Epidemiology of Obesity Among Children in the United States
Childhood obesity has been identified as a critical medical and public health problem due to both an increase in prevalence of overweight and obesity among children and the increased risk for obesity-associated diseases and conditions in these children. Reports from the National Health and Nutrition Examination Survey (NHANES) by the Centers for Disease Control and Prevention (CDC) estimate that 31.8% of the US pediatric population, 2 to 19 years old, were overweight in 2011–12, and 16.9% were obese. The incidence of overweight and obesity has tripled in the United States over the past 3 decades, leading to the prediction that the current generation of children will have a shorter life expectancy than that of their parents. Also alarming is the increasing prevalence of extreme obesity among children, with 6% of youth aged 2 to 19 years old meeting that criteria in 2013–14. Children who have extreme obesity are at particularly high risk for developing obesity-associated comorbidities and diseases, including some that were previously considered only of adult onset, such as type 2 diabetes.
The incidence of both overweight and obesity increases as children get older. Many physicians recommend greater efforts to prevent the development of obesity starting in early childhood to reverse this troubling trend. Ethnic minority children in the United States, specifically Hispanic and non-Hispanic black children, are at greatest risk for overweight and obesity. Health disparities due to differences in access to healthy environments, resources, and health care may be contributing to this difference in prevalence. A child’s weight status is influenced by a combination of genetic, behavioral, environmental, and psychosocial variables. Interventions that attempt to prevent or treat obesity among children need to consider the complex interactions of these variables and ensure that the underlying factors for the current health disparities in obesity rates are addressed.
Pathophysiology of Weight Regulation
Weight gain typically is considered as being related simply to the imbalance between energy intake and energy expenditure. However, this simple energy balance equation is heavily influenced by very complex mechanisms. Most people are aware that physical activity is important in increasing energy expenditure and, not unexpectedly, the weight gain of the Western world has paralleled a decrease in overall activity levels. New research has shown that small increments of exercise throughout the day are equivalent to larger sessions. Nutritional choices influencing energy intake are also important. Previously, high-fat diets were thought to be a culprit of the obesity epidemic. Current research is mixed on the role of total fat and fat subtypes in mediating excessive weight gain and, more importantly, shows a probable role of refined carbohydrates in accelerating weight gain. Additionally, sleep has an important role in maintaining a healthy weight through the establishment of normal circadian rhythms.
The brain is also vitally important in maintaining an individual’s ...