March 12 American children and teen-agers are heavier than ever and still gaining weight, according to a troubling report released Monday by researchers at the Centers for Disease Control and Prevention. 

A national survey showed that 13 percent of children

ages 6 to 11 were overweight in 1999, up from 11 percent in the previous survey, conducted from 1988 to 1994. The number of overweight 12- to 19-year-olds increased from 11 percent to 14 percent. 

"The number has not leveled off and it's still going up," said Robert Kuczmarski, a nutritionist at the CDC's National Center for Health Statistics, who helped conduct the study, known as the National Health and Nutrition Examination Survey (NHANES). The surveys have been conducted since 1963 and starting in 1999, NHANES became an ongoing study.

The prevalence of overweight kids was relatively stable from the 1960s to 1980, but in the past two decades the number has nearly doubled.

Susan Adams, a Seattle-area nutritionist with Washington State University and spokesperson for the American Dietetic Association, said there are many reasons for the increase.

"Even though we talk a lot about exercise, there are fewer physical education programs in schools," Adams said. "There's a trend towards super-sizing portions, a sense of unsafe neighborhoods [resulting in kids not playing outdoors as much as in the past], more time sitting in front of computers, video games and the TV ó and soda pop may be part of the issue."

The data on kids reflect a similar pattern among older generations: The latest NHANES report on adults found that the number of overweight adults jumped from 55 percent in the 1988-1994 survey to 61 percent in 1999.

"We are almost guaranteeing another generation of overweight adults," Kuczmarski said. "Kids who are overweight adolescents are almost destined to become overweight adults. Once you gain weight, as we all know, itís very difficult to lose it."

The trend is alarming not only for putting kids at risk of becoming overweight adults with chronic health problems, but also for the weight-related ailments increasingly popping up in children.

"We are seeing reports in the literature of some of the severely overweight children developing type 2 diabetes, what we used to call adult-onset diabetes, high blood pressure and high cholesterol levels," Kuczmarski said. 

The 1999 NHANES data come from measurements of 1,445 children. The survey defined overweight children as those with a Body Mass Index (BMI), a ratio of height to weight, above the 95 percentile for their gender and age. 

"These kids are very heavy," Kuczmarski said, noting the figures from the new report are probably conservative estimates of the number of overweight children in America. 

Researchers will further analyze the survey, breaking it down by race and gender, after the 2001 data is collected, Kuczmarski noted. 

One of the national health objectives for 2010 is to reduce the prevalence of overweight youths from the 1994 statistic of 11 percent. "Obviously some of  our prevention efforts are not working, Kuczmarski said. Adams emphasizes there should be more of a national commitment to promoting exercise and physical fitness.

"Parents should look for ways to have fun with the whole family in active ways," she said. "It's good for the health of both the kids and parents and their relationship."