Childhood Obesity

  • Medical Author:
    John Mersch, MD, FAAP

    Dr. Mersch received his Bachelor of Arts degree from the University of California, San Diego, and prior to entering the University Of Southern California School Of Medicine, was a graduate student (attaining PhD candidate status) in Experimental Pathology at USC. He attended internship and residency at Children's Hospital Los Angeles.

  • Medical Editor: David Perlstein, MD, MBA, FAAP
    David Perlstein, MD, MBA, FAAP

    David Perlstein, MD, MBA, FAAP

    Dr. Perlstein received his Medical Degree from the University of Cincinnati and then completed his internship and residency in pediatrics at The New York Hospital, Cornell medical Center in New York City. After serving an additional year as Chief Pediatric Resident, he worked as a private practitioner and then was appointed Director of Ambulatory Pediatrics at St. Barnabas Hospital in the Bronx.

An epidemic is defined as occurring when "new cases of a certain disease, in a given human population during a given time period, substantially exceed what is expected based upon recent experience." Pediatric obesity has reached epidemic proportions when compared with just 20 years ago. The goal of this article is to explore this phenomenon and understand the potential consequences should this pattern continue. The concurrent epidemic of adult obesity will not be addressed.

Childhood obesity facts

  • Adult and childhood obesity have increased substantially in the last 30 years. Currently, 35% of adults (78.6 million) and 18% of children 2 to 19 years old (12.7 million) are obese, as defined by their body mass index (BMI).
  • The vast majority of obesity represents an imbalance in calories ingested versus calories expended. Other causes of obesity (metabolic, medicines, and other diseases) are very rare.
  • Losing body fat requires both caloric restriction and daily vigorous exercise.
  • The immediate and long-term consequences of obesity include physical, psychological, and economic issues.
  • Obesity prevention will require both a personal and social/cultural change in lifestyle. The large volume of current research will help clarify what will be most helpful.
  • Recent evidence supports that child obesity rates have leveled off and are even decreasing in the younger age groups.

What is childhood obesity? How do health-care professionals diagnose childhood obesity?

In order to systematically describe obesity, the concept of body mass index (BMI) was developed. BMI is the ratio between an individual's weight to height relative to their gender and age. BMI addresses the following question: Is the weight of the subject in excess of what is healthy for a given height? Generally (but not always), BMI correlates with the amount of body fat, but it is not a measurement of fat. An individual who has more than the average muscle mass for a given height (for example, weightlifters) will have an elevated BMI but clearly will not be obese. Nomograms for both adults and children have been developed to graphically represent the range of normal when measuring BMI. An individual is overweight when their BMI is between 25.0-29.9. Obesity is defined as a BMI greater than 30.0. Many web sites have calculators to measure BMI (for example, http://www.cdc.gov/healthyweight/assessing/bmi/). Measuring body fat may be done via skin-fold-thickness measurement, waist-to-hip-circumference ratio, and neutral buoyancy (water displacement) measurements. BMI is not used for children under 2 years of age, and instead growth charts should be used to identify any weight issues.

Childhood Obesity Quiz: Test Your Medical IQ
Learn about prevention of childhood obesity.

Childhood Obesity Prevention Tips

Q: I'm pregnant and have a family history of obesity. How can I prevent my child from becoming obese?

A: A report from the Institute of Medicine this year found that one-third of American children and youths are either obese or at risk for obesity. Over the past 30 years, the obesity rate has nearly tripled for children 2-5 years old (from 5% to 14%) and youths 12-19 years old (5% to 17%), and it has nearly quadrupled for children 6-11 years old! We now know that infants are at greater risk for obesity if their moms gain excessive weight during pregnancy.

How prevalent is childhood obesity?

The national statistics regarding childhood obesity prevalence (total number of cases in the pediatric population) have risen remarkably. In the 1970s and 1980s, approximately 5% of children were obese. By 2000, over 13% were obese, and 2010 statistics indicate pediatric obesity to be leveling off at approximately 18% of the population. (In contrast, approximately 35% of adults are obese.) While the frequency of obesity appears to be leveling off, the amount of excess weight has continued to rise (for example, BMI value has risen higher per individual).

The Midwest and South have the highest frequency of obesity (31%), with Arkansas, Mississippi, and West Virginia having the highest frequency (36%) and Colorado having the lowest (21%). Of the remaining states, 26 have an obese population of over 25%; 18 states have over 30% of their population being obese. In 2000, no states had more than 30% of their population considered obese. As of 2014, no state had less than 20% of its adult population classified as obese.

The Centers for Disease Control and Prevention's web site (http://www.cdc.gov) has an excellent demonstration of the rise in obesity over the last 30 years by using an interactive map of the United States (http://www.cdc.gov/obesity/data/trends.html#State).

An area of concern is that the statistics gathered in many studies are self-reported by the individual and may therefore be overly optimistic (for example, purposely underestimating weight and overestimating height).

What causes childhood obesity?

Most obesity is caused by excessive daily caloric intake relative to daily caloric expenditure. Excessive intake of calories is most commonly associated with poor food-quality choices (for example, fast-food high in fat and sugar calories) but may also result from over-ingestion of "healthy foods." The simple biological fact is that all excessive calories (regardless whether triple cheese meat lovers pizza vs. fat free yogurt with berries) will be stored by the body and only as fat. Attempts at only reducing caloric intake without increasing caloric utilization (read: 60 minutes daily vigorous exercise) will only help temporarily. If calorie restriction is the sole approach toward losing weight, the body's metabolism adopts a conservation mode and learns how to get by on fewer calories. Adding physical activity to the calorie-burning equation encourages breakdown of excessive carbohydrate and fat stores, allowing for more functional and long-term health.

Body weight (not necessarily excessive body fatness) is a reflection of genes, metabolism, behaviors, culture, and socioeconomic status. These relatively infrequent causes of obesity will be detailed below.

What are childhood obesity symptoms and signs?

Measurement of height and weight are the most commonly used tools to quickly evaluate the proportionality of children. These measurements allow calculation of the body mass index (BMI). It is important to consider the physique of the individual. While having a weight in excess of what would be expected for a certain height is most commonly a documentation of excessive fat tissue, certain individuals may be overmuscled (for example, weightlifters). With the exception of very rare bone diseases, the idea of an individual's excessive weight due to being "big boned" is an urban myth.

What are risk factors for childhood obesity?

There are several substantial risk factors for the development of pediatric obesity.

  1. Genetics: While several genetic syndromes are associated with obese stature (for example, Prader-Willi syndrome), genetics are not responsible for the obesity epidemic currently taking place. There has been no change in the gene pool over the last 30 years. Most recent studies indicate that if one parent is obese, the likelihood of having an obese child is three times higher than otherwise. If both parents are obese, the likelihood is 10 times higher.
  2. Social: Limited school athletic activities coupled with excessive time-utilizing social networks, TV, and computer games are a prime reason for pediatric obesity. Watching TV while eating a meal as well as the excessive consumption of takeout/fast food are also both risk factors for both pediatric and adult obesity. Recent studies indicate that only 20% of children experience more than two episodes of vigorous play per week, and 30% of these children watched more than two hours of TV per day. This does not include additional time engaging in computer games, texting, or talking on the phone with friends. Having a TV in the bedroom is a strong predictor of pediatric obesity.
  3. Cultural: Many societies follow either a healthier food palate (traditional oriental, Mediterranean, etc.) or eat smaller portions of higher-fat-content foods (European). The Americanization of such foods coupled with excessive portions is a prime cause of obesity.
  4. Diseases: Thyroid disease, polycystic ovary disease, brain tumors, mental retardation, and other conditions are a small contributor to the risk factors for obesity.
  5. Medications: Chronic oral steroids, some classes of antidepressants, and other drugs may also contribute (in a very small way) to pediatric obesity.
  6. Psychological: Many individuals overeat in an attempt to deal with emotionally stressful lifestyles. Often the excessive weight further aggravates their emotional turmoil.
  7. Increase in frequency of some cancers -- endometrial, breast, colon, kidney, gallbladder, and liver

What are the risks, complications, and long-term health effects of childhood obesity?

The consequences of childhood obesity may be grouped into three areas: physical, mental, and economic. The known physical side effects of obesity are multiple and broad spectrum in character. These include the following:

  1. Increase in risk of developing type 2 diabetes mellitus due to excessive insulin secretion and organ resistance to insulin
  2. Menstrual irregularity and infertility
  3. Heart attack and stroke due to hypercholesterolemia, hyperlipidemia, and hypertension
  4. Pulmonary issues centering on asthma and obstructive sleep apnea
  5. Orthopedic issues of bowed legs and hip instability (for example, slipped capital femoral epiphysis)
  6. Metabolic issues (nonalcoholic fatty liver disease, gallstones, and gastroesophageal reflux [GERD])

Equally as important as these physical side effects of obesity are the psychological consequences, which include the following:

  1. Lowering of self-esteem often reinforced by teasing and bullying at school as well as a recurring barrage of the normal/ideal physique displayed by the media and entertainment industries
  2. Depression, leading to possible further eating or an exaggerated overcorrection leading to eating disorders such as bulimia and anorexia nervosa

The economic costs of childhood obesity are not often considered but are very important. Such effects include the following:

  1. The direct costs of medical office visits, diagnostic studies, and therapeutic services
  2. Indirect costs are both long- and short-term and include decrease in productivity, absenteeism, and premature death. Researchers estimate that over $147 billion are spent annually on the direct and indirect costs associated with obesity.
Childhood Obesity Quiz: Test Your Medical IQ

What is the treatment for childhood obesity?

The treatment for childhood obesity is no different than many diseases -- determine the cause(s) and control or eradicate it (them). Since the overwhelming number of obese individuals are consuming too many calories relative to their energy expenditure ("burning them off"), therapy is directed toward reversing this metabolic equation. Simply put, consume fewer calories and use more up. There are many dietary programs that attempt to address this issue. None is superior over the long term unless the participant embraces these nutritional changes as part of a larger lifestyle recommitment. Drugs and surgery should be restricted to severe cases of childhood (and adult) obesity.

Is it possible to prevent childhood obesity?

Benjamin Franklin's famous dictum "an ounce of prevention is worth a pound of cure" is ironically the perfect approach to childhood obesity. The CDC has recently raised the notion that should the alarming increase in childhood obesity not be reversed, the consequences may make the current pediatric population be the first generation to not exceed the life span of their parents. Studies have indicated that childhood obesity must be attacked prior to the teen years. Twenty percent of obese 4-year-old children will grow up to become obese adults; 80% of obese teens will continue their obesity into adulthood. All of the above-reviewed consequences of pediatric obesity are brought forward into the adult years. Here are three amazing observations: (1) children 6 months to 6 years of age watch an average of two hours of television per day; (2) 18% of children less than 2 years old have a TV in their bedroom. Of this toddler population, 34% watched more than two hours of TV daily; (3) children 8-18 years of age spend an average of seven and a half hours per day involved with entertainment media activity such as television, computer games, video games, and cell-phone calls/texting.

Social and cultural changes are necessary to effectively address the pediatric obesity epidemic. A basic approach would entail the following:

  1. Advocate breastfeeding during the first year of life. Studies strongly reinforce that breastfed children have a lower risk of infant, childhood, and adolescent obesity.
  2. Drastically overhaul the school breakfast and lunch programs to favor heart-healthy food choices. Encouraging salad bars, banning sugar drinks, and flavored milk are options.
  3. Guarantee safe neighborhood environments which foster outside play activities.
  4. Limit TV/computer/social-network communication or other activities which encourage sedentary behaviors.
  5. Encourage vigorous physical education programs for 60 minutes daily.
  6. Revamp restaurant portion sizes. Studies had repeatedly demonstrated a link to the rise in pediatric obesity with fast-food restaurants' adoption of supersized portions as well as the bundling of food options (for example, deals for hamburger, french fries, and soda).
  7. Encourage the development of activity-friendly infrastructure in communities -- bike lanes, regional parks, etc. Many studies have shown that the social and cultural changes above must be accompanied by a strong family and community support structure, without which these approaches often fall short.
  8. Encourage avoidance of "empty carbohydrate" calories (for example, high fructose corn syrup) and emphasize "healthy fats" (for example, olive oil) in lieu of saturated fats/oils.

What research is being done on childhood obesity?

The National Institutes for Health (NIH) web site lists over 300 open studies currently focused on the pediatric age range (http://clinicaltrials.gov/search/
open/term=obesity+%5BCONDITION%5D+AND+child+%5BAGE-GROUP%5D
). These studies are exploring the various causes and associations of obesity, the physical, emotional, and financial impact of pediatric obesity, as well as a broad array of management tools, potential medications, and other therapies for the treatment of childhood obesity.

Where can people find more information on childhood obesity?

Accurate and timely information regarding pediatric obesity may be found at the following web sites:

Centers for Disease Control and Prevention (CDC)
http://www.cdc.gov/obesity/childhood/
index.html

http://www.cdc.gov/HealthyYouth/obesity/
index.htm

American Dietetic Association
http://www.eatright.org

National Institutes for Health (NIH)
http://www.nlm.nih.gov/medlineplus/
obesityinchildren.html

REFERENCES:

American Academy of Pediatrics (AAP). "Prevention and Treatment of Childhood Overweight and Obesity." <http://www.aap.org/obesity/index.html>.

American Dietetic Association. <http://www.eatright.org>.

United States. Centers for Disease Control and Prevention. "Childhood Obesity." June 3, 2010. <http://www.cdc.gov/HealthyYouth/obesity/index.htm>.

United States. Centers for Disease Control and Prevention. "Childhood Overweight and Obesity." Apr. 29, 2011. <http://www.cdc.gov/obesity/childhood/index.html>.

United States. National Institutes for Health (NIH). "Obesity in Children." <http://www.nlm.nih.gov/medlineplus/obesityinchildren.html>.

Childhood Obesity Quiz: Test Your Medical IQ

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Reviewed on 1/29/2016
References
REFERENCES:

American Academy of Pediatrics (AAP). "Prevention and Treatment of Childhood Overweight and Obesity." <http://www.aap.org/obesity/index.html>.

American Dietetic Association. <http://www.eatright.org>.

United States. Centers for Disease Control and Prevention. "Childhood Obesity." June 3, 2010. <http://www.cdc.gov/HealthyYouth/obesity/index.htm>.

United States. Centers for Disease Control and Prevention. "Childhood Overweight and Obesity." Apr. 29, 2011. <http://www.cdc.gov/obesity/childhood/index.html>.

United States. National Institutes for Health (NIH). "Obesity in Children." <http://www.nlm.nih.gov/medlineplus/obesityinchildren.html>.

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