Why Calculate Body Fat Percentage? For Smart Weight Control, Of Course!
Why Calculate Body Fat Percentage?
Well, really simple.
I get these results:
- What my correct weight should be
- How much fat I've
- How much muscle I've and
- What exactly I need to gain or lose
I can then design an exercise program to maximize my effort!
The other thing is that body fat calculation is an important tool to help me have a successful weight control program.
Body Fat Explained
What's body fat?
To explain it, I need to distinguish between 2 types of fat:
- Essential body fat
- Excess body fat
Essential body fat is necessary to maintain life and to reproduce. For us ladies, we require at least 8% - 12% of our body weight to be essential fat, to maintain life and keep us going. We've essential body fat in our lungs, liver, heart, bone marrow, kidneys, spleens, nerve tissue, brain and cell membranes.
Excess body fat is simply fat that we store. We store this fat in the tissue between muscle and skin.
We need some excess body fat to protect our bones and organs, to insulate our body from cold and heat and to maintain a good core body temperature.
For us ladies, average stored body fat is 15% - 20% of our total body weight and we're in trouble when this figure rises above 35%.
If we've too much of this fat, we'll have higher risk of having high blood pressure, heart disease, diabetes, gall bladder disease and certain kinds of cancer.
On the opposite, too little of this fat isn't a good thing either as it leads to disruption of menstrual cycle (amenorrhea), anemia, slow heart rate, decreased cardiac output, low blood pressure and low white blood cell count.
In short, we've to balance our body's stored fat - not too much and not too little.
That's why calculate body fat percentage is important.....
You might want to get an even clearer picture of body fat here .
Measuring Body Fat Percentage
Body fat percentage, experts say, is more accurate in assessing fat than weight as the latter is simply the grand total of the muscle, fat, bones, organs, body fluids and connective tissue.
It's the amount of body fat expressed as a percentage of total body weight. If your total body weight is 120 pounds and you've 24 pounds of fat, your body fat percentage is 20%.
The higher the percentage above average levels, the higher your health risk of having high blood pressure, diabetes, heart disease, osteoarthritis and certain cancers.
A body fat test cum body fat calculation will "separate" the fat from everything else.
A long time ago, when I started my weight loss program, I didn't give thought to calculate body fat percentage or the amount of fat I need to lose. No wonder I was going nowhere in the weight loss compartment!
That was then. Now, I get "smarter". I take body fat test to know how my body fat would fare, to get me going in the right direction about how much fat I would have to lose, in the battle against bulges.
For us ladies, the body percentage becomes an in-thing even!
So, What's a Good Body Fat Percentage?
Experts consider the range of 20%-35% as healthy for physically active women, and though calculating body fat percentage is darn helpful when you're trying to lose weight, it nonetheless has little bearing on whether or not you're fit or "athletic".
Sure, with a body fat percentage in the low 30s, you'll look fatter and less defined than you do in the low 20s.
But that doesn't mean you're less healthy than say, your friend, who're at the lower end of the range, as long as you exercise regularly and eat a well-balanced, healthy, nutritious diet .
You'll get into trouble only when the body fat percentage surpasses the rate of 35%. At this level, even if you exercise and eat healthily, you'll be facing increased risk for high blood pressure, diabetes and heart disease.
Body fat percentage isn't THE ONLY indicator of your health status. Just because your body fat is in the healthy range, it doesn't mean that your heart and lungs are fit, muscles and bones are strong or cholesterol levels are in check. Good health has many barometers.
However, a body fat test to calculate body fat percentage is useful, as I said, if you want to lose weight. You can set realistic weight goals. I'm sure you've come across people who pick numbers out of thin air - numbers that make no sense given how much lean tissue they've.
Consider this - say at 5 ft 7, you weigh 150 pounds. Then the myth says that you should weigh 100 pounds plus 5 pounds forevery inch of height over 5 feet......... in your case, 135 pounds.
But your body fat calculation showed that, given the amount of muscle you've, 135 pounds isn't realistic for you.
If your body fat percentage is 22%, this means 78% of your weight, 119 pounds, is lean tissue.
If you were to maintain the amount of lean tissue you currently have and drop 18 pounds of fat, you'd weigh 135 pounds, but your body fat percentage would be only 12%!!! That's way, way below the average healthy range.
As you can see, calculate body fat percentage can get kind of "hard"......
How to Calculate Body Fat Percentage?
There are many methods out there to calculate body fat percentage. Let's see. We've got:
- Skin-Fold Calipers
Special calipers measure folds of skin around specific spots on your body. This isn't the most precise method; but it's quite accurate if a trained tester conducts the test.
Accuracy wise, this method assumes that 50% of your body fat is under the skin with the rest located around organs and in muscle tissue.
Genetics, exercise levels, eating habits and obesity are factors that can skew results. Also, there are more than 100 different equations used to compute the numbers, and so accuracy can be off by as much as 6%.
Other factors that can affect the results are:
One, the tester's skill - must be skilled at separating fat from muscle and pinch precisely the right spots. Experienced testers can have difficulty testing if you've lots of excess fat, taut skin or well-developed muscles.
Two, the formula used - different racial groups carry fat in different places.
Three, the tester must use a formula that takes age into consideration. Fat tends to increase with age, so the amount of subcutaneous fat pinched by the calipers in an older individual might not accurately reflect her total body fat.
You can test this at a gym, university or nutritionist's clinic. You can purchase calipers online and do the test yourself but if you aren't trained to use them, the results can run wildly inaccurate.
The cost: professional testing $25 - $50. Do it yourself: free, but you got to buy the calipers, which cost about $25.
Thinking of going by this method to calculate body fat percentage?
- Home Bathroom Scales That Measure or Calculate Body Fat Percentage
Nowadays, you can buy home bathroom scales that measure body fat. Input your age, gender, height and activity level, step onto the scale barefoot, and a low level electrical current, carried by water, travels through your body.
The scales measure where water is NOT located (This is because fat doesn't store water, muscle does) so good hydration is a must for accuracy.
Personally, I think the Tanita and the Homedics/Taylor scales are quite good to use at home to carry out body fat test to calculate body fat percentage.
Tanita scales cost about $120, Homedics/Taylor costs about $80.
- Bioelectrical Impedance
You can calculate body fat percentage vide a full-body, lower body and upper body fat test.
In full-body impedance, a signal travels from an electrode on your foot to an electrode on your hand. The faster the signal, the more muscular you're.
This is because water conducts electricity, and muscle is 70% water and as fat contains virtually no water, so it impedes the signal.
In lower body testing, you step on a Tanita scale, a signal will travel through your lower body from one foot to theother.
In upper body testing, you use a hand-held device such as the Omron Body Logic or American Weights. When you hand-hold the device, the signal shoots through your upper body from hand to hand.
In ideal situation, the margin of error for full-body impedance is about 4% and may be 1 percentage point more for the other 2.
However, all impedance gadgets are sensitive to hydration status. So, if you're dehydrated, the test will over-estimate your body fat by as much as 3 percentage points.
This method is also sensitive to food intake, skin temperature and menstrual cycle.
To get better results, do the test first thing in the morning, before you eat or exercise but after drinking water. Don't test during menstruation because you may have cycle-related water retention.
You can do this test at health clubs and hospital health fairs.
The cost: professional testing $50 - $75, Tanita scale $120, the hand device Omron Body Logic $60 -$75
- DEXA (Dual Energy X-Ray Absorptiometry)
Use this method to calculate body fat percentage, is cool....
A very low dose of 2 different X-ray energies scans your body. DEXA calculates not just your body fat percentage but also thelocation of your fat.
This is valid as knowing where exactly the fat is helps you to know your health risk (e.g. you'll have higher health risk if your fat is mostly stored in the belly, compared to if fat is stored in the hips and thighs).
Accuracy of DEXA? It records a margin of error of 2-3 percentage points.
You can test DEXA at hospitals and at some doctors' clinics.
- underwater Weighing
Whoa! A "cooling magic" to calculate body fat percentage.....
You sit on a scale in a tank of water, blowing out as much air as possible, dunk underwater, then expel some more air.
Your weight underwater is used to calculate your body density. Fat is less dense than water, whereas muscle is denser so the more fat you've, the more your body floats when dunked under water.
It has a margin of error of 2-3%, though it may slightly underestimate your fat content if you've dense bones or are dehydrated. Also, it'll overestimate your fat if you fail to blow out all the air.
You can get this tested at some universities - try call their exercise physiology departments.
- Body Mass Index(BMI)
BMI quantifies your obesity level and is derived from a ratio equation of height squared divided by weight.
Only your height and weight are used and no indication of actual fatness or leanness is ascertained. But it's useful guide to gauge whether you're obese or not.
Ah, the cheapest way to calculate body fat percentage.....
I reckon the most accurate methods used to calculate body fat percentage are DEXA and underwater weighing. However, they aren't easily available.
The easiest and most convenient method would be the skin-fold calipers and the bio electrical impedance gadgets. However, they've a greater margins of error.
Really, I would think, the choice comes down to personal preference. The thing is to find a method you like and if possible, get measured by the same person and the same instrument.
Whichever method you choose, don't get tested more often than every 2 months, as body fat testing and body fat calculation aren't sensitive to small changes.
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