What are the patterns of obesity during middle childhood?

The American Heart Association (2007) defines obesity in terms of not only weight but also body composition, or the amount of muscle and fatty tissue. Given these criteria, research studies indicate that between 16 and 25% of American children are obese.
Contributing factors include an increase in television viewing (and the number of commercials advertising high fat and high sugar foods) and a decline in the number of families engaging in physical activity as a part of their family interactions.