibited some manufacturers from marketing lower-fat, healthful products because they are prohibited from calling them by their familiar names.

If a manufacturer wanted to make a meat lasagna, but wanted to reduce the fat by lowering the meat content, the company might be able to call the product Lasagna With Meat-Flavored Sauce, said Gary Kushner, a food lawyer and partner at Hogan & Hartson. "But a manufacturer isn't going to do that. It's just not appealing from a marketing standpoint."

Take the case of the ham and asparagus pot pie. There is no USDA standard for the product, but there is a standard for meat pot pies -- they must contain at least 25 percent meat. Nevertheless, a company that wanted to market this alternative pot pie wanted to lower the fat by using less ham. The USDA, which has preapproval for all meat and poultry labels, responded with the following four options for the name of the product:

1) Imitation Ham and Asparagus Pie, 2) Ham and Asparagus Pie -- Contains 19 Percent Ham Where USDA Requires 25 Percent Meat, 3) Ham and Asparagus Bake -- Sauce With Ham and Asparagus Topped with a Crust or 4) Asparagus Casserole Flavored with Ham and Topped with a Crust.

The sausage pizza scenario described previously actually happened to Stouffer Foods, which wanted to make a Mexican-Style French Bread Pizza under its Lean Cuisine line. It formulated a recipe that focused less on seasoned meat and more on tomato salsa and vegetables. But it only had 8 percent meat, less than the USDA's required 12 percent for sausage-topped pizzas.

Since it was very important to Stouffer's to be able to call the product "pizza," it ended up reformulating the recipe and increasing the meat. The resulting product, which is being test marketed this month, "still has a good nutritional profile," said Roz O'Hearn, spokeswoman for the company. "But we originally had a better nutritional balance with 8 percent."

Stouffer's believes that the USDA is cooperative and good at trying to reach a common ground. "We are not precluded from making healthy foods," O'Hearn added. But "a certain element of frustration creeps in. To create a healthy food and be able to market it, it's important to call it something the consumer understands."

Ellen Haas, director of the advocacy group, Public Voice, supports an overhaul of food standards. "Our definitions and values have changed as we've learned more about the relationship between diet and health. Industry can produce products that meet the health objectives, but our regulatory system is still archaic."

Still, some food producers and processors are in favor of supporting the status quo because they believe current standards maintain product integrity, help identify and market the food and prevent competition with products they believe have inferior characteristics. In order to reach compromises within the industries, the FDA would have had to deal with long drawn-out hearings to change existing standards, according to an FDA spokesman. "FDA was faced with expending a lot of resources on issues that were not acute public health problems," he said.

Nevertheless, the spokesman pointed out that the new labeling law that was passed by Congress in October gives the agency much more flexibility when it comes to changing or adding standards. Under the new law, standards may be changed or new ones can be written with faster administrative procedures. The only exceptions are dairy products and maple syrup standards, which must still undergo the same lengthy process to be changed.

At the very last minute, Sens. James Jeffords (R-Vt.) and Herbert Kohl (D-Wisc.), representing producer interests within their states, got the exemptions tacked onto the bill. Dairy farmers are concerned that if standards are easy to change, there will be a plethora of low-fat dairy products on the market, and no place for them to sell the excess milk fat, according to Ed Coughlin, director of regulatory affairs at the National Milk Producers Federation, a group that represents about 60 percent of the country's dairy producers. They also fear that a surge in lower-fat products that use water or other non-dairy ingredients to replace milk fat would reduce the demand for milk.

In a move last month that was hailed by consumer groups and the ice cream industry, the FDA requested comments on changing and creating new standards of identities for ice cream. For a product to be called ice cream, it would still have a minimum of 10 percent milk fat, but "reduced-fat ice cream" would replace "ice milk" and fat standards would be established for low-fat and nonfat ice cream. Currently, these kinds of reduced-fat products have been lining freezer cases with names such as "frozen dairy dessert."

In addition, the U.S. Department of Agriculture last week released a detailed plan of its intentions to require mandatory nutrition labeling for meat and poultry products. As part of the plan, the agency states that it will reassess its standards that require minimum amounts of meat and poultry.

"These are not insurmountable," said Bob Gonter, associate deputy administrator for regulatory programs at the USDA's Food Safety and Inspection Service. "We think we can come up with something in the end." The main question, the USDA said, will be how to prevent economic adulteration while still providing lower-fat products.

In the meantime, supermarket shelves are filled with a jumble of product names. Dairy products are a case in point. Some companies have taken the plunge and named their cheeses "Reduced-Fat Muenster," for example, even though standards technically don't allow it, while other firms have chosen names such as "Muenster Cheese Alternative."

Kraft/General Foods has gotten several warning letters from the FDA over the past few years for the labeling of some of its dairy products. The company has a line called Kraft Light Naturals, for example, with names such as Reduced Fat Swiss Cheese. FDA standards require that in order to call a product Swiss cheese, it must have a minimum of 43 percent milk fat. The Kraft product has a third less.

FDA also complained about the firm's reduced-calorie mayonnaise and cholesterol-free mayonnaise. To call a product mayonnaise, it must contain eggs and at least 65 percent by weight of vegetable oil.

Ed Thompson, chief food and drug counsel for Kraft/General Foods, said "we're trying our best to provide consumers with nutritionally modified versions of traditional products, recognizing the positions of the health authorities. In order to do that, you have to provide nomenclature which allows the consumer to identify the product." In the case of Kraft's Light Naturals Reduced Fat Swiss Cheese, Thompson said, "I don't think it purports to be Swiss cheese. It's just the opposite. We hope consumers don't think it's regular Swiss cheese or we'd be failing to market it as a reduced-fat version."

What adds to the marketplace confusion is that the FDA does allow companies to deviate from the standard if they apply for what are called "temporary marketing permits." These allow the marketing under the standardized name of a product that differs from the standard for a given time period, as a sort of test market. For example, Giant Food was granted a TMP for Light Ice Cream and Light Sour Cream, as were several other companies. During the holidays, FDA granted several permits for Light Eggnog.

In addition, several states have different standards. California and Wisconsin, for example, have definitions for reduced-fat cheeses, and in August, the Minnesota state legislature created a standard for light butter.

In fact, Sen. Robert Kasten (R-Wisc.) unsuccessfully attempted to get a federal statute for light butter through the last session of Congress. Unlike other standards set by the FDA and USDA, the definition of butter was set by Congress in 1923 under the National Butter Act. Under that law, butter must contain at least 80 percent milk fat.

The interest in light butter stems from a new product made by Land O'Lakes. John Bumbalough, group leader for research and development for the firm, said that the product contains 52 percent milk fat, and that the fat replacement is mostly water. It is currently being sold to food service operators in Minnesota, but the state's consumers should start seeing it on supermarket shelves by next month, he added.

The product could be available nationally if Land O'Lakes chose to call it a "dairy spread." The company considered that name, Bumbalough said, but market research indicated that the term was "meaningless to consumers. Light butter is not."

Kasten's bill would have set light butter at 52 percent milk fat, a restriction that did not please companies such as Johanna Farms, a subsidiary of Canada's John LaBatt Inc. That company is currently marketing a light butter product in Canada with 40 percent milk fat.

Aside from the standards of identity that deal with fat and meat minimums, there are some quirky, seemingly arbitrary standards that were set based on what was being sold at the time, or as a response to an industry request.

For example, there's a standard for French dressing, but none for any other dressings. That means that technically companies are not permitted to call a product Low-Calorie French Dressing because it deviates from the standard, but they would be permitted to call a product Low-Calorie Italian Dressing since there is no standard for Italian dressing.

There are also standards for low-sodium cheddar and colby cheeses. But to sell a reduced-sodium version of Swiss, a company would have to call it something like Low-Sodium Swiss Cheese Alternative. And in the great black hole of ice cream, there is no standard (or name, obviously) for products that have between 7 and 10 percent milk fat.

When it comes to fruit cocktail, manufacturers are required to include maraschino cherries. Last year, one company, suspecting some consumers might not want to eat the chemically dyed cherries, asked for a temporary marketing permit to sell Fruit Cocktail Without Cherries. The permit was granted, but not without opposition.

In a heated letter to the FDA, Tri Valley Growers, a competitor, wrote "there is certainly no compelling reason why fruit cocktail should be marketed without brightly colored cherries ... cherries are clearly identified by the consumer as the ingredient which makes fruit cocktail the most desired fruit dessert."