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Obesity and Overweight: Condition Information

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What are obesity, overweight, and body composition?

Body composition is a term that describes how much of a person’s body is made up of bone, fat, water, and other substances. “Overweight” and “obesity” both mean that a person is at an unhealthy weight. An obese person has too much body fat. An overweight person weighs too much, but the extra weight may come from muscle, bone, body water, and/or fat.1

Health care providers often use body mass index (BMI) to determine if a person is overweight or obese. Adults who have a BMI between 25 and 29.9 are generally considered overweight. Adults who have a BMI of 30 or higher are considered obese.2 A child’s weight status is determined using a special chart that takes into account the child’s age and gender.3 Learn more about BMI and other measurements of overweight and obesity.


  1. National Library of Medicine. (2012). Obesity. Retrieved August 8, 2012, from MedlinePlus: http://www.nlm.nih.gov/medlineplus/obesity.html [top]
  2. Centers for Disease Control and Prevention. (2012). Overweight and obesity: Defining overweight and obesity. Retrieved August 8, 2012, from http://www.cdc.gov/obesity/adult/defining.html [top]
  3. Centers for Disease Control and Prevention. (2012). Overweight and obesity: Basics about childhood obesity. Retrieved August 8, 2012, from http://www.cdc.gov/obesity/childhood/basics.html [top]

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