How does childhood obesity work?

Defining Obesity

The first step in going up against obesity is knowing what you're dealing with. At what point is a child considered overweight or obese? Can he or she be categorized as obese based on appearance alone? What about just the numbers on the scale? Once you know where you stand, you can determine where you are and where you want to go.

Medical providers use several factors to determine a child's starting point. The most significant measurement is BMI, which stands for body mass index. BMI takes into account a person's height and weight to measure body fat. But for children, assessing weight doesn't end with this number. A medical professional will take the result of the child's height and weight comparison and put that number up against kids of the same age. This is referred to as BMI-for-age. Girls are compared against other girls, and boys are compared against boys.

The result of that comparison is a percentile number showing how the child stacks up against his or her same-age counterparts. For example, if a 10-year-old girl falls within the 90th percentile, just 10 percent of other girls her age have a higher BMI than she does.

When it comes to whether a child is overweight or obese, the Centers for Disease Control and Prevention (CDC) have determined which percentile ratings put a child into these categories. A percentile ranking of 85th to 94th puts a child in the overweight category, while a percentile ranking of 95th and higher puts a child in the obese category [source: MayoClinic].

A child's BMI doesn't give the complete picture. Children aren't like a string of paper dolls, with each one the same as the last. Everyone is unique. Growth patterns vary. Children have different levels of muscle and varying frame sizes. And one child may have more contributing risk factors than another. These are all things that a doctor will consider before making a final determination and working with you to plan your child's success.

Speaking of risk factors, what are the things that would put your child more at risk of falling into the overweight or obese categories?