When it comes to tracking weight loss, most of us rely on the scale to tell us whether we've lost or gained weight.
Standard scales can tell you a total weight and measures everything including muscle, fat, bones, and what you ate or drank that day. It doesn't tell you how much lean muscle you have. It does not take into account any food in your stomach or any water weight you may be carrying.
Additionally height-weight charts do not take into consideration athletes and bodybuilders physiques. According to current height to weight charts athletes and bodybuilders can be classified as over-weight when in fact they are not. Why?
Understanding Body Fat
Total body fat percentage consists of essential fat and storage fat. Essential fat is that amount necessary for maintenance of life and reproductive functions. The percentage for women is greater than that for men, due to the demands of childbearing and other hormonal functions.
Storage fat consists of fat accumulation in adipose tissue, part of which protects internal organs in the chest and abdomen.
The Importance Of Body Composition
When trying to build a better physique it is important to understand body composition and to be able to track change in body composition. Body composition is the ratio of lean body mass to fat body mass.
Too much fat can lead to health problems like heart disease, Type 2 diabetes, high cholesterol, and many other serious conditions. By keeping your body fat within a reasonable level, you'll be healthier, feel better, increase your life expectancy, reduce your risk of certain conditions and of course, look slimmer as well.
Methods For Measuring Body Fat
Calipers (The Pinch Test)
How It Is Done
- This method uses calipers to measure skinfold thickness at several areas of your body. An expert pinches your skin at several standardized points on the body to determine the subcutaneous fat layer. The results are then plugged into a formula to determine your body fat. Some formulas require as few as three measurements, others as many as seven.
- The accuracy of these estimates is more dependent on a person's unique body fat distribution than on the number of sites measured. The result is based on the idea that thickness of fat under the skin reflects total body fat.
- This is one of the more accessible ways to check body fat and is generally painless.
- You can get tested at most health clubs and universities for little or no cost.
- It depends on the skill of the tester at separating your fat from your muscle and finding the right spots to pinch.
- Results varying when done by different people.
- The results can also be skewed if you're older (since fat moves inward with age).
- Results can vary for more, muscular individuals, which tend to have more fat associated with the muscle.
- The formulas are based on white subjects, therefore if you are not white the numbers calculated can be skewed.
- Additionally it is of utmost importance to test in a precise location with a fixed pressure.
Height And Circumference Methods
How It Is Done
- There are formulas for estimating body fat percentage from an individual's weight and girth measurements.
- For example, both the U.S. Navy, U.S. Marine Corps and U.S. Army compare abdomen or waist and hips measurements to neck measurement and height to estimate one's body fat percentage. The measurements are compared to a height/weight chart with age factored in.
- Age is factored in
- Depends on the skill of the tester taking measurements.
- This method poses a particular threat of inaccuracy because one can hold one's stomach in more if needed to pass the requirements, and/or flare the neck out and make it bigger resulting in a lower body fat percentage.
- Due to different body compositions, those with larger necks have an advantage over those with smaller necks.
How It Is Done
- A beam of infra-red light is transmitted through the skin of the biceps. The light is reflected from the underlying muscle, and absorbed by the fat.
- This method CAN be accurate (2-3% margin of error).
- Not all facilities perform this test.
DXA (Formerly DEXA, Or Dual Energy X-Ray Absorptiometry)
How It Is Done
- The DEXA test uses a whole body scanner and two different low-dose x-rays to read bone mass and soft tissue mass.
- Quick. It takes about 10-20 minutes to do a body scan.
- It provides a high degree of precision with a 2-3 % margin of error.
- It measures bone density, body fat percentage as well as where most of your fat is.
- The DEXA Test is considered a gold standard for measuring body fat and bone density.
- The cost is usually about $100.
- Not offered by many places.
Bioelectrical Impedance Analysis (BIA)
How It Is Done
- The general principle behind the Bioelectrical impedance analysis (BIA) method is you take two conductors which are attached to a person's body and sent a small electrical current through the body. The resistance between the conductors will provide a measure of body fat, since the resistance to electricity varies between adipose, muscular and skeletal tissue.
- Either using a handheld scale or standing on a BIA scale, a signal passes either from hand to hand or foot to foot.
- Fat-free mass (muscles) is a good conductor as it contains a large amount of water (approximately 73%) and electrolytes, unlike fat which is anhydrous and a poor conductor of electrical current. The faster the signal travels, the more muscle you have.
- This is one of the quickest methods of testing body fat using a BIA scale.
- This method CAN be accurate (4% margin of error).
- Bioelectrical impedance analysis is available in a laboratory, or for home use in the form of body fat scales and hand held body fat analyzers.
- Factors that affect the accuracy and precision of this method include instrumentation, subject factors, technician skill, and the prediction equation formulated to estimate the Fat Free Mass.
- Gender bias. Because men and women store fat differently around the abdomen and thigh region, the results can be less accurate as a measure of total body fat percentage.
- Another variable that can effect the amount of body fat this test measures is the amount of liquid an individual has consumed before the test. As electricity travels more easily through water, a person who has consumed a large amount of water before the test will measure as a lower body fat percentage. Less water will increase the percentage of body fat.
- Results are effected by hydration, food intake and skin temperature. If you're dehydrated, you're body fat percentage will read higher than it is.
- Test can be skewed if taken at different times of the day. For a more accurate result test at the same time of day, preferably first thing in the morning before breakfast, before training, and after hydrating.
Prior to the adoption of DXA, the most accurate method of estimating body fat percentage was to measure that person's average density (total mass divided by total volume) and apply a formula to convert that to body fat percentage.
Since fat tissue has a lower density than muscles and bones, it is possible to estimate the fat content. The body fat percentage is commonly calculated from one of two formulas:
- Brozek formula: BF = (4.57/? - 4.142) ?- 100
- Siri formula is: BF = (4.95/? - 4.50) ?- 100
In these formulas, ? is the body density in kg/L. For a more accurate measurement, the amount of bone tissue must be estimated with a separate procedure. In either case, the body density must be measured with a high accuracy.
How It Is Done
- You sit on a scale inside a tank of water and blow out as much air as you can.
- You are dunked underwater, where you blow out even more air.
- Since fat is lighter than water, the more fat you have, the more you'll float.
- The scale also measures underwater weight to figure out body density.
- The margin of error is around 2-3%, but the accuracy depends on the amount of air you expel.
- This method gives highly reproducible results.
- The test can be uncomfortable (water can be cold), some people are afraid to be dunked, and some people can have a difficult time expelling all the air to get an accurate test.
- This estimate can be distorted by the fact that muscles and bones have different densities: for a person with a more-than-average amount of bone tissue, the estimate will be too low.
- The margin of error depends on the amount of air you expel.
- Most gyms do not offer the test.
- The test can cost upwards of $50.
- Taker longer than the other methods to complete the test.
- You need a change of clothes (bathing suit)
Body Mass Index (BMI) Calculators
How It Is Done
- You can figure out your Body Mass Index using a formula or with an online calculator, such as the one offered for free at www.YourbestHealthPortal.com , or at www.MuscleMagFitness.com.
- The BMI calculator uses a formula that takes into account your weight and height, and then compares the number calculated to a BMI chart.
What It Means
- A BMI less than 18.5 indicates underweight
- A BMI of 25 - 30 is considered overweight
- A BMI of over 30 is considered obese
- Cost (free)
- Time (quick)
- It doesn't give you a body fat percentage, but indicates whether you're obese or overweight. For example, if your BMI is 18, that doesn't mean your body fat is 18%.
- This calculation isn't as accurate, as it doesn't take into account age or sex. It also does not take into account muscle. Meaning someone that is a bodybuilder can be classified as obese based upon the current formulas.
Body Fat Level Trending
The average body fat percent in the United States and Europe is increasing, leading to an increase in many weight related conditions.
What Body Fat Levels Are Considered Normal?
- Essential fat is 2-5% in men, and 10-13% in women. Therefore anything below these levels is unhealthy.
- To be more gender specific, the recommended amount for women is typically 20-21%, while the recommended amount for men is 8-14%.
- 15-20% is considered a healthy range for athletes, 21-24% is healthy for fitness, 25-31% is considered an "acceptable" range and anything above 32% is considered obese.
- The leanest athletes typically compete at levels of about 5-8% for men, and approximately 10-15% for women. Some bodybuilders will often compete at ranges even lower than these levels but will not sustain these levels off-season, since it is below the essential values and unhealthy to remain at these levels for any extended period of time.
Changing Body Composition
To increase or decrease your percent of body fat you need to create the right balance between the calories in and calories out. The best way to do this is to decrease daily calories by about 500 and increase your exercise. Aerobic exercise along with strength training is ideal.
By increasing your muscle mass through resistance training you also increase your basal metabolic rate and burn more calories throughout the day as a result.
As you can see, there are many ways to measure body fat. Some ways are more accurate than others. Although accuracy is important, if the test are done correctly they all can measure body fat within 2-5%. What is most important is reproducibility (meaning that when you measure and remeasure your body fat, that you are using a similar test so you can track your progress.
By understanding your body composition and then establishing a sound healthy diet and increasing the amount of exercise routinely you can have a positive effect on your body composition, thereby decreasing body fat, increasing lean muscle and increasing your quality of life.