Body Mass Index, Hieght-to-Weight Ratio and Body Fat. Oh my!
Do you weigh yourself on a regular basis? Well stop!
For one thing, it’s probably driving you nuts. For another thing, weight only gives you limited information.
There are progressively more complex ways of measuring your body fat, so let’s go over them.
Weight
Weight is the crudest measurement of all. Why? Because weight consists of not just fat, but also muscle, water, bone, blood, skin, connective tissue and more.
So if you go on a diet and you see the numbers on the scale go down, you’re happy. But don’t be. If all you’re doing is dieting, without resistance training, almost half the weight you lose is lean mass. The scale says you lost 10 pounds? Well only 5-6 of those pounds may be fat. The rest is lean mass.
You lose lean mass, you slow down your metabolism, weaken your bones, and compromise your immune system. Not good.
Body Mass Index
To figure out your Body Mass Index (BMI) you take your weight in kilograms, and divide by your height in meters squared. So let’s say you weigh 70 kilograms (154 pounds), and you’re 1.65m tall (about 5’5), that would make your Body Mass Index 25.7.
“Ideal” Body Mass Index is 18.9-24.9. Overweight is considered having a Body Mass Index of over 25.0. Obese is considered having a Body Mass Index of over 30.0.
The problem is similar to weight: it doesn’t take body fat into account. So somebody very muscular with low body fat would be classified as obese. Let’s take the Governator, Arnold Schwarzenegger. At the height of his bodybuilding career, he stood 6’2 and 240 pounds. His Body Mass Index would have been 30.8. Was he obese? Nope.
At the other end of the spectrum, we have people who are classified as “normal” or at their “ideal” weight, yet their body fat is extremely high. For example, in the past, I’ve measured a woman, who at 5’6 was 132 pounds. That would make her Body Mass Index 21.3. Yet her body fat was 34%! “Healthy” for a woman is considered 12-25%, over-fat is considered 26-30% and obese is considered over 30%.
This is when Body Mass Index can be dangerous, because people who are or “ideal” weight, but have high body fat percentage are not classified as at-risk. And yet, they are. They are at significant risk for osteoporosis, fractures, heart conditions, cancer and inflammatory conditions. More so than their overweight counterparts (who are at risk for other things).
Waist to Hip Ratio
The waist to hip ratio is a bit better than the previous 2 methods. It’s been proven very conclusively that any excess body fat is damaging to your health, but it’s particularly damaging when you store excess fat in your belly, especially under the muscle.
There are 2 types of fat: subcutaneous and visceral (this is what they look like: http://healthhabits.files.wordpress.com/2008/11/love-handles-vs-visceral-fat.jpg). Subcutaneous means “under the skin.” So when you see a flabby belly, that person has subcutaneous fat. When you see a big, round belly, but it’s not flabby, that’s visceral fat. Also known as “heart attack fat.”
So if you’re a man and your waist to hip ratio is greater than 1.0 or you’re a woman and your ratio is greater than 0.8, you’re at risk for heart disease.
The problem with waist to hip is that a big butt cancels out a big waist. So it may make you think that you’re not at risk for heart disease even though you most definitely are.
Waist to Height Ratio
The waist to height ratio is another step up. It takes the hips out of the picture. Both men and women want a ratio of less than 0.5. So if your waist is 32 inches, and you’re 5’6 (66 inches), you’re doing well.
Electronic Measuring Devices
Electronic measuring devices (technically called “bioelectrical impedance analysis”) basically send a little electricity through your body (don’t worry, you don’t feel anything), and they tell you how much fat you have. The theory is that electricity travels faster through muscle than through fat. So the more fat you have, the longer it will take the electricity to travel. This theory is correct.
Where it falls apart is that electricity also takes the shortest path between 2 points. So if you’re using a handheld device (like this: 
), it will only measure the fat between your 2 arms, and won’t take your belly, back and lower body into account. Likewise, if you’re using an electical scale (like this: 
), it only tells you your lower body fat.
Furthermore, the problem is these tools don’t tell you where your body fat is stored, which is critical.
Underwater Dunking
I wasn’t going to include this one, but I’m sure that someone will email me, saying this is the gold standard when it comes to body fat testing. It isn’t.
If you don’t know, there is a method of body fat testing where they dunk you under water (technically called “hydrostatic weighing”), and based on the amount of water that you displace, that’s how much fat you have (it looks like this: 
)
This was the gold standard more than 20 years ago, but it was based on a number of false assumptions.
The way the test is conducted is they make you exhale all the air you have. When you’re done exhaling, they instruct you to exhale some more. When you’re really done exhaling, they dunk you under water. The assumption was that whatever air you had in your lungs after you’re done exhaling (this is called your “residual volume”) was the same for each person. It isn’t. A 240-pound person will have a different residual volume than a 120-pound person. A swimmer will have a greater residual volume. A singer will have greater residual volume. A smoker will have lower residual volume.
The other false assumption is that fat is of the same density of all people. That’s not the case. Different people’s fat is of different density.
There are a number of other issues with this method, which are beyond the scope of this newsletter.
My Choice: Skinfolds Plus Circumferences Plus Weight
And now, my choice. If you’ve had your body fat measured and analyzed by either me or one of my trainers, you know how thorough this is. I’ve actually attached the sheet that me and my trainers use for body fat testing just so you can see how much information we’re extracting.
This is a very low-tech, high-effectiveness method.
How does it work?
We pinch 12 different sites with a skinfold caliper (it looks like this: 
), then we measure your circumferences at 6 different sites, and then we measure your weight.
Why do we make it so thorough? For a number of reasons:
- It tells you where fat is stored, which is critical.
- It allows you to see what’s happening in your body. If you just use circumferences, you’re not getting the full story. Let’s say that we measure the circumference of your right arm and it’s 30 cm. We measure it again in 4 weeks and it’s 32 cm. Did you gain muscle or fat? The correct answer is: you don’t know. Without the skinfolds, you don’t know. But let’s say that your circumference went from 30 cm to 32 cm and your skinfold went down from 24 mm down to 21 mm. That would mean the increase in your right arm is due to muscle. But let’s say that your circumference went from 30 cm to 32 cm and your skinfold went from 24 mm up to 27 mm. Then you’d know that the gain in circumference is from fat. For those of you who are confused, I apologize. Just read this section once again.
- Different areas will respond differently to different nutritional protocols. For example: eat more blueberries, spinach and red bell peppers, and your belly fat will decrease more than with other foods (even healthy foods). Eat more meat and fish, and the backs of your arms decrease. Eat more broccoli, brussels sprouts, cabbage and cauliflower, and your buns and thighs decrease. These are just the nutritional effects on different areas. We didn’t even touch on training and supplementation.
- I’ve written about this in past newsletters. You can learn more here: http://www.fitnesssolutionsplus.ca/2012/06/18/get-rid-of-belly-fat-should/
Quick Summary
Don’t use weight as a measure of your health. If you have access to an experienced tester, use skinfolds in combination with circumferences and weight. If you don’t have access to an experienced tester, use the waist-to-height ratio.
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Do you have any questions?
Email me, and I’d be happy to answer them.
Until next week,
Igor
647-271-8672
500 Denison St.,
Markham, ON
