Obesity is an abnormally high proportion of body fat. The doctor can often determine if you are obese by looking at your body and assessing the percentage of body fat. Methods of assessing body fat are discussed below.
Measuring your weight in relation to your height is the traditional way of determining whether you are overweight, obese, or at an appropriate weight. Your doctor can often determine if you are overweight or obese by calculating your body mass index (BMI). This can be done by dividing your weight in kilograms by your height in meters squared. Your BMI can easily be calculated using a height and weight table. The BMI calculation does not take into account whether your weight is composed mostly of fat or muscle. Some muscular people may have a high BMI without being overweight or obese.
In addition, there is risk associated with abdominal fat build up, even if your total weight is not high. So measuring the circumference of your waist is also an important measure of whether you need to lose weight.
There are other tests that can estimate your percentage of body fat. The accuracy of these tests varies and some are so expensive that you are not likely to have them at the doctor’s office. When combined with your visual appearance and waist circumference, your BMI can usually provide a valid estimate of whether you are overweight or obese.
Methods to diagnose obesity:
Blood tests can be done to rule out other medical conditions that may cause excess body weight, such as thyroid or adrenal disorders
Barlow SE, Expert Committee. Expert committee recommendations regarding the prevention, assessment, and treatment of child and adolescent overweight and obesity: summary report. Pediatrics. 2007;120(Suppl):S164-S192.
Childhood overweight. Obesity Society website. Available at: http://www.obesity.org/resources/facts-about-obesity/childhood-overweight. Updated May 2014. Accessed February 23, 2017.
Diagnosis. National Heart, Lung, and Blood Institute website. Available at: https://www.nhlbi.nih.gov/health/health-topics/topics/obe/diagnosis. Updated February 23, 2017. Accessed February 23, 2017.
Obesity. Merck Manual Professional Version website. Available at: http://www.merckmanuals.com/professional/nutritional-disorders/obesity-and-the-metabolic-syndrome/obesity. Update December 2016. Accessed February 23, 2017.
Obesity in adults. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T115009/Obesity-in-adults. Updated November 20, 2016. Accessed February 23, 2017.
Obesity in children and adolescents. EBSCO DynaMed Plus website. http://www.dynamed.com/topics/dmp~AN~T115153/Obesity-in-children-and-adolescents. Updated January 30, 2017. Accessed February 23, 2017.
Last reviewed February 2017 by Michael Woods, MD, FAAP
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.