So, you want to lose weight and you know that to do so, you should keep track of fat loss. You ask yourself, "Should I use the BMI or a body fat scale?" Good question. And the answer is… It depends. If you know the limitations of both of these 'measurements' you'll be better prepared to make one or the other work for you.
The first and most obvious limiting factor with a body fat scale is: If you do not already own one, you'll have to buy it. The BMI is just a table—which is viewable below. A body fat scale uses bioelectrical impedance to measure your fat percentage. What this means is, the scale sends an electrical current though your body. The problem with this method is that with severely overweight people, the accuracy is diminished. In my case—I bought one—the reading was completely off the scale, so to speak.
Also, these home body fat scales are not very useful in monitoring changes in body fat for people on a diet—those who are losing weight. If you are only moderately overweight, however, one of these scales could work for you. At least you can take comparative readings—noting the difference from one weigh-in to the next. This will be more accurate for measuring small increments of fat loss than the BMI, which I'll now discuss.
The Body Mass Index, created by (or for) the National Institutes of Health (NIH), is used by doctors in the U.S. to evaluate the probability of health risks in overweight—and underweight—people. While a BMI number can be a good indicator of a person's current health risk category, it is not very accurate for two groups of people:
And, more importantly—for dieters anyway—you'd have to drop 5 to 8 pounds (2 to 4 kilos) to get to the next lower BMI number in the table. This is not very practical for persons wanting to keep track of fat loss on a weekly basis. For the reasons mentioned here, I am choosing a third option for measuring body fat percentage. Yes, there are other methods for measuring total body fat, and... fat as a percentage of your weight.
What I'm using on my weight loss diet (and exercise) plan, is the body fat formula. While this method for measuring body fat is, also, not entirely accurate, at least it doesn't put you into a category like, Obese or Extreme Obesity. And, you can watch the number go down as you lose weight and take inches off of your midsection.
v = (Body weight x 0.732) + 8.987
w = Wrist measurement (fullest point) / 3.140
x = Waist measurement (at belly button) x 0.157
y = Hip measurement (fullest point) x 0.249
z = Forearm measurement (fullest point) x 0.434
Lean Body Mass = v + w - x - y + z
Body Fat Weight = Body weight - Lean Body Mass
Body Fat Percentage = (Body Fat Weight x 100) / Body weight
x = (Body weight x 1.082) + 94.42
y = Waist measurement (at belly button) x 4.15
Lean Body Mass = x - y
Body Fat Weight = Body weight - Lean Body Mass
Body Fat Percentage = (Body Fat Weight x 100) / Body weight
NOTE: This is only the left section of the table. To view the entire table, click on the image. A PDF will open in your browser and you can choose…
…in that window to save it to your computer for later viewing.
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