New research indicates the problem of childhood obesity is much worse than health experts originally thought.

A new study by the Kaiser Permanente Southern California's Department of Research and Evaluation indicates that one child in five is obese. They also warn that extreme obesity is rising among people of all races and ages in the U.S.

Doctors say that without major lifestyle changes, kids today face a 10 to 20 year shorter life span.

"Children who are extremely obese may continue to be extremely obese as adults, and all the health problems associated with obesity are in these children's futures," study author Corinna Koebnick said in a Kaiser Permanente news release.

In addition, she warned such kids would "develop health problems in their 20s that we typically see in 40 to 60-year-olds."

The study, published in the Journal of Pediatrics, included 710,949 children between the ages of two to 19 years old.