Your Ideal Weight: BMI vs BF%

            If you’re trying to reach a healthy weight, how do you determine what your weight should be? There are some measurements used by doctors and physical fitness experts that might help. The two most common are Body Mass Index (BMI) and Body Fat Percentage (BF%).  These two measurements are very different, though used for essentially the same purposes.

            BMI is more easily calculated, in that it only requires the height and weight of a person and from there can be entered into and equation [BMI = weight in kg / (height in m x height in m)], an online calculator, or by looking at a BMI chart often found in a doctors office. However, because BMI is such a simple measure it doesn’t take certain factors such as body type and gender into account. Thus, for some people (i.e. muscular male) BMI may not be a good measurement.

            Body Fat Percentage is quickly becoming the more preferred method for accurately determining an ideal weight because it’s measurement methods take more than just height and weight into account, and focus specifically on body fat and not just mass.  BF% can be measured several different ways. The most accurate ways of BF% measurement involve either submersing yourself into a special tub of water (hydrostatic weighing) that can cost a good chunk of change to use or getting a particular kind of X-ray scan (Duel Energy X-ray Absorptiometry) that is even pricier. Luckily there are some other fairly accurate methods that can be used at home:

  1.  Bioelectric Impedance Analysis: This sounds complicated but all you need to do is to stand on a special scale like this one

 and let it do the work for you. They also make hand held devices that some gyms keep on hand.

  2.  Anthropometric: Another fancy word that just means measuring body circumference. As part of our fitness competition my brother and I used the US Navy’s BF% calculator. We found it more accurate than some of the other online BF% calculators.

  3. Skin Fold Caliper: This requires a special instrument like many of the other methods, though not so pricey. If done correctly it is pretty accurate (though possibly not for individuals more than 40lbs overweight).

With your calculations from these measurement you can then use a BF% chart that will help you determine what BF% is right for you.

Whether you use BMI or BF%, hopefully this information helps you determine a healthy goal weight. But of course, your own experience with your body at different weights, and advice from your doctor will be important things to also take into consideration. Your ideal weight should be one that will keep you feeling great and help your body endure with ease your normal daily activities.

Other informative resources on this topic:

http://www.builtlean.com/2010/07/13/5-ways-to-measure-body-fat-percentage/

http://en.wikipedia.org/wiki/Body_mass_index