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The percentage of overweight children in the United States has more than tripled since 1980 with the greatest impact occurring among minority and economically disadvantaged children.1 Globally, it is currently estimated that 1 in 10 school-aged children is overweight (roughly 155 million children) and 30 to 45 million of those children are considered obese.2 For children under the age of 5 years, a further 22 million children are considered overweight.3 These findings suggest a very troubling future given that the likelihood of obesity persisting into adulthood increases from 20% at 4 years of age to 80% by adolescence and that obesity increases the risk for a myriad of weight-related health complications.4

To better understand the pathobiology of obesity, it is useful to review the process by which adipose tissue is created. From an evolutionary prospective, it is beneficial to store energy during periods of energy availability in preparation for very likely periods of food scarcity. The body stores the available excess energy in the form of triglycerides within fat cells that reside within the adipose tissue. This tissue is widely distributed throughout the body and can store a tremendous amount of excess energy. When food scarcity limits energy intake, the body then releases the stored energy in the form of free fatty acids, providing a survival advantage. A delicate balance exists, and even small, subtle changes in lifestyle can begin leading a person toward obesity. A small but regular increase in calories or cessation of a regular physical activity can tip the balance toward overweight and obesity. In our current Western environment, food scarcity is uncommon with readily available high-density caloric foods being relatively inexpensive.

The factors that influence an individual’s intake-to-expenditure ratio are nearly limitless. Children are confronted on a daily basis with a tremendous amount of marketing encouraging the consumption of high-calorie, high-fat, and high-sugar foods and drinks. They become progressively more sedentary as they are encouraged to engage in activities like video games, the Internet, and television. More subtle influences may include neighborhoods that are too dangerous for children to play outside, inadequate sleep, parents who do not model appropriate health behaviors, and governmental policies. These influences alter the child’s intake-to-expenditure energy ratio.

An individual’s genetics also plays a significant role in the development of weight and weight-related problems. Children who are adopted possess body mass indices that are more closely related to their biological than to their adoptive parents.5 Apart from genetic risk, an individual’s obesity risk is also shaped by the environment and biological factors, such as leptin, ghrelin, adiponectin, and other hormones that affect specific metabolic functioning, such as appetite, satiety, and fat distribution.6

Internationally, as cultures begin experiencing economic growth, technological advances, and increased modernization, including entering the global food market. Diet generally changes such that simple diets high in complex carbohydrates shift toward a more varied diet that contains higher amounts ...

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