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Childhood Obesity: Prevalence, Treatment and Prevention

by Doyeon Kim, MS and Len Kravitz, PhD on Jan 01, 2007

Become an advocate for kids by taking a leadership role in the war on obesity.

Fitness professionals know that the number of overweight or obese children in the United States and other developed countries is increasing at an alarming rate. However, it is difficult to track the prevalence of this obesity epidemic, since there is such variability in how experts define which children are overweight or obese.
Additionally, while we know that physical activity patterns and diet are contributing factors to this increase in overweight youth, our understanding of all contributing factors is presently incomplete. This article will examine the known negative consequences of childhood obesity and the recommended prevention and treatment options that fitness professionals can employ when dealing with youth.
Measuring Childhood Obesity
When it comes to research and epidemiological purposes, body mass index (BMI, calculated as body weight in kilograms divided by the square of height in meters [kg/m2]) serves as the relevant reference standard for determining the obesity and overweight status of children. Using this terminology, being “overweight” (often called “pre-obesity”) is defined as having a BMI of 25–29.9 kg/m2, whereas being “obese” means having a BMI of ≥30.0 kg/m2 (Janssen et al. 2005).
In a comparison of pre-obese and obese youth (ages 10–16) from 34 countries, the highest levels of overweight or obesity were seen in Malta, an island country located south of Italy in the Mediterranean Sea. The percentage of youth in Malta who were pre-obese was 25.4%, while the rate of obesity among youth was 7.9% (Janssen et al. 2005). The United States had the dubious distinction of placing second for the number of overweight or obese kids, with 25.1% of youth considered pre-obese and 6.8% deemed to be obese (Janssen et al. 2005). Among children aged 6–19 years, the most recent National Health and Nutrition Exam­ination Survey (NHANES)—using data collected from 1999 to 2002—found that the prevalence of overweight among American kids was three times greater than the goals established as part of the Healthy People 2010 campaign (Hedley et al. 2004).
Consequences of Childhood Obesity
Regardless of whether a child is considered pre-obese or obese, carrying excess weight during childhood can have serious consequences over a lifetime. These consequences involve negative effects on health, such as abnormal blood lipid levels and chronic inflammation, shown to contribute to heart disease and other serious health conditions later in life. For a look at the range of diseases obese kids face, see “Health Conditions Associated With Childhood Obesity” sidebar.
Another aspect of childhood obesity that often gets overlooked is the way it negatively affects kids from a psychological perspective. Being labeled as “the fat kid” in school can severely hamper a child’s self-esteem and self-image at a time when personality and confidence levels are being formed for life. We all know people who were overweight as kids and continue to suffer psychological scars, even if they have managed to shed pounds along the way to adulthood. Being overweight or obese as a child can lead to self-destructive behavior patterns that are hard to break and that may include high-risk activities that contribute to further unhappiness. See “The Psychological Effects of Childhood Obesity” sidebar for more details.
Causes of Childhood Obesity
Although there is still a lot to learn about the causes of childhood obesity, some things are clear. Experts theorize that kids are gaining more weight than previous generations for the following reasons:
• Physical activity is significantly down in schools nationwide.
• Kids spend more time in sedentary activities, such as working on home computers, watching TV and playing video games.
• Environmental factors, such as lack of safe playgrounds, have resulted in less physical activity among today’s youth.
Let’s look at each of these reasons in more detail.
Lack of Physical Activity
One factor that experts theorize has contributed to the rapid climb in childhood obesity is the change in physical activity levels and behaviors of children. The number of middle schools and high schools that offer formal or regular physical education (PE) programs has greatly decreased over the past few decades. More and more schools in America have either cut out PE entirely or are no longer providing as many hours of physical activities as they did in the past.
On the home front, today’s kids no longer play the way they used to play. In fact, some experts argue that the current emphasis on increasing exercise and physical activity is less important when reaching out to overweight kids than just encouraging them to play more often and more intensely (Burdette & Whitaker 2005). These same researchers say that unstructured outdoor play has the potential to improve all aspects of a child’s well-being: emotional, social, cognitive and physical (Burdette & Whitaker 2005).
In addition, the parents of many overweight kids often associate exercise and physical activity in general with their own failed attempts at weight loss—even if those parents have positive associations from having played as children themselves. Indeed, research conducted by Janssen and colleagues (2005) indicates that the best way to get kids moving is to take a multipronged approach, such as mixing informal play time with more structured physical activities at school.
The Media’s Role
Researchers have also come to recognize the role that sedentary behaviors, such as television watching and use of other media, contribute to the childhood obesity epidemic. Other media use is typically described as use of video games, computers, and audio devices such as CD and MP3 players.
As early as 1985, researchers reported on the direct relationship between television viewing (measured by time spent watching) and childhood obesity (Dietz & Gortmaker 1985). In the past two decades, many more media devices have become integral to the lives of children. In 29 out of 33 countries studied, Janssen and colleagues (2005) noted a strong association between increased use of different media and the rise in childhood obesity, along with a corresponding decrease in physical activity.
Other researchers have shown that television watching is also highly associated with increased rates of consumption of calorie-dense foods (Ebbeling, Pawlak & Ludwig 2002). The study found that children in the U.S. were spending 75% of their waking hours being inactive and were logging in only about 12 minutes of vigorous activity per day.
Other Environmental Factors
Changes in the environment over the years may also have played a role in the ways that kids move compared with years past, say some experts. Examples of environmental factors that may affect children’s physical activity levels include
• the rising cost of participating in structured activities, such as sports;
• lack of time on the parents’ part to facilitate interest in exercise among their children; and
• safety concerns, such as dangerous streets and playground availability (Ebbeling, Pawlak & Ludwig 2002).
What You Can Do to Prevent & Reduce Childhood Obesity
Physical activity and play are important components for the prevention and treatment of childhood obesity. Most American guidelines encourage youth—both normal-weight and obese—to get 30–60 minutes of physical activity (that produces a sweat) on most or all days of the week.
Compare these guidelines to those recommended by other countries: Great Britain urges its citizens to get 60 minutes of daily physical activity at least 5 days per week, whereas Canadian officials recommend that all adolescents gradually increase their physical activity participation to 90 minutes daily (Janssen et al. 2005).
Regardless of the length of time kids spend exercising each day, most experts agree that it is important that all physical activities be specifically designed or tailored for the particular child or group of children. For instance, creating a 12,000-steps-per-day incentive program for boys and girls will require a markedly different strategy for urban youth than it will for suburban kids, if only in having to account for environmental concerns, like access to safe streets or parks.
When it comes to teaching kids about the best foods for their growing bodies or instilling healthy behaviors for a lifetime, experts also concur on an approach to take. Parents, educators and fitness professionals should focus on teaching children about the benefits of a varied diet composed mostly of whole foods. In addition, kids need to learn about proper portion size and what constitutes a well-balanced diet. From a practical perspective, they should be taught which snacks are healthiest (read: fruits and veggies) and which contain too many calories.
Because of their strong association with childhood obesity, television viewing and use of other media devices should be limited. This may be one of our biggest hurdles, since advancing technologies are so much a part of children’s lives in the 21st century. One way to meet this challenge is to recognize the power of giving children accurate, honest and relevant education so they can succeed in life. As today’s young people begin to truly realize and appreciate the health consequences of childhood obesity, they just may be motivated to balance their lives with more play and physical activity.
As citizens of this country, we must also be advocates for creating safe environments in our communities where kids can play. Use your voting power to protect open spaces for kids’ recreational use and to encourage the development of better bike paths and parks and safer playgrounds for all people. Last, since obesity is a serious concern for adults as well as children, perhaps now more than ever is the time to initiate activities at your fitness facility that provide the “family unit” with opportunities for play and other ways to share physical activity.
Here’s to Kids’ Play
As conscientious fitness professionals and personal trainers, we can and should play a leadership role in helping to deliver health-promoting activities and programs that will stem the tide of the childhood obesity epidemic. Individually we can have a positive impact on this critical public-health problem by working with schools, fitness clubs, training studios, hospitals, public-health centers and city and state governments. Together we can take a leading role in effecting change at the local and national levels and ultimately bring about a resurgence of kids’ play and physical activity.
Doyeon Kim, MS, is a doctoral student in the exercise science program at the University of New Mexico, Albuquerque (UNMA). He earned his master’s degree in exercise and sport science in 2005 at the University of Utah. His research expertise is in childhood obesity, body composition, sports training adaptation and exercise prescription.
Len Kravitz, PhD, is the program coordinator of exercise science and a researcher at UNMA where he recently won the Outstanding Teacher of the Year award. He was honored by Can-Fit-Pro as the 1999 International Presenter of the Year and the 2006 Specialty Presenter of the Year. He was also chosen as the American Council on Exercise 2006 Fitness Educator of the Year.
Burdette, H.L., & Whitaker, R.C. 2005. Resurrecting free play in young children. Archives of Pediatric Adolescent Medicine, 159, 46–50.
Dietz, W.H., & Gortmaker, S.L. 1985. Do we fatten our children at the television set? Obesity and television viewing in children and adolescents. Pediatrics, 75 (5), 807–12.
Ebbeling, C.B., Pawlak, D.B., & Ludwig, D.S. 2002. Childhood obesity: public-health crisis, common sense cure. The Lancet, 360, 473–82.
Hedley, A.A., et al. 2004. Prevalence of overweight and obesity among U.S children, adolescents and adults, 1999–2002. Journal of the American Medical Association, 291 (23), 2847–50.
Janssen, I., et al. 2005. Comparison of overweight and obesity prevalence in school-aged youth from 34 countries and their relationships with physical activity and dietary patterns. Obesity Reviews, 6, 123–32.

Health Conditions Associated With Childhood Obesity

SIDEBAR: The following physical conditions and diseases have been shown to be directly related to childhood obesity:
• abnormal blood lipids
• atherosclerosis
• chronic inflammation
• elevated insulin levels
• endothelial dysfunction
• heart disease
• hypertension
• increased tendency for blood clotting
• kidney dysfunction
• liver dysfunction
• neurological complications
• type 2 diabetes
Source: Ebbeling, C.B., Pawlak, D.B., & Ludwig, D.S. 2002. Childhood obesity: public-health crisis, common sense cure. The Lancet, 360, 473–82.

The Psychological Effects of Childhood Obesity

In addition to the physical toll that obesity takes on children, there are damaging psychological effects. Here are some of them:
• adoption of high-risk behaviors
• decline in self-esteem
• loneliness
• nervousness
• sadness
• negative self-image
Source: Ebbeling, C.B., Pawlak, D.B., & Ludwig, D.S. 2002. Childhood obesity: public-health crisis, common sense cure. The Lancet, 360, 473–82.

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About the Authors

Doyeon Kim, MS

Doyeon Kim, MS IDEA Author/Presenter

Len Kravitz, PhD

Len Kravitz, PhD IDEA Author/Presenter

Len Kravitz, PhD, is the program coordinator of exercise science and a researcher at the University of New Mexico in Albuquerque, where he recently won the Outstanding Teacher of the Year award. Len was also honored as the 2006 Fitness Educator of the Year by the American Council on Exercise.