Overweight is a serious health concern for children and adolescents. Data from two NHANES (National Health and Nutrition Examination Surveys) surveys (1976–1980 and 2003–2004) show that the prevalence of overweight is increasing: for children aged 2–5 years, prevalence increased from 5.0% to 13.9%; for those aged 6–11 years, prevalence increased from 6.5% to 18.8%; and for those aged 12–19 years, prevalence increased from 5.0% to 17.4%.

Overweight children and adolescents are at risk for health problems during their youth and as adults. For example, during their youth, overweight children and adolescents are more likely to have risk factors associated with cardiovascular disease (such as high blood pressure, high
cholesterol, and Type 2 diabetes) than are other children and adolescents.2

Overweight children and adolescents are more likely to become obese as adults. For example, one study found that approximately 80% of children who were overweight at aged 10–15 years were obese adults at age 25 years. Another study found that 25% of obese adults were overweight as children. The latter study also found that if overweight begins before 8 years of age, obesity in adulthood is likely to be more severe.

Source: Centers for Disease Control: www.CDC.gov

At the individual level, childhood overweight is the result of an imbalance between the calories a child consumes as food and beverages and the calories a child uses to support normal growth and development, metabolism, and physical activity. In other words, overweight results when a child consumes more calories than the child uses. The imbalance between calories consumed and calories used can result from the influences and interactions of a number of factors, including genetic, behavioral, and environmental factors.

Childhood overweight is associated with various health-related consequences. Overweight children and adolescents may experience immediate health consequences and may be at risk for weight-related health problems in adulthood.

Some consequences of childhood and adolescent overweight are psychosocial. Overweight children and adolescents are targets of early and systematic social discrimination. The psychological stress of social stigmatization can cause low self-esteem which, in turn, can hinder academic and social functioning, and persist into adulthood.

Overweight children and teens have been found to have risk factors for cardiovascular disease (CVD), including high cholesterol levels, high blood pressure, and abnormal glucose tolerance.39 In a population-based sample of 5- to 17-year-olds, almost 60% of overweight children had at least one CVD risk factor while 25 percent of overweight children had two or more CVD risk factors.

Less common health conditions associated with increased weight include asthma, hepatic steatosis, sleep apnea and Type 2 diabetes.

* Asthma is a disease of the lungs in which the airways become blocked or narrowed causing breathing difficulty. Studies have identified an association between childhood overweight and asthma.

* Hepatic steatosis is the fatty degeneration of the liver caused by a high concentration of liver enzymes. Weight reduction causes liver enzymes to normalize.

* Sleep apnea is a less common complication of overweight for children and adolescents. Sleep apnea is a sleep-associated breathing disorder defined as the cessation of breathing during sleep that lasts for at least 10 seconds. Sleep apnea is characterized by loud snoring and labored breathing. During sleep apnea, oxygen levels in the blood can fall dramatically. One study estimated that sleep apnea occurs in about 7% of overweight children.

* Type 2 diabetes is increasingly being reported among children and adolescents who are overweight. While diabetes and glucose intolerance, a precursor of diabetes, are common health effects of adult obesity, only in recent years has Type 2 diabetes begun to emerge as a health-related problem among children and adolescents. Onset of diabetes in children and adolescents can result in advanced complications such as CVD and kidney failure.

source: http://www.cdc.gov/nccdphp/dnpa/obesity/childhood/index.htm