Study Questions Impact Of NYC Students' Weight Report Cards

NEW YORK (CBSNewYork) -- The New York City school system is one of many nationwide that gives students report cards on their weight.

But a new study by the National Academy of Sciences found the policy doesn't spur weight loss.

The report cards list the child's body mass index (BMI) along with a designation ranging from underweight to obese. The city has been sending students home with these report cards for almost a decade in an effort to fight obesity and encourage children to be healthy.

Syracuse University professor Amy Ellen Schwartz and her team studied four year's worth of data and found those labeled "overweight" or "obese" generally did not go on to lose weight.

In fact, some students -- especially girls -- gained weight, WCBS 880's Alex Silverman reported.

"At first I was surprised because I really thought this was going to be helpful," Schwartz said.

She believes one issue might be the timing. The reports get sent home with the students -- instead of being mailed directly to the parents -- months after the children are weighed and in backpacks, not in the mail.

"It's possible the parents just didn't get them," Schwartz said. "If you can get it quickly I think that's going to make the difference and it's less about the wording."

The city notes it has changed the word since the four-year period the study focused on.

Now, instead of overweight and obese, the report cards say "needs improvement."

"They're moving in the right direction," Schwartz said.

At least 19 states now have instituted the report cards.