BMI, Overweight and Obesity: What Parents Need to Know

Overweight and obesity—in adults and children—are causing a national health crisis. Currently, they’re responsible for more deaths in the United States each year than cancers, accidents and AIDS combined. In 2007, U.S. health authorities issued recommendations for health professionals to work with children and adults on preventing, assessing and treating overweight and obesity. The following is a summary of the recommendations for doctors to address overweight and obesity at children’s checkups, beginning at age 2.

Height, Weight and BMI
At least every year, a child should have her height and weight measured. In addition, the doctor should calculate the child’s Body Mass Index, or BMI. This is the best measure of her weight for her height, or how healthy her weight and body fat are for her size.

Checking a child’s BMI, in addition to weight, helps to identify a healthy weight, taking into account the natural ranges in children’s height at each age based on their family genetics and rate of development.

To calculate your child’s BMI, you can go to the Centers for Disease Control website (www.cdc.gov) and locate the BMI calculator for children and teens. Simply insert your child’s age, sex, height and weight.

Interpreting the BMI
Once you have calculated your child’s BMI, you and your doctor can plot the BMI number on the “BMI-for-age” growth curve for your child’s sex and age. There are slightly different standards for boys and girls, and different BMIs are healthy at different ages.

Plotting the BMI on the BMI-for-age chart will show what “percentile” the BMI is for your child’s age. This indicates your child’s weight status relative to the other children of the same sex and age.

For example, if your child’s BMI is at the 50th percentile for his age, that means that he is around average: heavier than 50 percent and lighter than 50 percent of the children his age and height. If your child’s BMI is at the 90th percentile, he is heavier than 90 percent of the children his age and height.

Based on your child’s BMI percentile, you can determine your child’s weight status: underweight, healthy weight, overweight, or obese, as described in the chart below:

Weight Status Category
Percentile Range
Underweight
Less than 5th percentile
Healthy weight
5th to 84th percentile
Overweight
85th to 94th percentile
Obese
95th percentile or greater


Following your child’s BMI over time
A one-time measure of your child’s BMI may not tell the whole story of her weight. For example, during puberty, children often have a rapid gain in weight and BMI, but the BMI may return to normal as the child grows and spreads out her weight over her taller frame. The doctor needs to follow your child’s BMI measurements over time to best determine whether she has a healthy growth in weight and height.

After BMI, then what?
In addition to weighing and measuring your child, and determining your child’s BMI percentile and weight status, your doctor will need to do a full physical exam and check his blood pressure. This is important because higher blood pressure and other physical complications can be seen with overweight and obesity in children.

In addition, your doctor will want to talk with you about your child’s and your family’s health practices. Be sure to discuss the following:

1. Is there any family history of obesity or medical conditions that might be related to overweight, such as Type II diabetes, high blood pressure, high cholesterol, heart disease and stroke?

2. How is your child’s nutrition?
  • How many meals and snacks does he eat? Does he eat breakfast?


  • Where does your child eat? How often do you have family dinners versus eating in front of the TV? How often do you eat at home versus out?


  • What kind of food does your child eat? How many fruits and vegetables does he eat versus sugary and fatty snacks? How much juice and soda does he drink?


  • What size portions does your child eat?

3. What is your child’s level of physical activity?
  • How often and for how long does he get moderate physical activity?


  • How much time does he spend every day in front of the TV or computer screen?

4. How do you feel about your child’s weight, and how does your child feel about her weight?
  • Do you feel that your child is a healthy weight or are you concerned?


  • Do you want to make any changes to help her achieve a healthier weight?


  • What might be some of the challenges and what might help in making healthy changes?

Depending on your child’s BMI, physical exam and other factors, the doctor might also order laboratory tests, such as blood tests for glucose and lipids.

Basic recommendations for children of all weights and BMIs

No matter what your child’s BMI and weight status, try to put into practice the following basic recommendations for healthy eating and physical activity:
  • Make sure your child eats breakfast every day.


  • Have regular family meals.


  • Serve your child at least five servings of fruits and vegetables daily.


  • Limit portion sizes.


  • Limit sugary beverages.


  • Limit eating out, especially fast food.


  • Encourage moderate to vigorous physical activity for at least 60 minutes daily.


  • Remove the television from your child’s room.


  • Limit screen time to no more than two hours per day.

For children with BMIs in the overweight or obese range
If your child’s BMI is in the overweight or obese range, be sure to work closely with your doctor and healthcare team to improve your child’s nutrition and physical activity to achieve a healthy weight over time.

Karen Sokal-Gutierrez M.D., M.P.H. Pediatrician