How does childhood obesity work?

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?

If you hopped into a time machine and made your way back to 1977, you'd think someone had shrunk all the snacks in the vending machines. That's because soft drinks went from an average 12.2 ounces to a whopping 19.9 ounces between 1977 and 1996, and salty snacks went from an average 1-ounce serving to 1.6-ounce serving [source: U.S. Department of Health & Human Services]. This increase in portion sizes leads us to our next topic: contributing risk factors for childhood obesity. Bad nutrition choices and lack of physical activity sit right at the top of that list. Let's examine these two and other risk factors more closely.

Poor diet is one risk factor for childhood obesity that we all know. Overeating causes a child to take in more calories than he or she needs to function, which leads to weight gain. The large (read: too big) portion sizes you find on restaurant plates don't help. Foods that are packed with sugar, fat and calories, such as candy, fast food and soft drinks, mean excess calories, too.

Not getting enough physical activity is another risk factor. Thanks to television, video games and recreational computer use, children are finding more reasons to settle into a comfy chair. They aren't moving around in physical education classes, either. In fact, as of 2003, just 28 percent of adolescents took part in daily physical education classes [source: Centers for Disease Control and Prevention].

In addition to diet and exercise, there are other significant risks that factor into a child's chances of being obese:

Combine any of these risk factors with a poor diet and sedentary lifestyle and you have a dangerous mix. Once a child has moved from risk to reality, there are health issues and life challenges that he or she is more likely to confront than children who aren't obese.

What if, on your third-grader's birthday, you cheered, "Happy 38th birthday, honey"? Seem like a stretch? According to Walt Larimore, M.D., an 8-year-old kid with high blood pressure (hypertension) is 38 when it comes to vascular health. He also says that 8-year-olds who have metabolic syndrome will find themselves with either heart disease or type 2 diabetes by the time they're 18 [source: Porter]. Metabolic syndrome is a combination of risk factors common to people who are overweight or obese. Some of these risk factors include a large waistline, high blood pressure and high blood sugar.

Other physical complications associated with obesity include:

These physical complications are unfortunate enough, but childhood obesity has also been linked to social and emotional challenges. For example, obese children are apt to have low self-esteem, deal with depression and exhibit learning and behavior issues. This could be a result of, or compounded by, social stigma and bullying associated with their weight.

Childhood obesity appears to correlate with negative social consequences well into adulthood. University of Michigan epidemiologist Philippa Clarke found through a study of 5,000 high school graduates that being overweight is negatively tied to traditional evaluations of success. By categorizing the graduates into weight classes -- overweight since graduation or overweight over time since graduation -- and then revisiting their lives at 40, Clarke found that those who were chronically overweight at 19 had a 50 percent better chance of being single, without a job and on public assistance [source: Neighmond].

If you're concerned about your child's health, there's no time like the present to start you and your child down the path to a healthy life. After all, if you reverse Clarke's study, that means that those people who were of normal weight at 19 had a 50 percent better chance of having a life partner and employment.

On the next page: your first to-do item.

When it comes to cutting childhood obesity off at the pass, your first step is not to point fingers. Obesity arises from a variety of factors. Self-blame is not only unproductive, but also unfounded [source: Healthy Children]. Once you've kicked the blame to the curb, you're ready to move forward in a strategic manner. It's time to visit your child's health care provider.

During the visit, your health care provider may perform blood sugar and cholesterol tests. He or she will also be looking for some background information from you. For example, be prepared to provide information about your family's medical history, your child's eating habits and activity levels and any medications your child already takes.

Don't think that the conversation is a one-sided chat, though. This is also your chance to ask questions. Consider asking your provider for access to education materials on childhood obesity, things you can do at home to help your child and what treatment options are available.

For young children under 7, future chances of growth might make the goal of those treatment options to maintain weight rather than losing it. Obese children older than 7 and adolescents will likely have slow weight-loss goals -- maybe 1 pound a week or even a month [source: Mayo Clinic].

To achieve these goals, lifestyle changes -- improved diet and increased physical activity -- will come into play. Although medications are available, they aren't commonly used for children and adolescents. In addition, surgical avenues are reserved for special circumstances -- adolescents who are extremely obese and previously unsuccessful in their weight-loss efforts. Throughout treatment, also keep in mind that fad diets and so-called quick fixes are dangerous for your child. Instead, together with your health care provider, you can move forward with safe, effective weight management tactics.

So what lifestyle changes, or healthy habits, are linked with getting the upper hand on your child's weight?

Turning a blind eye to a child's excess weight and planning to address it later means that he or she will face a battle with the scale well into adulthood. Overweight adolescents have a 70 percent chance of being an obese or overweight adult [source: U.S. Department of Health & Human Services].

The best time to try to turn things around is right now. And you can find motivation by taking a look at statistics from the other side. Take one study by the National Institutes of Health (NIH) and Harvard University. Researchers there showed that when overweight girls from a study group of 110,000 lost weight before growing up, they didn't just lose pounds -- they also lowered their chances of getting type 2 diabetes [source: National Institutes of Health].

The two best steps to take for getting to your goal are to improve your child's diet and increase physical activity. Your health care provider can give you detailed guidance, but below are a few diet and activity suggestions to get you started:

[source: Centers for Disease Control and Prevention]

Looking for other ideas on nutrition and physical activity? Check out the United States Department of Agriculture's Choosemyplate.gov and First Lady Michelle Obama's Let's Move! program.

Addressing your child's health now will lead to a lifetime of sound choices. But you'll also be helping everyone in the family, and together, you can achieve your goal of a healthier life.