For some time now the skeptical cardiologist has been obsessed with discovering the best tool to measure body fat.
It’s clear that the fat that gathers around our heart and within our abdomen, so-called visceral fat, has dire consequences for the cardiovascular system.
The standard way of measuring obesity, however, the body mass index doesn’t really tell us with high accuracy what is going on with visceral fat.
You can calculate your BMI using this online calculator. When I plug my numbers in I get a BMI of 22.3 which puts me in the “normal” range according to this chart from the NHLBI.
The BMI, however, is a very crude tool. A high BMI could be the result of a large amount of muscle mass, generally felt to be a good thing.
Conversely, it’s possible to have a normal BMI with a very high visceral fat percentage and low muscle mass. Such patients, the so-called “skinny fat” have the same risk as those with obesity as determined by BMI.
Due to perceived limitations of BMI as a predictor of body fat (and therefore true obesity), other methods of estimating body fat and/or visceral fat have been developed.
Waist Circumference and Waist Stature Ratio
Waist circumference (WC) is a simple, inexpensive and reliable test. Some studies have suggested WC correlates with visceral fat better than BMI. Despite recommendations that WC be made a routine measurement along with height and weight, very few doctors (including the skeptical cardiologist) have embraced routine WC measurement.
I measured my WC multiple times and it was always about 33 inches which puts me solidly under the 40-inch cut point for men. One study suggests the WC to stature ratio (WSR) is superior to WC and that we should aim for a ratio <0.5.
My ratio was slightly under 0.5.
It’s not clear to me that WC or WSR adds enough to BMI to justify performing it on my patients. A 2009 comparison of BMI, WC, and WSR to the gold-standard of dual x-ray absorptiometry (DEXA-scan) found that
BMI, WC, and WSR perform similarly as indicators of body fatness and are more closely related to each other than with percentage body fat
Using a special caliper it is possible to measure the thickness of the skin at various body locations. These measurements when normalized for age and gender give a fair estimate of body fat.
I purchased one of these devices a few years ago and made measurements on myself and many of my friends. When I added up my skinfold thickness from the anterior and posterior upper arm, the waist, and the shoulder blade regions I obtained a thickness of 29 mm. Using the chart that is shipped with the caliper, my fat % was calculated at 17.9%.
Many bathroom scales these days claim to measure fat mass, muscle mass at the same time they are weighing you. Such scales are using bioimpedance to infer body composition.
I have been using a QardioBase for my daily weights which gives me a readout that typically looks like this:
When I pulled up the chart below I realized that 24% body fat for men >60 years of age was at the upper range for healthy, bordering on “overfat.”
If I was a woman, on the other hand, I would be at the bottom end of the healthy range, bordering on “underfat.”
How Fat Am I?
After utilizing the commonly available modalities for assessing body fat, visceral fat, and obesity do we truly know how fat the skeptical cardiologist is?
BMI puts him solidly in the normal range.
Waist circumference puts him solidly in the normal range.
Waist to status ratio puts him close to obese.
Skinfold calipers give him normal body fat for age of 17.9%.
A bioimpedance scale gives him 24% body fat, bordering on “overfat.”
After undergoing a test last week I believe I can answer the burning question with confidence. More importantly, I believe I now have a convenient, inexpensive, and highly accurate tool that will provide precise estimates of my patient’s visceral body fat.
Empowered with such knowledge, hopefully, we can more successfully identify and treat cardiometabolic disease.
N.B. That is not my abdomen in the featured image.
11 thoughts on “How Fat Is The Skeptical Cardiologist?”
Last time I saw you, you looked quite fit, nice to see a cardiologist/MD who practice what they preach! On another note I do think its interesting the paradox of higher BMI’s and older age. On the superficial it appears that higher BMI might be better to be for older folks in a myriad of ways. However when looking at it further it might very well be related to where that fat is distributed, how much lean muscle mass an individual has and bone density, all of which are not really taken into account when calculating BMI using the calculators. Regarding fat, its amazing to me the evolution of knowledge of adipose tissue from being an inert tissue to be a highly metabolic and hormonal system that influences the short and long term health in a myriad of ways.
As a high schooler on vacation in the ’60s, I would envy my mother’s ability to float when ocean swimming. She could bob on her back with her toes out of the water in such an easy fashion that she sometimes fell asleep.
For me it was a struggle to keep just my face out of the water. In fresh water I simply sank.
I was told by my GP that I was overweight with a BMI of 26 to 27, a “dangerous situation”.
That GP was the danger.
Actually, Mom was well cushioned and I was not. I’d trained with weights for track & field throughout high school and had virtually no subcutaneous tissue, just muscle.
I was dense; Mom was not.
I float better now. 🙁
Years ago I realized that obesity is defined as “excessive body fat” and BMI and weight tell you nothing about the fat in your body. I purchased a Futrex 500 device that uses near infrared light and an FDA approved bioelectric impedance device. Over several decades I recorded over 10,000 body compostion readings. This is when I noticed the connection between changes in body fat and brain dysfunction symptoms leading me to propose a new disease called Carbohydrate Associated Reversible Brain syndrome or CARB syndrome. It appears this disease is triggered by long-term exposure to highly processed food and because the symptoms of CARB syndrome overlap with many traditional disorders, there has been a great deal of diagnostic and therapeutic confusion. I blog about this at: http://carbsyndrome.com/ and my new book “Brain Drain” discussed this in detail.
What about the water tank method? Is that it? Don’t want to steal your thunder….
I too have the same question….waiting with bated breath…..
I have a body mass index of 27. I am 74 years old and have been an endurance runner for years. I thought 27 was high so I went to the weight loss center at the local hospital to enroll in a weight loss program. The hospital used the TANITA measurement system with software that gave multiple measurements. My body fat % was 9, BMI 27, visceral fat ratting 6, body water % 38.4 and to make a long story short my muscle mass/score was 100.2. The nurse told me I had very high muscle mass for my height and total weight. The doctor then told me I did not need to lose weight because of my age and the fact that I show very little muscle wasting which is common in the elderly. The hospital did not accept me for a weight control program. Now, this cost me a chunk of money just to find out my BMI of 27 was good for my age and muscle mass. Maybe the skeptical cardiologist can get one of those TANITA weight measurement systems to use with his patients. The print outs give 16 variables including metabolic age. Great to have in the office but I bet it cost a fortune.
Thanks for the interesting and pertinent write up!
In the next to last paragraph you say and I quote “More importantly, I believe I now have a convenient, inexpensive, and highly accurate tool that will provide precise estimates of my patient’s visceral body fat”
Would you care to share what that method of measuring body fat is?
That will be revealed in my follow up post.
The scale reading is highly affected by hydration levels. Get a DXA-Scan and you’ll get closer to your truth.
Enjoyed this article, thanks for your good works.
Yes. I can see variations in the %fat depending on pre or post meals or exercise, as well as with full or empty bladder. But it is always >20%.
DEXA is also influenced by state of hydration.
Much simpler and a bit more difficult: If u have abdominal clear lines of demarcation, u r there. If not u need more exercise /% body fat reduction