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Conditions InDepth: Obesity
Obesity is a high amount of body fat. It leads to a much higher body weight than normal. Calories are burned through activity and body functions. Weight gain happens when the calories eaten are more than the calories used. If this happens often, it leads to obesity.
Obesity is a body mass index (BMI) of 30 or higher in an adult. Severe obesity is a BMI that is higher than 40. BMI is a person’s weight in kilograms divided by the square of height in meters
Children and teens are still growing. Their BMI is measured differently than adults. Their BMI levels are expressed in how they compare to other children of the same gender and age. Obesity in children is a BMI at or higher than in the 95th percentile. This means the child's BMI is higher than 95% of kids the same age and gender. Severe obesity is when it is at or higher than the 120th percentile.
Health Problems from Being Obese
Without treatment, obesity can raise the risk of serious health problems, such as:
- Heart disease, such as coronary artery disease (CAD) and stroke
- Type 2 diabetes
- Some types of cancer, such as liver, kidney, thyroid, colon, and rectal
- Gastrointestinal diseases, such as gastroesophageal reflux disease (GERD), gallstones, and liver disease
- Sleep apnea
- Joint problems and back pain
- Problems during pregnancy, such as high blood pressure and blood clots
Heymsfield SB, Wadden TA. Mechanisms, Pathophysiology, and Management of Obesity. N Engl J Med. 2017;376(3):254-266.
Obesity in adults. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/obesity-in-adults. Accessed May 5, 2022.
Obesity in children and adolescents. EBSCO DynaMed website. https://www.dynamed.com/condition/obesity-in-children-and-adolescents. Accessed May 5, 2022.
Obesity. Merck Manual Professional Version website. Available at: http://www.merckmanuals.com/professional/nutritional-disorders/obesity-and-the-metabolic-syndrome/obesity. Accessed May 5, 2022.
Treatment. National Heart, Lung, and Blood Institute website. Available at: https://www.nhlbi.nih.gov/health/health-topics/topics/obe/treatment. Accessed May 5, 2022.
- Reviewer: EBSCO Medical Review Board Daniel A. Ostrovsky, MD
- Update Date: 05/04/2022