Severe obesity on rise among U.S. children

These findings appear to be in contrast to a recent report that the prevalence of obesity among children two to five years of age decreased from 14 percent 2003-2004 to just over 8 percent in 2011- 2012.

Both studies used the National Health and Nutrition Examination Survey but the prior one examined only the last decade while the new study made use of all available years -- from 1999 to 2012, the researchers explained.

"In 2003, there was an unusual uptick in obesity among young children, which led to the appearance of a significant decline. However, when we look at the bigger picture, that change is not there," Skinner said.

She said one of the most important messages from their study " is whether we have an environment that allows for activity and encourages a healthy diet for all children, regardless of their weight."

Co-author Joseph Skelton of Wake Forest University Baptist Medical Center said the U.S. has made progress in public policy and healthy messages, but more must be done to help families lead healthier lives.

"The default in our country should not be unhealthy. We must support local changes in the environment, support each other as we try to live healthier lives, and support the health care changes occurring now that will make it easier for families to be healthy, " Skelton added. "We need to not only change the world, but change how we live in it."