Childhood Obesity and Body Mass Index (BMI)

How is childhood weight and obesity measured?

Body mass index (BMI) is a measure used to determine if a child is overweight or obese. It is calculated using a child’s weight and height. BMI does not measure actual body fat, but it is a good measure of body fatness for most children and teens.

To decide if a child is healthy or overweight an age-and sex-percentile is used instead a number. Children's body makeup varies as they age and also varies between boys and girls. The child is compared to other children of the same age and sex because their bodies are changing. For example, an 8-year-old girl with a 75-percentile BMI has a higher BMI than 75 out of 100 8-year-old girls.

BMI percentiles have weight groups:

• Underweight is below 5 percentile.
• Healthy weight is 5 to 85 percentile.
• Overweight is 85 to 95 percentile.
• Obese is 95 or higher percentile.

What are the consequences of childhood obesity?

Obese children are more likely to have:

• High blood pressure and high cholesterol, which puts them a risk for heart problems.
• Difficulty with their blood sugar.
• Breathing problems, like asthma.
• Muscle and joint problems or pains.
• Heartburn.
• Gallbladder problems.
• Risk of feeling bad about themselves and or having little confidence.

Plus, obese children are more likely to become obese adults.

Use a child and teen BMI calculator

Adapted from the Center for Disease Control and Prevention and in the public domain