The diets of low-income Americans have worsened in the past decade, even as the diets of the wealthiest Americans have improved, according to a new study that is among the first to measure changes in diet quality over time by socioeconomic status. Overall diet quality in the United States remains poor, said the lead author of the study, published Monday in the Journal of the American Medical Association Internal Medicine.

Although the study found that the diet of all Americans improved on average between 2005 and 2010, the progress masked a decline in diet quality among the poor. The result: a doubling of the gap in diet quality between the wealthiest Americans and the poorest.

The study attributed the change to the