Many kids today have their height and weight checked in school and are given BMI assessments, which are sent home. (BMI stands for "body mass index," which is calculated by measuring a child's weight and height.) But a quick scan of headlines about these assessments, which are sometimes referred to as "fat letters," shows that they're not always popular with parents.

Some parents have reportedly been upset by school BMI reports that reported their child's BMI as being too high, even though their child was not overweight and was physically active.

Other parents have criticized schools for sending these BMI reports home in a child's backpack, often without putting it in a sealed envelope, which means that young kids may be distressed by their own BMI assessments and classmates may be able to see and compare each other's results. Parents have also expressed concern that these reports could lead to kids developing anxiety and problems with their own body image.

Why Schools Measure BMI

There are many reasons why schools measure and report kids' obesity risk. Obesity in children has more than doubled in the last 30 years in the U.S., and among kids ages 6 to 11, the percentage of children who are obese increased from 7 percent in 1980 to almost 18 percent in 2012. Kids who are healthier miss less school, perform better academically, and do better on standardized tests, says Stephen Pont, MD, pediatrician at Dell Children's Medical Center in Austin. BMI reports can help raise parents' awareness about potential weight problems and help identify children who may need to be monitored by their pediatrician to keep them healthy and maintain a healthy weight.

On a larger scale, collecting data about students' BMI can provide valuable information that can benefit communities and can help get needed resources, such as increased funding for programs to promote kids' health.

"Screening tests are a way of saying, 'Hey, you should talk to your doctor,'" says Dr. Pont. "It's better to address a small problem early than to deal with it later." And there's little doubt that childhood obesity is a serious problem. Obese children are at increased risk for high cholesterol or high blood pressure and cardiovascular disease, are more likely to develop diabetes later in life, are at greater risk for joint problems and sleep apnea, and are more likely to be bullied.

Why Parents are Upset and Unhappy with School BMI Reports

While school BMI reports may be helpful, they are clearly touching a nerve, and in some cases, parents are protesting that the evaluations are not accurately reflecting how healthy their kids really are. And one of the biggest problems seems to stem from how the reports are sent to parents: Some schools are simply putting the report in folder for the students to put in their backpacks instead of mailing or emailing them to parents directly and protecting the privacy of the kids.

"Weight is a sensitive topic," says Dr. Pont. "As a society, we focus on individual choices." When someone is identified as having a high BMI, "people may incorrectly think you might be lazy, weak-willed." The fact is, we have a host of factors that are contributing to obesity, including the fact that we are on computers more, walk less, and drive instead of walk, says Dr. Pont. For kids, particularly those in lower socioeconomically-ranked neighborhoods, some factors that lead to increased obesity are unsafe parks or not having a grocery store that stocks healthy foods.

What Parents Can Do

The solution, says Dr. Pont, is not to do away with the BMI assessments but to make sure the data is obtained and shared sensitively. One way is to mail or email the results to parents rather than putting it in a child's backpack, similar to the way grades are sent. If your child's school is sending BMI results home with kids, talk to them about changing the way this information is shared. Other tips for parents to keep in mind:

• These reports are guidelines and reminders to have their child examined by a pediatrician and to practice healthy habits, like choosing healthy foods, making sure kids are active, and avoiding unhealthy choices like sugary drinks and spending too much time in front of a TV or computer screen.
   
• BMI reports for kids are different than those for adults. For one thing, the amount of body fat kids have can vary with age, and children experience growth spurts. There are also different body types--one child may naturally be lean while another may be bigger boned or more muscular in build. That's why annual checkups are important. A BMI report may not pick up a skinny child who may be unhealthy, for instance.
   
• School screening that are more comprehensive--measuring how fast kids can run a certain distance or how many push-ups they can do or how far they can stretch certain muscles--can give parents more information than simple BMI results.
   
• School BMI reports can be a perfect opportunity to talk about health, and what your whole family can do together as a family to stay healthy.
   
• Remember the 5-2-1-0 childhood obesity prevention guideline: 5 daily servings of fruits and vegetables, 2 or less hours of screen time, 1 hour or more of physical activity, and 0 servings of sugary drinks.
   
• Talk about health, good nutrition, exercise, and having fun while getting fit, and take the focus off physical appearance. Discuss media images that perpetuate stereotypes and help your child sort through messages that are harmful and unrealistic.
   
• If your child is upset about a BMI report, help her understand that it's only a general guideline and starting point to help all parents figure out whether or not they may need to make lifestyle choices to help kids be more healthy. It is by no means a complete and final picture of how healthy she is, and only her doctor and you and she can know exactly what she may or may not need to do for her to stay healthy and strong.