The New York City Department of Education is sending "Fitnessgrams" home with 870,000 students, declaring where they fall on a scale from underweight to obese. Kids aren't supposed to look at the notes, which are based on BMI calculations from last November, but of course they're opening the letters and finding out the school district thinks they're fat.

"I was like, 'Oh, my God! Why did I get this?'" tiny third grader Gwendolyn Williams told the New York Post, "I'm 4-foot-1, and 66 pounds, and I'm like, what?!"

Gwendolyn, with a BMI of 19, falls in the 88th percentile for her age and sex, sho she's considered "overweight" according to the Centers For Disease Control's BMI calculator for children and teens.

Her mom found out about the Fitnessgram Wednesday night.

"She said, 'Hey, Mom. The school told me I'm overweight.' And then she started jiggling her thighs, and saying, 'Is this what they mean?'"

BMI is only a rough measure of overall health, and many experts consider it whack.

Even the CDC, which backs BMI as "a reliable indicator of body fatness," admits that it's "not a diagnostic tool."

For example, a child who is relatively heavy may have a high BMI for his or her age. To determine whether the child has excess fat, further assessment would be needed. Further assessment might include skinfold thickness measurements. To determine a counseling strategy, assessments of diet, health, and physical activity are needed.

The district says the aim of sending home notes based on potentially flawed BMI numbers is "just one indicator … which helps students develop personal goals for lifelong health."

But some experts are calling it fat shaming. The Binge Eating Disorder Association told the Post that "dieting, especially for kids, is the gateway drug for eating disorders, and so is the public shaming that can come with this."

The principal of Gwendolyn's public school told her mom the kids weren't supposed to open the Fitnessgrams, which doesn't actually address the problems with sending them home in the first place.

But you just can't trust kids these days. They're a bunch of overweight troublemakers.

[H/T NYPost, Photos via, Shutterstock]