Some researchers are puzzled by the latest survey showing a drop in the percentage of calories from fast food.
The study from the Centers for Disease Control and Prevention finds that on an average day, U.S. adults get roughly 11 percent of their calories from fast food, down slightly from the 13 percent reported the last time. The survey covers the years 2007 through 2010.
The study finds that young adults eat more fast food than their elders and that blacks get more of their calories from fast-food than whites or Hispanics.
The authors couldn't explain the drop and at least one nutrition professor casts doubt on the latest results, saying 11 percent seemed implausibly low. He suggests some people might have underreported their consumption.
The study didn't include the total number of fast-food calories, just the percentage.