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by EBSCO Medical Review Board

Diagnosis of Obesity

The doctor will ask about symptoms and past health. A physical exam will be done. Weight and height will be measured.
Obesity is a body mass index (BMI) of 30 kg/m² or higher in an adult. BMI is a person's weight in kilograms divided by the square of their height in meters. Severe obesity is a BMI that is higher than 40.
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 in the 95th percentile or higher. This means the child's BMI is higher than 95% of kids the same age and gender. Severe obesity is when it is in the 120th percentile or higher
Obesity can also be diagnosed by measuring a person's waist. Having a large waist can raise the risk of health problems. This can happen even if a person's total weight is not high.


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.

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