Childhood obesity has become a disturbing national epidemic and has grown considerably in the past two decades. The percentage of children and adolescents who are defined as overweight has more than doubled since the early 1970s. According to the Centers for Disease Control, about 15 percent of children and adolescents are now overweight. Ironically, obesity is among the easiest medical conditions to recognize but most difficult to treat. Overweight children are much more likely to become overweight adults unless they adopt and maintain healthier patterns of eating and exercise. In fact, 30% of adult obesity begins in childhood. Obesity accounts for more than 300,000 deaths a year and the annual cost to society for obesity is estimated at nearly $100 billion.

What is Obesity?

Obesity is defined as an excessively high amount of body fat in relation to lean body mass. Overweight refers to increased body weight in relation to height, when compared to some standard of acceptable or desirable weight. BMI or Body Mass Index is one important way of deriving desirable weight standards. According to the Centers for Disease Control and Prevention, BMI uses a mathematical formula, in which a person's weight in pounds is divided by the square of the person's height in inches and this result is then multiplied by 703.

For example, a 13 year old boy who weighs 190 lbs. and is 5'5'' tall would have a

BMI = [190/(65)(65)] x 703 = 31.6.

A BMI of 31.6 would then be plotted on a BMI-for-age and gender specific growth chart (see As of August 2003, the American Academy of Pediatrics has adopted its first policy dealing with the identification and prevention of childhood obesity by urging pediatricians to check BMI yearly. In children and teens, body mass index is used to assess underweight, overweight, and risk for overweight. BMI between 85th and 95th percentile for age and sex is considered at risk of overweight, and BMI at or above the 95th percentile is considered overweight or obese.

What causes Obesity?

Genetics, nutrition, physical activity and family factors all contribute to obesity in children and adolescents. If one parent is obese, there is a 50 percent chance that a child will also be obese. However, when both parents are obese, a child has an 80 percent chance of being obese. Although the genetic influences are significant, it is important to recognize that poor eating habits and overeating, lack of exercise, and family eating patterns and pressures also contribute to the inability to maintain a healthy weight.

What are the Health Effects?

Overweight children, as compared to children with a healthy weight, are more likely to develop many health problems such as high cholesterol and high blood pressure, which are associated with heart disease in adults. Type 2 diabetes, previously considered an adult disease, has increased dramatically in overweight children and adolescents. Children at a healthy weight are free of these weight-related diseases and less at risk of developing these diseases in adulthood.

What are the Mental Health Effects?

The most immediate consequence of being overweight as perceived by children themselves is social discrimination and low-self-esteem. In a recent study by Schwimmer, (2003), obese children rated their quality of life with scores as low as those of young cancer patients on chemotherapy. In the study, 106 children aged 5 to 18 filled out a questionnaire used by pediatricians to evaluate quality of life issues. Children were asked to rate things like their ability to walk more than one block, play sports, sleep well, get along with others and keep up in school. The results indicated that that teasing at school, difficulties playing sports, fatigue, sleep apnea and other obesity-linked problems severely affected obese children's well-being. Interestingly, parents answered the same questionnaires, and their ratings of their children's well-being were even lower than the children's self-ratings.

Girls vs. Boys

Society, culture, and the media send children powerful messages about body weight and shape ideals. For girls, these include the "thin ideal" and an urging to diet and exercise. Messages to boys emphasize a muscular, "buff" body and pressure to body build and perhaps make use of potentially harmful dietary supplements and steroids. While gender has not been identified as a specific risk factor for obesity in children, the pressure upon girls to be thin may put them at greater risk for developing eating disordered behaviors and or related mood symptoms. Although society presents boys with a wider-range of acceptable body images, they are still at risk for developing disordered eating and body image disturbances.

What Can Parents Do?

According to the U.S. Surgeon General's "Call To Action To Prevent and Decrease Overweight and Obesity:

  • Obese children need a thorough medical evaluation by a pediatrician to consider the possibility of a physical cause.
  • In the absence of a physical disorder, the only way to lose weight is to reduce the number of calories being eaten and to increase the child's or adolescent's level of physical activity.
  • Emphasize healthy eating, keep fatty and sugary snacks to a minimum and keep fruits, vegetables and low-fat snacks available
  • Increase physical activity, perhaps by taking a few brisk walks with your child each week
  • Let your child know he or she is loved and appreciated whatever his or her weight. An overweight child probably knows better than anyone else that he or she has a weight problem. Overweight children need support, acceptance, and encouragement from their parents.
  • Be a good role model for your child. If your child sees you enjoying healthy foods and physical activity, he or she is more likely to do the same now and rest of his or her life.

About the Authors

Lauren Marcus, Ph.D., is the Assistant Director of the Family Studies Program at the New York University Child Study Center.

Amanda Baron, M.S.W., is an Assistant Research Scientist in the Institute for Prevention Science at the New York University Child Study Center.

References and Related Books


Centers for Disease Control and Prevention

Office of the U.S. Surgeon General

American Academy of Child and Adolescent Psychiatry (AACAP) 

Journal Articles

Riccairdelli, L.A., McCabe, M.P., Banfield, S (2002).Body image and body change methods in adolescent boys: Role of parents, friends and the media, Journal of Psychosomatic Research , 49 (3):189-197.

Schwimmer, J.B., Burwinkle, T.M and Varni, J.W., (2003), Health-Related Quality of Life of Severely Obese Children and Adolescents, JAMA 289: 1813-1819 .

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About the NYU Child Study Center

The New York University Child Study Center is dedicated to increasing the awareness of child and adolescent psychiatric disorders and improving the research necessary to advance the prevention, identification, and treatment of these disorders on a national scale. The Center offers expert psychiatric services for children, adolescents, young adults, and families with emphasis on early diagnosis and intervention. The Center's mission is to bridge the gap between science and practice, integrating the finest research with patient care and state-of-the-art training utilizing the resources of the New York University School of Medicine. The Child Study Center was founded in 1997 and established as the Department of Child and Adolescent Psychiatry within the NYU School of Medicine in 2006. For more information, please call us at (212) 263-6622 or visit us at