Although the American diet improved during the last three decades, fewer than 25 percent of people surveyed eat a healthful one, a new study has found.
The study, the first to compare national dietary trends over a long period in different economic groups of blacks and whites alike, also found that the diet of wealthier whites had improved most dramatically.
The research looked at four groups: wealthier whites and blacks, and poorer whites and blacks.
In 1965, wealthier whites scored lowest in the percentage eating a healthful diet, and poorer blacks scored highest, a discrepancy the researchers attributed to the difference in ability to afford substantial amounts of meat and other foods high in saturated fat.
By 1991, a higher percentage of Americans in general were eating health-promoting diets, having significantly reduced their consumption of saturated fats and cholesterol, and lowered their total fat intake to 35 percent of daily calories, from 40 percent.
The study found dietary change in both good and bad directions among all groups. While many Americans had switched from whole milk to low-fat or skim milk over the years, by 1991 they were also eating far more pizza, tacos and pasta dishes loaded with hidden fats.
Consumption of grains, fruits and vegetables - aside from fat-laden french fries - actually decreased among some groups. And the advice to eat more fiber seems to have fallen on deaf ears.
As a result of these trends, the differences in dietary quality between whites and blacks narrowed considerably after the mid-1960s, even though both groups were improving, the researchers concluded.
The study, which was financed in part by Kellogg Co., the cereal-making giant, was based on three similar surveys conducted by the U.S. Department of Agriculture, in 1965, 1977-78 and 1989-91, among a combined total of 32,406 adults.
In each of the surveys, thousands of people selected to represent the entire population were asked what they had eaten the day before. The researchers evaluated the findings of each survey in the context of eight dietary goals summarizing recommendations to reduce chronic disease that were formulated in 1989 by the National Academy of Sciences. The eight goals are these:
Reduce fat intake to 30 percent of total calories or less.
Limit saturated fat intake to less than 10 percent of calories.
Consume less than 300 milligrams of cholesterol a day.
Eat five or more servings of vegetables and fruits a day.
Increase consumption of starches and other complex carbohydrates by eating six or more servings of breads, cereals and legumes a day.
Eat moderate amounts of protein - less than twice the recommended daily allowance, or RDA.
Limit total daily sodium intake to 2,400 milligrams or less.
Consume the RDA for calcium.