In the late 1950s doctors studied the foods, especially the fatty meats, butter, eggs and milk consumed daily by 1,900 Chicago men aged 40 to 45.

By the time they were 60 to 65, it was reported today, those who ate a lot of fat and cholesterol had suffered over a third more fatal heart attacks than their lean-eating fellows.

The new report -- in today's New England Journal of Medicine -- strongly reinforces the view that a high-fat, high-cholesterol diet can clog arteries and cause heart disease.

The question is one of the most controversial in medicine.

Last February the Departments of Agriculture and Health, Education and Welfare reviewed all the evidence. Then they officially recommended that Americans should eat less fat -- especially less saturated or solidified (mainly meat and dairy) fat and less cholesterol -- to try to avoid premature death.

In May the Food and Nutrition Board of the National Academy of Sciences disagreed. Its members, several of them scientists with food industry ties, said the evidence for a lower-fat, lower-cholesterol diet for all Americans was not yet convincing though persons with a family history of heart disease might want to follow such a diet.

The American Heart Association, most heart specialists and officials of the government's National Heart, Lung and Blood Institute have clung to the view that a low-fat diet is a prudent, though unguaranteed, step toward longer life.

The Chicago study was conducted by scientists at Chicago's Rush-Presbyterian-St. Luke's Medical Center and three universities, Harvard, Michigan and Northwestern.

No single study can prove or disprove a diet-heart disease link, said the new report's seven authors, headed by Dr. Richard B. Shekelle. But the Chicago study, he said, is in line with "the weight of evidence" of the last decade.

In 1957 and again in 1958 the Chicago study group examined the eating patterns and other habits of middle-aged workers at a large Western Electric plant. The scientists classified the men into low, middle and high thirds, according to their fat and cholesterol intake.

Statistical tables in the new report show that by 1977 about 13.5 percent of the "high" saturated fat and cholesterol eaters had suffered fatal heart attacks, compared with about 9.5 percent of the "low" fat and cholesterol eaters. These figures are averages of two closely parallel "diet sources" used. By one, the high fat group had a 38 percent greater chance of fatal heart attack; by the other, a 44 percent greater chance.

Still the figures probably underestimate the real toll, and "I think the effect is even greater than our measurements show," Shekelle maintained.

Consumption of dietary cholesterol (found heavily in eggs yolks and shrimp but also in other fatty foods) had a greater effect in these men than saturated fat consumption. But based on a study of many populations, Shekelle said, "we advise" lower consumption of both saturated fats and cholesterol, with a "modest increase" in use of polyunsaturated fats (found in many oils and soft margarines).

In this study and others, the measurements all tend to be rough averages and somewhat uncertain, scientists say. The problem, they report, is that they must gather their information in a "real world" where it is hard to get facts on diets, and it would take a virtually lifelong and almost impossible kind of study of thousands of people to get a precise picture.