Some students are calling them "fat letters."
Schools in 19 states, including Arkansas, are sending home letters to parents indicating whether kids are passing the grade when it comes to Body Mass Index, or BMI.
But, are these tests backfiring?
"I'm insecure 'cause I'm taller than a lot of girls in my school. And I'm also bigger than a lot of them. I'm not incredibly skinny," said 13-year-old Lucy Williams.
Eating disorder experts worry the readings do more harm than good.
More than 40% of 9 and 10 year old girls have already been on a diet and as many as 60% of all 6 to 12 year olds are worried about their weight.
"I would like to see BMI testing in schools banned. for those who are already insecure about their weight-- these tests can potentially trigger an eating disorder," says one expert.
But pediatricians say right now BMI readings are the best tool doctors have to combat childhood obesity.