In recent years there has also been a slight drop in the fraction of daily calories that American adults get from fast food. But among some groups -- young black adults, people in low-income families -- fast-food consumption remains high and unchanged.
Those are among the findings of the federal government's periodic look at Americans' health, the National Health and Nutrition Examination Survey (NHANES). "I think there's some potential good news here," said Cynthia Ogden, who oversaw two studies released Thursday by the National Center for Health Statistics.
From 1999 through 2010, the average intake for boys age 2 to 19 declined to 2,100 from 2,260 calories per day. For girls, the decline was to 1,760 calories from 1,830 calories. Previously, daily caloric intake had been rising since the 1960s.
The percentage of calories from protein increased over the past 12 years, and the percentage of calories from fat did not change. What did change was the consumption of carbohydrates. It fell by 1 percent in boys and girls.
"The survey didn't look at sugar specifically. But other studies suggest that a decrease in carbohydrates is due to a decrease in added sugar," Ogden said.
From 2007 to 2010, adult Americans (defined as those age 20 and older) got 11 percent of their calories from fast food. That was down from 13 percent found in the previous NHANES survey, conducted from 2003 to 2006.
Blacks obtained 15 percent of their calories from fast food; for whites and Hispanics, the figure was 11 percent. The percentage declined slightly for whites over the two survey periods but didn't change for blacks or Hispanics.
Among people in their 20s and 30s, 15 percent of whites' and Hispanics' calories came from fast food. Blacks of that age group got 21 percent -- roughly one-fifth -- of their total calories from fast food. People age 60 or older got a much smaller portion of their calories -- 6 or 7 percent -- from that source.
Income level had little relation to fast-food consumption, except in the young adult (20-39) age group. Within that group, people in low-income households got slightly more of their calories from fast food than did people in middle-income families -- 17 percent vs. 14 percent. Obese adults also got more of their calories from fast food (13 percent) than adults of normal weight (10 percent).