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 Overweight and Obesity
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Contributing Factors

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.10 It is the interactions among these factors – rather than any single factor – that is thought to cause overweight.11

Genetic Factors

Photo of an overweight mother and daughterStudies indicate that certain genetic characteristics may increase an individual’s susceptibility to overweight.12, 13 However, this genetic susceptibility may need to exist in conjunction with contributing environmental and behavioral factors (such as a high-calorie food supply and minimal physical activity) to have a significant effect on weight. Genetic factors alone can play a role in specific cases of overweight. For example, overweight is a clinical feature for rare genetic disorders such as Prader-Willi syndrome.14 However, the rapid rise in the rates of overweight and obesity in the general population in recent years cannot be attributed solely to genetic factors. The genetic characteristics of the human population have not changed in the last three decades, but the prevalence of overweight has tripled among school-aged children during that time.8, 46

Behavioral Factors

Because the factors that contribute to childhood overweight interact with each other, it is not possible to specify one behavior as the “cause” of overweight. However, certain behaviors can be identified as potentially contributing to an energy imbalance and, consequently, to overweight.

Environmental Factors

Home, child care, school, and community environments can influence children’s behaviors related to food intake and physical activity.15

Tips for Parents
What can you do as a parent or guardian to help prevent childhood overweight? We have some ideas in our Healthy Weight section.

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Page last reviewed: May 22, 2007
Page last updated: May 21, 2008
Content Source: Division of Nutrition, Physical Activity and Obesity, National Center for Chronic Disease Prevention and Health Promotion