The nuggets came from two national fast food chains in Jackson. The three researchers selected one nugget from each box, preserved, dissected and stained the nuggets, then looked at them under a microscope.
The first nugget was about half muscle, with the rest a mix of fat, blood vessels and nerves. Close inspection revealed cells that line the skin and internal organs of the bird, the authors write in the American Journal of Medicine.
The second nugget was only 40 percent muscle, and the remainder was fat, cartilage and pieces of bone.
"We all know white chicken meat to be one of the best sources of lean protein available and encourage our patients to eat it," lead author Dr. Richard D. deShazo of the University of Mississippi Medical Center in Jackson, said.
"What has happened is that some companies have chosen to use an artificial mixture of chicken parts rather than low-fat chicken white meat, batter it up and fry it and still call it chicken," deShazo told Reuters Health.
"It is really a chicken by-product high in calories, salt, sugar and fat that is a very unhealthy choice. Even worse, it tastes great and kids love it and it is marketed to them."
The nuggets he examined would be okay to eat occasionally, but he worries that since they are cheap, convenient and taste good, kids eat them often. His own grandchildren "beg" for chicken nuggets all the time, and he compromises by making them at home by pan-frying chicken breasts with a small amount of oil, deShazo said.
Image: Chicken nuggets, via Shutterstock