Your Body Mass Index takes your weight and height and converts it to a score to tell you if you are at a healthy weight, underweight, overweight or obese. If you are overweight or obese, you could be at increased risk for several chronic diseases including cardiovascular disease, diabetes, arthritis and some forms of cancer. It is important to monitor this number if you are overweight or obese and work with your physician to lower your BMI.
According to the National Institute of Health’s Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults, adults who have a BMI of 25 or more are considered at risk for premature death and disability as a consequence of overweight and obesity. These health risks increase even more as the severity of an individual’s obesity increases.
“BMI is used for screening and research purposes. Many people become upset when told they are overweight or obese,” reports Eric South D.O. “It is helpful to remember this does not take into account your body composition but is a strictly a measurement just like your blood pressure. We use this to open communication about ways to improve your lifestyle and prevent problems in the future.”
The NIH has set these standards for BMI. A BMI of 25 to 29 means you’re overweight; a BMI of 30 or more indicates obesity. But Body Mass Index as a measurement tool isn’t right for everyone. The measurement is based on your height and weight. It is an indirect measurement of fat, so it doesn’t differentiate pounds of fat from pounds of muscle and bone. That being said, it can still be helpful in determining if steps need to be taken to create a healthier lifestyle and reduce the risk of being diagnosed with a chronic disease.
BMI for Kids
As children grow and their bodies change, it can be difficult for parents to determine if their child is in a healthy weight range. Your child’s BMI can also help you determine if he is at risk for health problems based on his weight.
The CDC and the American Academy of Pediatrics recommend BMI screenings for all kids age 2 and older. Here’s what you need to know about checking on your child’s BMI and what to do with the info once you have it.
“Calculating a child’s BMI number starts out just like calculating an adult’s BMI. The measurements are based on height and weight,” says Dr. South. “But for kids, height and weight alone aren’t as accurate as they are for adults. This is because kids’ body fat percentages adjust as they grow. Kids’ BMIs can vary based on their age and gender.”
That’s why when healthcare providers talk about a child’s BMI; you usually hear a BMI percentile, like 75th. These BMI percentiles show how a child’s BMI compares to other children of the same age and gender. To calculate the BMI percentile — which is also called “BMI for age” — a healthcare provider will take a child’s BMI, age and gender and compare it on a pediatric growth curve. This gives the child’s BMI percentile.
BMI percentiles are grouped into weight categories:
Underweight: below the 5th percentile
Healthy Weight: 5th percentile up to the 85th percentile
Overweight: 85th percentile up to the 95th percentile
Obese: 95th percentile or higher