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Diet ‘report card’: Americans are still eating too many low-quality carbs

Americans are still consuming too many low-quality carbohydrates and more saturated fat than recommended, according to a new study from Harvard and Tufts.

The study, published in the journal JAMA, found that carbs from refined grains, starchy vegetables, and added sugars accounted for 42 percent of the typical American’s daily calories, researchers said. Only 9 percent of carbs were high-quality, from whole grains and whole fruits.

“Because low-quality carbs are associated with disease risk, taking in higher-quality carbs could mean better health for Americans in the future,” Zhilei Shan, nutritional epidemiology fellow at the Harvard T.H. Chan School of Public Health, first author of the study, said in a statement. At the time of the study, he was also working under the auspices of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.


Experts recommend that 45 to 65 percent of a person’s diet should be carbohydrates, but say people should limit carbohydrates from added sugars and refined grain.

The study looked at dietary trends over an 18-year period, examining data for 43,996 adults.

Total saturated fat intake was 12 percent of daily calories, above the recommended daily amount of 10 percent.

Over the study period, total carbohydrate intake and low-quality carbohydrate intake did go down slightly, researchers said.

The authors noted that dietary improvements were less pronounced, however, for people with lower income or lower education levels.

“Although there are some encouraging signs that the American diet improved slightly over time, we are still a long way from getting an ‘A’ on this report card. Our study tells us where we need to improve for the future,” co-senior author Fang Fang Zhang, nutrition epidemiologist at the Friedman School of Nutrition Science and Policy at Tufts University, said in the statement.

“These findings also highlight the need for interventions to reduce socioeconomic differences in diet quality, so that all Americans can experience the health benefits of an improved diet,” Zhang said.


The study was based on in-person health surveys conducted every two years that asked adults to recall what foods they ate in the previous 24 hours. Starting in 2003, adults were asked that question twice several days apart.

US dietary guidelines recommend a ‘‘healthy eating pattern’’ to reduce chances of developing chronic disease. The focus should be on nutrient-dense foods including vegetables, fruits, whole grains, low-fat dairy products; plus varied proteins sources including seafood, lean meats, and poultry, eggs, nuts and seeds, the recommendations say.

During the study years, US diabetes rates almost doubled, to more than 7 percent; obesity rates increased during many of those years, with about 70 percent of US adults now overweight or obese. Heart disease remains the leading cause of death.

Besides continued public health efforts, ‘‘Cooperation from the food industry’’ is key, a journal editorial said, including by reducing sugar, salt and saturated fats in foods.

Material from The Associated Press was used in this report.