单选题
All 'that fault-finding about lowering cholesterol(胆固醇) and eating less fat must finally be paying off. According to a study published in the New England Journal of Medicine, more Americans are eating a healthy diet now than 30 years ago. In fact, according to researchers from the University of North Carolina, just about the only people who ate right in the mid-1900s were poor black people, who simply couldn't afford the steaks and high-protein meals that were then considered the most nutritious. According to survey data collected by the U. S. Department of Agriculture, more than 16% of poor black people in 1965 ate a healthy diet, compared with less than 5% of high-income whites. And what constitutes a healthy diet? Less than 30% of calories from fat. Five or more servings a day of fruits and vegetables. Six or more helpings of legumes (peas and beans) and cereals (谷类食物). Exactly the diet that rich health-conscious people started adopting in the U.S. in the 1980s. There's still a long way to go, however. Although both high- and low-income Americans have cut about 5% of the fat from their diet, they haven't replaced it with fruits, vegetables, grains and legumes. By 1991 only 20% to 22% of the general population was eating a healthy diet. Indeed, among poor blacks, the average number of servings of grains and legumes declined from six to five servings a day, and now equals the number consumed by whites. "The message about lowering fat has been heard", says Barry Popkin, a professor of nutrition at University of North Carolina who led the study, which was funded in part by the Kellogg Corp. "But we haven't been as loud and clear on fiber, sodium(钠), fruits and vegetables, grains and legumes./
单选题
______ people were the only people who ate right in the mid-1960s.