Fifteen percent of obese children and teens are suffering from Fatty Liver Disease (Non-Alcoholic Steatohepatitis), say researchers. Fatty Liver Disease, in which fat accumulates in the liver, can cause scarring of the liver, sometimes requiring transplantation by adulthood.

"We are seeing a growing number of young people with Fatty Liver Disease, and we need to tackle the disease before it becomes full blown in adulthood," says Jean Molleston, who is a professor at Indiana University School of Medicine.

"We routinely test children for conditions with much lower incidence such as scoliosis. Although we do not yet have formal guidelines for screening for Fatty Liver Disease, I personally think that all obese children should be screened for Fatty Liver Disease so we can intervene before it damages the liver," Molleston said in a statement.

According to the American Liver Foundation, 10 to 20 percent of Americans have Fatty Liver Disease.