What is Body Fat Percentage?
Body fat percentage is the percent of your total body weight that is comprised of fat.
If you are trying to lose weight by reducing fat, then, all else held equal, you are trying to reduce your body fat percentage. In the same manner, if you are attempting to build muscle, you also want to decrease your body fat percentage to show off the fruits of the time you spent in the gym. You do this through a combination of increasing your lean body mass and the amount of fat that you burn.
The problem with measuring percentage of body fat, however, is that it is difficult to estimate exactly with a formula.
It is less important, however, that the measure be absolutely correct than it is that the measure be directionally correct. That is, based on changes in your body’s composition, does the metric accurately measure the direction and approximate size of that change.
Recall the scale. Even if we are meeting our goal of reducing body fat, it may show an increase in weight - it will not be directionally correct.
What are the Methods for Measuring Body Fat Percentage?
Water Displacement Method
The most accurate way to measure body fat percentage is with the water displacement method. This is done by completely submerging you in a tank of water and measuring the overall displacement. Because fat is less dense than muscle and bones, it is relatively straight forward to estimate percentage of body fat. However, this is often expensive and time consuming to perform, and cannot be performed in the home.
Skin Fold Calipers
Skin fold calipers are readily available in the market place and can be used to provide an estimate of body fat percentage. This method is often used when you visit a fitness center, but can be easily used at home.
You use the calipers to measure a pinch of the skin at particular areas around the body. This provides us with an estimate of the thickness of subcutaneous (below the skin) fat.
These measures are then placed in a formula to derive the percentage of body fat. You will get some variation in the results depending on who is administering the test. However, if the same person takes the measure in the same way each time, then your results should be directionally relevant.
Bioelectrical Impedance Analysis, or BIA
The next method is by using Bioelectrical Impedance Analysis, or BIA. BIA is used by some fitness centers, but less accurate (but directionally relevant) methods are available on many home scales at an affordable price. Generally speaking, in the home method, a person stands with bare feet on two conductors located on the top of the scale. A small electrical charge is sent through the body. Since the amount of electrical resistance is different between fat, muscle and bone, the amount of resistance between the two conductors provides an estimate of body fat percentage.
Formulas
Finally, there are several formulaic methods that are readily available. The United States Naval method is perhaps the most accurate and is directionally correct. This method has a slight variation for men and women, and takes into account neck girth, height and weight for both men and women. The formula for women also includes hip circumference.
It is important to remember that this method uses the metric system. To use the formulas, you must first divide your height, and waist, neck, and hip circumference in inches by 0.3937 to convert these measures to centimeters.
What are the Formulas to Measure Body Fat Percentage?
There are two formulas - one for men and one for women - to measure body fat percentage.The formula for men is:
The formula for women is:
where "waist", "neck", and "hip" are all circumferences (distance around) in centimeters.
What are the Guidelines for Body Fat Percentage?
The American Council on Exercise provides the following guidelines on the percentage of body fat for men and women:
| Classification | Women (% fat) | Men (% fat) |
| Essential Fat | 10 to 12% | 2 to 4% |
| Athletes | 14 to 20% | 6 to 13% |
| Fitness | 21 to 24% | 14 to 17% |
| Acceptable | 25 to 31% | 18 to 25% |
| Obese | 32% + | 25% + |
However, if you goal is to see your six pack, your body fat percentage needs to be less than 10% for men and 14% for women to begin to see your abdominal muscles.
At the end of the day, it is clear that your percentage of body fat is the best way to measure your "weight loss" success!
Calorie Calculator: Calorie Intake Calculator
The second part of the Middle Management™ Simple Calorie Calculator is the calorie intake calculator. The calorie intake calculator estimates how many calories you should eat per day to lose 1 pound of fat per week, 1.5 pounds of fat per week, and 2 pounds of fat per week.
To do this, the calorie intake calculator uses the fact that it takes a calorie deficit of 3,500 calories to burn 1 pound of fat. So, to determine how many calories you need to eat per day to burn 1 pound of fat per week, divide 3,500 calories by 7 days. The result is a 500 calorie deficit per day to lose 1 pound of fat per week.
Using the same logic, to lose 2 pounds of fat per week, you should eat up to 1,000 calories less per day than you burn.
The calorie intake calculator uses the result from the daily calories burned calculator to estimate how many calories you need per day to burn fat.