How Does BMI Differ For Children?

Keith Ayoob answers the question: 'How Does BMI Differ For Children?'

ByABC News
December 22, 2008, 3:55 PM

February 1, 2009 -- Question: How does BMI differ for children?

Answer: Body mass index, or BMI, is a measure of weight compared to your height. And it's figured out the same way for adults and children, but for adults, the normal range of BMI is the same for all adults. With children, they grow at different rates, so it's a measure of weight for height for them, compared to other children their age. When you calculate their child's BMI and compare it for age, you create what's called a BMI or body mass index percentile.

A little example would be if your child's body mass index is at the 50th percentile, that means, that half the children his age or her age have a lower BMI, and half the children have a higher BMI. If your child is at the 85th percentile that means their BMI is higher than 85 percent of the children his or her age. And that's actually the lower limit of body mass index indicating that your child is at risk for overweight.

A child with a body mass index at the 95th percentile or above, is considered to be overweight. If your child is in this category be sure to check with your child's pediatrician as to the best strategies to go about changing it. It doesn't mean that weight loss is necessary. It may be that your child needs to take some efforts to stabilize weight until growth catches up.