The Aztecs didn''t cook with lard. The use of pig fat in Mexican cooking began only after the Spanish conquistadores introduced domesticated animals to Mexico in the early years of colonization. Lard, defined by the American Heritage Dictionary as "the white solid or semisolid rendered fat of a hog," was soon discovered to be an excellent medium for melding the aromatic spices of the New World, and holding the flavor of traditional dishes including the chocolate-based mole sauce, the corn masa used in tamales and the beans that formed the core of the early Mexican diet.

But while the use of lard survived independence, revolution and population explosions in Mexico, the low-fat health craze of the last 30 years is slowly spelling its demise in the U.S. And slurs like "lard-ass" and "porker," directed at the weight-challenged among us, point to a direct link in the American consciousness between pork fat and people fat.

In Mexican-food-rich Monterey County, many Mexican restaurants and taquerias are serving age-old traditional dishes with corn, peanut or canola oil instead of lard. "People ask us if we cook with lard, and when we say ''no,'' they all say ''that''s good,''" explains Juanita Fonseca of Mi Casita in Monterey.

Through the years and across the globe, lard has been hailed for its prodigal results in leavening, tenderizing, holding together layers of pastry, thickening sauces, and evenly carrying and holding flavor. From Indian fry bread, mid-Western fried chicken and Haitian beans and rice to Hungarian goulashes, Cajun biscuits and German short ribs, lard has played its hand.

Outside the kitchen, lard was a life-saver. Used for mechanical repairs and waterproofing through the years, lard assumed the central role of powering California''s lighthouses when the sperm whale population declined in the 1860s, tightening the market on whale oil.

The current backlash against lard boils down to cholesterol. Solid fats like lard are high in hydrogen-saturated fats, which raise the levels of dangerous cholesterol. Fatty cholesterol deposits in the arteries are linked to increased risk of heart disease, atherosclerosis and many forms of cancer. In health-conscious times like these, asserts Rudy Torres at El Palomar, "not cooking with lard gives people confidence in coming out to restaurants."

In the ongoing battle between "good" and "bad" fats, unsaturated fats are winning, at least in local Mexican restaurants. "We use peanut oil because it''s cleaner, lighter and absorbs less," says Scott Gonzalez, owner of Pacific Grove''s Peppers restaurant. Over the past 13 years of operation, Gonzalez says Peppers has received only one or two complaints about the absence of lard.

Zulma Valdez of La Villa Taqueria in Seaside, says many customers have received doctors'' orders to stay off lard, and the restaurant is pleased to comply. Valdez, who looks even younger than her 27 years, explains, "some customers come in sick and they can''t eat animal fat. Sometimes they ask for deep fried tacos but we don''t make those. We like to stay healthy here, we only use vegetable oil."

And they''re not the only ones. Papa Chano''s in Monterey and Sand City uses only corn oil, and many others, including Salinas oldies like Chapala Restaurant, Chiquita Taqueria and Carlito''s Restaurant, also avoid lard altogether. Several restaurateurs add that even in Mexico proper, the use of lard is declining as alternative oils and health information become more readily available. "It used to be that every Mexican meal started with a little scoop of lard in the pan," says Torres. "Now often it starts with oil."

But lard isn''t throwing in the towel yet. A countywide lard census would be useful in ascertaining the exact amount of animal fat used in Mexican restaurants, but it is clear that lard use is still alive in Monterey County restaurants. Baja Cantina and Grill''s Barbara Parker says the restaurant continues to cook with lard because of tradition and taste. "Using lard is the old way of cooking Mexican food and we are maintaining taste standards," she says. "We can say we are a little bit authentic and a little nouveau. I don''t think lard is a problem, people just need to get used to it."

Many cookbooks also continue to support the use of lard in limited doses, arguing that lard is less high in saturated fats than most other animal fats and is a good source of oleic acid. After all, we do rely on fat for essential fatty acids and fat-soluble vitamins. Lard supporters are finding voice through venues like the Cooking with Lard cookbook by Mike Smith et. al., and pro-lard Web sites like that of the British Lard Marketing Board. If you can''t find lard in your local market, just check out www.elard.com.

Some restaurants that have forgone lard agree that animal fat adds a flavor punch that other fats lack. "Cooking with lard is authentic and flavorful, but we don''t claim to be authentic--we are a Mexican-Latin American seafood grill with California influences," says Gonzalez of Peppers. "We cook with almost 100 percent fresh food, and flavor our dishes with lots of fresh herbs, lemon-lime juice, chiles and garlic."

Torres says that particular dishes, including tamales and beans, suffer the most from not using lard. El Palomar and La Villa Taqueria both experimented with new ways of cooking beans to enhance the flavor that lard typically provides. Laura Ruiz of Chapala Restaurant says that lard is not necessary for rich-tasting, authentic Mexican food, as the restaurant''s all-purpose vegetable shortening brings out the real flavors of handmade food and fresh, hardy seasonings.

In this country plagued by both extreme obesity and life-threatening eating disorders, of both emaciated celebrity idols and a propensity toward greasy fast food, new medical studies are quick to dispel earlier hype and trendy obsessions. Perhaps the best motto in the lard story is a familiar one: all things in moderation.