You may hear the term body mass index or “BMI” during your child’s checkups. It’s a tool doctors use to track a child’s weight in relation to their height starting at age two. Maintaining a healthy weight as kids grow and develop is important to their overall health and well-being.

While adults can be assigned numbers correlating to a BMI scale, for children a BMI is expressed as a percentile.

“We talk about the percentile, which is somewhere in that bell curve of normal,” says Pilar Bradshaw of Eugene Pediatric Associates. “We love to see a BMI percentile that is somewhere between the fifth percentile and the 84th. That’s what we consider to be a healthy range.”

Indication of proper nutrition
BMI is a measure of weight in relation to height. While it’s not a perfect measurement of body fat, BMI is a valuable tool in identifying children who are gaining weight too slowly or too quickly.

“If your kid is low on their BMI, it may be that they’re lacking in some nutrition,” Dr. Bradshaw says. “That’s worth a conversation with your child’s doctor and also if you have a very high BMI percentile.”

If your child has a high BMI, Dr. Bradshaw recommends focusing less on the number and more on creating healthy lifestyle habits. “There are some real positive ways that we can talk about just general health, like eating healthy foods, lots of fruits and veggies, drinking lots of water, moving together as a family.”

Tracking a child’s BMI is also important in relation to their family medical history, Dr. Bradshaw says. “So, if you have family members who have type-2 diabetes, who have high blood pressure or maybe have had strokes or heart attacks before the age of 50, those are important cardiac risk factors to talk to your pediatrician about, so we can start thinking about an overall health plan for your kid that’s not just about the BMI.”

Tips for healthy changes
There are steps you can take to encourage healthy lifestyle changes in children. Five ways to encourage healthy habits include:

  1. Be a healthy role model: Strive to be physically active as a family.
  2. Avoid buying junk food and limiting processed foods.
  3. Don’t use food as a reward: Instead, try a fun outing like a trip or a picnic.
  4. Have children help prepare meals and eat together as a family.
  5. Schedule annual well-check visits with a pediatrician.

It’s never too early to emphasize a healthy lifestyle, Dr. Bradshaw says. “If your child’s BMI percentile is high when they’re 2 years old, they’re much more likely to have a high BMI percentile when they’re 5, when they’re teenagers and really for a lifetime,” she says.

If you have questions or concerns about your child’s body mass index, talk with your doctor.