What Are You Really Made Of?

  • 2 Minutes Read

Weighing yourself on your bathroom scale regularly and noticing how your pants fit are good ways to tell if your weight is headed in the right direction; however, you can find out "what are you really made of" through the gold standard of a DEXA scan.

What Are You Really Made Of?

By relaxing and lying on my back for six minutes and having my body scanned with a DEXA machine, I learned not only about the composition of my total body weight, but I also learned where the fat and lean body tissue were distributed in five different regions of my body. Since I am a right-handed tennis player, recently turned pickleball player, I was curious whether there would be more muscle on my right arm than my left arm.

The DEXA scan (DXA) is the gold standard in terms of telling you accurately about the composition of your weight because it determines what percentage is lean body mass (such as muscles and bones) and what percentage is fat. Especially if you are starting an exercise program, getting a DEXA scan at the beginning of your program, and then after 90 days, is an objective way to measure how your body composition is changing. Since muscle weighs more than fat, the scale may show that your weight is increasing; however, you are actually headed in a healthier direction because you now have a lower percentage of body fat.

Risk of high body fat

You have probably heard of apple-shaped and pear-shaped people. Those who are apple-shaped have more fat distributed around and between organs, such as the kidney, heart, and liver. Having fat in these visceral areas is associated with increased risk of type two diabetes, cardiovascular disease and high blood pressure. Decreasing your body fat through exercise can decrease your risk of those diseases.


In the1990's, the gold standard for body composition was called underwater weighing. I remember putting on my swim suit for a physical fitness class, and literally putting my head under the water and blowing out as much air as I could from my lungs to improve the accuracy of the measurements.

DEXA which stands for dual x-ray absorptiometry was originally only used to measure bone mineral density to assess whether a person was at higher risk for a fracture due to weak or brittle bones. However, since the DEXA scan is able to differentiate between fat and muscle tissue as well, today it is considered the gold standard of body composition with an error rate of 1-2%, plus you can stay completely clothed.


If you want to know my DEXA results as a right-handed tennis player, my right arm does have more muscle mass than my left arm.



Weighing yourself on your bathroom scale regularly and noticing how your pants fit are good ways to tell if your weight is headed in the right direction. However, if you ever wondered what percentage of your body is fat and what percentage is muscle and how your body composition is distributed in your body, consider the gold standard of a DEXA scan to find out what you are really made of!

Weight Loss->Body composition
May 1, 2019
Martha M. Henze
Martha M. Henze, MPH, MS, RDN - Registered Dietitian Nutritionist and Global Public Health Epidemiologist

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