The U.S. diet has improved in recent years — but only some aspects of it and not among all demographic groups, according to a study published Tuesday in the Journal of the American Medical Association (JAMA).
Furthermore, the improvements that have occurred are relatively small.
Although most Americans are eating more whole grains and drinking less sugar-sweetened beverages than they were a decade ago, they are still consuming too few vegetables and too much processed meat and salty foods.
Given all the time, money and effort that have gone into public health efforts to persuade people to adopt a more healthful diet, the improvements described in this study seem, well, underwhelming.
For the study, researchers used dietary data collected from more than 34,000 U.S. adults aged 20 or older who participated in one of seven different National Health and Nutrition Examination Surveys taken between 1999 and 2012.
The participants’ diets were scored by how well they followed the dietary recommendations of the American Heart Association (AHA), especially in regard to the consumption of fruits and vegetables, whole grains, fish and shellfish, sugar-sweetened beverages, and sodium (salt). (For details about each of these recommendations, go to the AHA website.)
Using these scores, the researchers divided the survey’s participants into three dietary categories: “poor,” “intermediate,” and “ideal.” They later re-scored the diets to include three additional food categories mentioned in the AHA dietary recommendations — nuts, seeds and legumes; processed meat; and saturated fat.
An analysis of all this data revealed that the proportion of adults with poor-quality diets decreased from 55.9 percent to 45.6 percent during the period of the study, while the proportion with intermediate diets increased from 43.5 percent to 52.9 percent.
The proportion of people with ideal diets doubled, but from a tiny 0.7 percent to a slightly less tiny 1.5 percent.
Most of the dietary improvements came from eating more whole grains and drinking less sugary beverages.
The good news is that these two positive behavioral changes occurred in both genders and across all races, incomes and levels of education. Still, all the improvements noted in the study represent, at best, only a modest shift toward healthier eating habits. For, according to this study’s findings, almost half of American adults have dismal diets and only a very, very small percentage have ideal ones.
As background information in the study points out, a “suboptimal” diet is one of the leading causes of poor health in the United States, particularly obesity, diabetes, heart disease and diet-related cancers.
In fact, diet is estimated to be a factor in more than 650,000 deaths per year in the U.S., as well as 14 percent of all years lost to disability.
In the current study, both men and women showed an almost equal amount of movement away from a poor diet (from 58 percent to 49 percent among men and from 54 percent to 42 percent among women).
But the study found significant racial and ethnic disparities. The proportion of white adults with poor diets declined, but it remained essentially the same (statistically) for black and Hispanic adults.
Improvements were observed across all levels of achieved education, but people with the least amount of formal education were also consistently the least likely to have a healthy diet. In 2012, 58 percent of people with less than a high school degree had poor diets compared with 33 percent of those with a college degree.
Income level was similarly associated with the quality of the participants’ diets. Those in the study’s lowest income bracket were almost twice as likely to have a poor diet as those in the highest bracket.
Barriers to overcome
The study’s findings “highlight how barriers of race, low income, and poor education can reduce adherence to a healthy diet,” writes Dr. Margo Denke, an endocrinologist formerly with the University of Texas Southwestern Medical Center, in an accompanying editorial.
“Developing successful approaches to overcome these barriers will take cooperative efforts on the part of clinicians, policy makers, the food industry, and food distributors,” she adds.
FMI: Abstracts of the study and the commentary are available on JAMA’s website, but the full studies are, unfortunately, behind a paywall.