Keys’s work has long been regarded as classic, but even his devotees have hesitated to recommend that Americans start eating like Cretan peasants. Until now. Last month Walter Willett, chairman of the Nutrition Department at the Harvard School of Public Health, and Frank M. Sacks, a cardiovascular-disease researcher at Harvard Medical School, published an editorial in The New England Journal of Medicine in favor of “the traditional Mediterranean diet”–Complete with 35 to 40 percent of its calories from fat, chiefly olive oil. To most nutritionists, this is heresy. For years, the American Heart Association and other experts have been pleading with Americans to cut their fat intake from as much as 40 percent of calories down to 30 percent. Many nutritionists say even 30 percent is too high. Now we’re supposed to chug olive oil? “There’s more than one way to be healthy,” says Willett.
For Willett and Sacks, one of the most appealing aspects of the Mediterranean diet is its effect on HDL, the “good” cholesterol that actually seems to protect against cardiovascular disease. Low-fat diets tend to lower both good and “bad” cholesterol (LDL). The saturated fats found in beef, milk and butter are justly famed for their tendency to raise total cholesterol and clog arteries. But a diet rich in olive oil, which is monounsaturated, apparently helps keep the arteries clear and LDL levels low, while maintaining healthful levels of HDL.
Filling up on olive oil, while a delightful prospect to anyone sick of rice crackers, strikes many researchers as a risky policy. “I still believe total fats should be low,” says T. Colin Campbell, a nutritional biochemist at Cornell University, whose ongoing study of diet and health in China has revealed some of the world’s lowest rates of heart disease. The traditional Chinese diet, almost entirely vegetarian, gets about 15 percent of calories from fat–a level Campbell calls “the gold standard.” “I don’t see anybody being hurt by that,” he says. “Going to 35 or 40 percent is really asking for trouble.” But Willett and Sacks find such extremely low-fat diets impractical for Americans. “People won’t eat that way,” says Sacks. “They’re hungry all the time, and they won’t stay with it.”
Olive oil may be fine for the arteries, but the leading cause of death today among women under 65 is cancer. Willett notes that rates of breast and colon cancer in Greece are low, but other scientists call for caution. “The information we have on a range of cancers is very limited,” says Dr. Ross Prentice, director of the Public Health Sciences division of the Fred Hutchinson Cancer Research Center in Seattle. “There is no data to support an assumption that this recommendation won’t contribute to cancer. I would agree that it’s sensible to. switch to mono-unsaturates, but to go as far as 35 to 40 percent is very premature.”
Nutrition experts also question the wisdom of advising Americans to eat more fat, when our obesity problem is one of the worst in the world. Willett emphasizes that exercise, not fat intake, is the crucial factor in weight control. “If you compare a low-fat diet with a high-fat diet, there is not very much relation with obesity,” he says. “Our bodies are very efficient. If we cut down on fat, we seek more calories from other sources. But exercising regularly will cause people to lose weight, even though they may eat more.” The moral seems to be that if you plan to eat like a Cretan peasant, you’d better start living like one by slaving in the fields from dawn. “I think they’re being unrealistic,” says Bonnie Liebman, a nutritionist at the Center for Science in the Public Interest, a Washington , D.C.-based advocacy group. “Given our sedentary lifestyle, people may need a low-fat diet. Americans are not about to sell their cars.”
Even before the Willett-Sacks paper, olive oil had a big following in the nutrition community. It’s a good source of vitamin E, which may protect against both cancer and heart disease. But nobody can say whether the olive oil or something else in the traditional Mediterranean diet promoted long life. Philip James, Britain’s leading nutrition scientist and himself a proponent of the southern Italian diet, where olive oil provides about 20 to 25 percent of calories, says the oil so admired by Keys isn’t even produced anymore. “Those young men on Crete were not only exercising fiercely, they also lived on crude, thick green olive oil and vegetables,” he says. “No one is eating that crude oil now.” Like other experts, including Willett and Sacks for that matter, he puts much of his faith in fruits, vegetables and grains, which most of the world’s healthiest people eat in abundance. Olive oil may well become the oat bran of the ’90s, turning up in everything from potato chips to ice cream; if so, it’s a trend worth resisting. The right way to enjoy olive oil is with a perfectly ripe tomato, a chunk of crusty bread, and a friend. That’s Mediterranean. Taking Measure
Do Americans eat too much fat? Or not enough–of the right kind?
Calories From Fat AHA Recommendation 30% American Diet 35% Mediteranian Diet 32% SOURCE: AMERICAN HEART ASSOCIATION, NEW ENGLAND JOURNAL OF MEDICINE
