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.