Six years after California instituted a statewide effort to pare fat and boost fitness in its schoolchildren, the kids haven't reversed the trend of growing obesity in their ranks. But they are fitter and, as a group, have slowed the growth of obesity, according to a new study.

The first comprehensive assessment of a pioneering statewide campaign to fight child obesity found that between 2003 and 2008, the rate of obesity among children in grades five, seven and nine grew by .33%. That may seem nothing to crow about, but it is a far slower rate of growth than has prevailed in recent decades, when obesity among children was growing by between .8% and 1.7% per year.

At the same time, California schoolchildren's fitness levels showed small but steady gains. Researchers at UC Davis reviewed the results of fifth-, seventh- and ninth-graders' Fitnessgrams -- assessments of each student's performance on tests measuring body composition, abdominal strength, trunk extensor strength, aerobic capacity, upper body strength and flexibility.

In all, 35.4% of California schoolchildren were overweight or obese in 2008 (17.44% overweight and 17.96% obese). That's up from 33.34% in 2003 (17.05% overweight and 16.29% obese).

While body composition (assessed by measuring skinfolds with calipers, by the standard body-mass index and by a handheld device called a bioelectric impedance analyzer) did drift upward in all grade groups, despite a decline in fatness among Asian and non-Latino white kids, and among girls in general. But while abdominal strength also suffered a small decline, every other area of fitness saw improvements in students' overall ratings. The number of kids who achieved a perfect fitness score -- meeting fitness standards in all six categories -- went from 28.98% in 2003 to 34.84% in 2008.

"The slowdown in obesity rates and the improvements in physical fitness might be an early sign of a turning point in childhood obesity," wrote the authors of the study, published in this month's American Heart Journal, a publication of the American Heart Assn.

The study is one of the latest to suggest a glimmer of hope that growing awareness and a raft of public policy changes is curbing the epidemic of obesity -- or at least preventing a new generation of Americans from carrying it forward.

The authors were particularly pumped about improvements in childrens' aerobic capacity, which they said strongly suggests that kids stepped up their levels of physical activity in the six-year period. That may be the result of burgeoning public health campaigns encouraging kids to exercise (including First Lady Michelle Obama's Let's Move campaign). But some credit, no doubt, is due to the state's requirements, starting in 2006, that all public schools provide, over each 10-day period, 200 minutes of physical education to all kids in grades K-to-five and 400 minutes to all kids in grades six-to-12.

"The best way to stop and eventually reduce childhood obesity has yet to be discovered," the authors wrote. But their study did identify several age and ethnic groups whose problematic patterns of consumption and sedentary behavior may need stronger medicine to change. Poorer fitness and body composition scores were consistently seen in counties with lower incomes and higher levels of unemployment. African Americans and Latinos had less lean body composition score than Asian and non-Latino white kids and lagged behind those groups in measures of abdominal strength and trunk extensor strength (basically, the ability to lift the upper torso off the floor).

And in this California sample, growth in obesity rates seemed to be greatest among younger kids between kindergarten and fifth grade. Despite improvements in school nutrition and fitness levels, children who were obese in the fifth grade tended to remain obese in subsequent years, said lead author Dr. William Bommer of UC Davis' School of Medicine. "And we suspect this trend begins before kindergarten," he added. 

That suggests that targeting kids as soon as they arrive at school might be the best way to drive down future obesity levels and build fitness. "We will need to consider new interventions for the K-through-five students," the authors declared.