Americas diet quality moved from an F to a D. Heres how to turn yours into an A – Boston News, Weather, Sports [Video]

(CNN) — There’s a crack of light shining through the dark clouds of America’s battle with poor nutrition and subsequent health issues, according to a new study that analyzed two decades of nutritional data.

“There is good news. Americans are starting to hear the message about nutrition, and some companies and restaurants are starting to make healthier products. It’s a little bit of an improvement,” said senior study author and cardiologist Dr. Dariush Mozaffarian, director of the Food is Medicine Institute at Tufts University in Boston.

However, he added, the majority of the improvement occurred between 1999 and 2010, with no advances in nutrition after that.

“We have stalled as a nation — and that does not bode well for our health,” Mozaffarian said. “If I was grading America on its diet, I’d give it a D—just up from an F.”

An upward trend, but more is needed

The number of adults in the United States who ate a poor diet …