Helping Your Child Who is Overweight As a parent or other caregiver, you can do a lot to help your child reach and maintain a healthy weight . Staying active and consuming healthy foods and beverages are important for your child's well-being. You can take an active role in helping your child—and your whole family—learn habits that may improve health. How can I tell if my child is overweight? Being able to tell whether a child is overweight is not always easy. Children grow at different rates and at different times. Also, the amount of a child’s body fat changes with age and differs between girls and boys. One way to tell if your child is overweight is to calculate his or her body mass index (BMI). BMI is a measure of body weight relative to height. The BMI calculator uses a formula that produces a score often used to tell whether a person is underweight, a normal weight, overweight, or obese. The BMI of children is age- and sex-specific and known as the “BMI-for-age.” BMI-for-