By Katherine Hobson From npr

Kids can be cruel, especially about weight. So you might think overweight or obese children know all too well that they’re heavy — thanks to playground politics. But that’s not necessarily so, according to government data covering about 6,100 kids and teens ages 8-15.

About 30 percent “misperceived” their weight status (underweight, normal weight, overweight or obese), according to a report from the Centers for Disease Control and Prevention’s National Center for Health Statistics. (The CDC bases those categories on body mass index, adjusted for gender and age.)

Among children and teens who were actually designated by the CDC as overweight — or between the 85th and 95th percentiles on the CDC’s growth chart — 76 percent thought they were “about right”; about 23 percent said they were overweight. Among obese kids and teens (those in the 95th percentile and higher on the chart), roughly 42 percent thought they were OK weightwise, while 57 percent thought they were in the “overweight” category. Boys, younger kids and children from poorer families were more likely to misperceive their status.

So is it a bad thing if a kid doesn’t know he’s overweight? The report notes that research has linked knowing your weight status to trying to change behaviors.

“Children who don’t have a correct perception of their weight don’t take steps to lose weight,” such as increasing physical activity or changing eating habits, Neda Sarafrazi, a nutritional epidemiologist with NCHS and an author of the report, tells Shots.

Other studies have suggested that parents are in the dark about their kids, too, with about half underestimating their obese or overweight child’s weight. Sarafrazi says it’s key for parents to know the truth.

Paris Wood, 14, has her measurements taken as part of a Chicago anti-obesity program.

But kids and teens already worry a lot about their weight, as an NPR parenting panel discussed recently.

Marlene Schwartz, a psychologist and director of the Rudd Center for Food Policy & Obesity at Yale University, tells Shots that while she’s a big proponent of keeping tabs on kids’ BMIs in the aggregate, she’s not sure it’s helpful to label kids as overweight. More helpful, she says, is giving kids feedback about their physical fitness and what they eat — noting ways to improve.

And if children are obese, or are having weight-related medical problems, Schwartz says, it’s better to encourage them to get healthier by cutting out snacking in front of the television or cutting out sugary drinks than to tell them they need to lose 20 pounds to be considered “just right.”

“Shame is a terrible motivator,” she says.

The disconnect occurred mostly — but not exclusively — among kids who were heavier than average. Of the children who were normal weight, most knew it, while less than 4 percent thought they were overweight and less than 9 percent thought they were too thin. About 49 percent of underweight kids thought they were about right; the rest knew they were too thin.

IMAGE: Fun hikes offer health benefits for kids of every shape and size.

Annette Birkenfeld/annedde/iStockphoto

For more on this story go to: http://www.npr.org/blogs/health/2014/07/23/334091461/many-kids-who-are-obese-and-overweight-dont-know-it