A Food Lover's Guide To Fat

Good question. unfortunately, there's no single good answer. You certainly need some fat -- it's an essen-tial nutrient, just like protein and carbohydrate. But start talking about amounts, and the experts start arguing.

For years, researchers have been producing graphs showing high rates of cancer and heart disease in hamburger-and-milkshake countries like ours and low rates in Asian countries, where people eat mostly fish, grains and vegetables. Now that Japan is becoming a hamburger-and-milkshake country itself, chronic-disease rates are rising there, too. This was the data that encouraged the U.S. government to start beaming out the dietary advice, ""30 percent of calories or less from fat,'' back in 1977. It quickly became a mantra; today it's invoked by most of the medical establishment and enshrined on food labels. It means if you consume, for example, 1,800 calories a day -- the recommended amount for an active woman weighing about 130 pounds -- then 30 percent, or 540, of those calories can come from fat. That's about 60 grams of fat per day, or aboutas 14 teaspoons' worth. No more than 10 percent of the 60 grams should be saturated fat, the kind in meat and dairy products (and coconut oil). (If you must know, saturation refers to the molecular structure of the fat. All fats contain atoms of carbon and hydrogen; the more highly saturated the fat, the fewer spaces it has for extra hydrogen atoms. Highly saturated fats promote clogged arteries; monounsaturated and polyunsaturated fats do not.)

However: most experts freely admit that 30 percent won't offer much protection against cancer or heart disease. But they saw little hope of getting Americans to slash their fat intake from close to 40 percent, which it was at the time, to the Asian level of 20 percent or less. ""Many of us think of 30 percent as a practical, intermediate step,'' says Peter Greenwald, director of Cancer Prevention and Control at the National Cancer Institute. Most Americans could get down to 30 percent fairly easily by cutting way back on meat, junk food and fast food. Eliminate those sources of fat entirely, or save them for occasional treats, and you're closer to 20 to 25 percent, the level many experts choose for themselves.

Aren't some fats good for you? What about olive oil? And don't just say, "More research is needed.'

The saturated fats in meat, butter and whole milk have long been demonized, and for the most part rightly so. Recent research on heart disease and sever-al cancers -- including colon, prostate and ovary -- points to one overwhelming message: eating a lot of red meat is a really bad idea. The beef industry promotes a three-and-a-half-ounce serving of meat, about the size of a deck of cards, as perfectly healthful, which it would be if anybody actually ate a serving that small and indulged only occasionally.

Olive oil and canola oil, on the other hand, are getting the best press since oat bran. These monounsaturated oils were once carelessly lumped with their polyunsaturated siblings -- corn oil, sunflower, soy and the rest -- as an improvement over butter and lard, but still (ugh) fat. No more. While the polyunsaturates remain a better choice than butterfat, they're less effective than olive and canola oils at lowering blood levels of LDL, the ""bad'' cholesterol, while maintaining HDL, the ""good'' cholesterol. And some experts believe that generous amounts of olive oil help account for the low rates of heart disease traditionally enjoyed by people in Mediterranean countries. Then there are the wild cards, the fats that make shopping so irritating because the news on them keeps changing. Margarine, for instance: it was never a very pleasant butter substitute, but at least it seemed to be a prudent one. Now studies indicate that fats called trans-fatty acids, found in margarine as well as in other solid shortenings, may clog arteries just as efficiently as butter. And cheese: it used to be a high-fat dairy product, end of discussion. Now it appears that, unlike milk, cheese may not promote clogged arteries, at least among those happy laboratory animals in which the most convincing data has turned up. According to Serge Renaud, research director of INSERM, the French equivalent of the National Institutes of Health, one reason the inhabitants of Toulouse, France (big cheese-lovers), have only half the incidence of heart disease as their compatriots in Lille and Strasbourg (butter mavens) may be the difference in the dairy fats they consume. So far, alas, nobody but Renaud is as confident about these early findings as he is. Most American nutritionists approve of the fat-free cheeses now on the market; too bad they taste like rubber.