BMI vs. Weight
This bathroom scale measures weight. Weight is often used as an indicator of health status, because people who are overweight may have too much body fat.
Why It Matters
- A better indicator of body fatness is the body mass index, or BMI. BMI is based on both weight and height.
- Use the body mass index calculator for children and teens at the following link: http://apps.nccd.cdc.gov/dnpabmi/. Find the BMI of real or made-up people. Be sure to view where they fall on the BMI percentile growth chart.
Show What You Know
At the link below, learn more about BMI. Then answer the questions that follow.
- What is weight? How is it related to mass? Why can weight be used as a measure of body mass?
- Assume that a girl who is exactly 12 years old has a weight of 100 pounds and a height of 5 feet 2 inches. What is her BMI?
- Find the BMI for the girl in question 2 on the BMI percentile growth chart. How does her BMI compare with other girls her age?
- How are BMI percentiles used to classify children in weight status categories, such as underweight and overweight?
- BMI is used to screen children for obesity but not to diagnose obesity. Explain why.
- Why must age and sex be considered when interpreting a child’s BMI?
- Assume that two children have the same BMI. One child’s weight is classified as healthy, but the other child’s weight is classified as overweight. Explain how this could happen. Include an example to illustrate your answer.
- Why can’t children’s body fatness be assessed using weight percentiles rather than BMI percentiles as long as age and sex are taken into account?