ANN ARBOR—Why do the French, who turn up their noses at low fat diets, have lower than expected rates of heart disease than Americans? The key to what nutritionists call the “French Paradox” may lie in the impressive and widespread diversity of the French diet, according to a study from the University of Michigan School of Public Health and the Institut Scientifique et Technique de l’Alimentation in Paris. The study, which appears in the June 28 issue of the Journal of the American Dietetic Association, analyzes data from a dietary survey of 837 French adults (361 men and 476 women) in the Val-de-Marne department southeast of Paris. The data were collected in 1988-89. The survey recorded typical daily food intakes representative of a habitual diet over a period of at least six months.

“In general, the French ate more saturated fat than is recommended in U.S. guidelines. However, nearly 90 percent also reported eating a highly varied diet that consistently incorporated all of the five food groups?meats and fish, grains, fruits, vegetables, and dairy products,” according to Adam Drewnowski, director of the U-M Human Nutrition Program and principal investigator on the study. Few American surveys of diet intake patterns have focused on dietary variety, but the available data based on a single 24-hour recall found that only 33 percent of Americans consumed food from all five main food groups on any given day.

The French survey identified 73 separate foods and food groups: 10 kinds of meats and fish; 15 milk and cheese products; six fats and oil products; 10 grains (breads, cereals and pastas); 15 fruits and vegetables; eight sweets and sugars; five alcoholic beverages; and four non-alcoholic beverages including water and mineral water. The researchers evaluated the quality of the French diet according to two different standards. (1) A Diet Quality Index that indicates the degree of compliance with dietary guidelines established by the U.S.D.A. (United States Department of Agriculture), and (2) a five-point Dietary Diversity scale, which measures the consumption of foods in the five main food groups.

Generally, dietary guidelines recommend that people consume a diet containing: less than 30 percent calories from fat; less than 10 percent calories from saturated fat; less than 300 milligrams of cholesterol per day; less than 10 percent calories from sugar; and more than 50 percent calories from carbohydrates. Most of the French did not come close to meeting the U.S. guidelines. “Indeed, 63 percent of the participants scored just zero or one point out of five on the Diet Quality Index,” Drewnowski said. Eighty-four percent of the participants derived more than 30 percent of their calories from fat and 96 percent derived more than 10 percent of their calories from saturated fat.

“These figures for fat consumption are comparable to those reported in a U.S. studies of high risk populations with ‘a poor diet,'” Drewnowski commented. “However, the fat content of a diet reflects only one aspect of eating behavior. Our findings suggest that dietary variety? that is, maximizing the number of different foods from all of the five food groups?may have an even greater influence on good health than we have suspected.”

University of Michigan