Screening for unhealthy weight in children and adults

Children (ages 2 to 19)

Doctors weigh children at routine checkups. They plot measurements on a growth chart to see how your child compares physically to other children of the same age. This chart is updated each year during the routine exam to document the child's growth pattern.

"Overweight" and "at risk of overweight" are terms sometimes used when referring to children who weigh more than expected. Doctors use the U.S. Centers for Disease Control and Prevention growth charts or the body mass index (BMI) to measure a child's weight in relation to his or her height. To find out your child's BMI, use this Interactive Tool: Is Your Child at a Healthy Weight?

If you have concerns that your child is overweight or at risk of becoming so, first ask your doctor to review your child's growth charts and medical history with you.

• If your child's BMI has been high on the growth chart from birth, this may be his or her healthy size and growth rate. He or she may simply be bigger than other children of the same gender and age.
• If your child's BMI pattern has suddenly jumped from a lower range to a higher range on the growth chart, your child may be at risk of becoming overweight. Your doctor will carefully track growth over time, watching for a change in the rate of weight gain.
• If your family has a history of obesity, your child has a higher risk of becoming overweight.

Sometimes a child's BMI and weight can increase without a child being at risk of having too much body fat. For instance, before and during puberty it is normal for children to have a significant gain in weight before they begin to grow in height. Also, children who are very muscular (such as children who are very active in sports), may have a high BMI but have normal or even lower-than-normal amounts of body fat.

If your child's BMI and growth pattern suggest a weight problem, your doctor will give your child an exam that looks for health problems that can cause weight gain. This may include questions about eating and physical activity habits. Regular checkups for health problems will also be important over time.

Adults (ages 20 and older)

The U.S. Preventive Services Task Force (USPSTF) recommends using BMI to find out which adults are at risk from being overweight and obese.¹

If you are age 20 or older, use the Interactive Tool: Weight and Health Risks to check your body mass index (BMI) when you know your height in feet and weight in pounds. Use the following BMI chart when you know your height in centimeters and weight in kilograms.

You can use a BMI measurement to decide whether your weight is dangerous to your health. If you have a BMI of 30 or higher, your extra weight is putting your health in danger. If you are Asian, your health may be at risk with a BMI of 27.5 or higher.²

Where you carry your body fat may be as important as how many extra pounds you have. People who carry too much fat around the middle, rather than around the hips, are more likely to have health problems. In women, a waist size of 35 in. (88 cm) or more raises the chance for disease. In men, a waist size of 40 in. (101 cm) or more raises the chance for disease.³ In Asian people, health problems are seen with a smaller waist size. In Asian women, a waist size of 32 in. (80 cm) or more raises the chance for disease. In Asian men, a waist size of 36 in. (90 cm) or more raises the chance for disease.²

For more information, see the topics Obesity, Healthy Weight, Healthy Eating, or Healthy Eating for Children.

Citations

1. U.S. Preventive Services Task Force (2003). Screening and interventions to prevent obesity in adults. Available online: http://www.ahrq.gov/clinic/uspstf/uspsobes.htm.

2. Purnell JQ (2005). Obesity. In DC Dale, DD Federman, eds., ACP Medicine, section 3, chap. 10. New York: WebMD.

3. National Heart, Lung, and Blood Institute, National Institutes of Health (2000). The Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults (NIH Publication No. 00-4084). Available online: http://www.nhlbi.nih.gov/guidelines/obesity/prctgd_c.pdf.