Measuring Fat Levels
Weight-loss generally involves shedding pounds of fat. And so it makes sense that dieters would want to know what their fat level is. However, athletes and those not dieting should be interested as this measure provides some insight in to your overall health.
Getting on the bathroom scale is something we've all done. We use the number we get to see how fat we are. It's simple, quick, can be done everyday, and only takes 5 seconds. The problem is that your weight is a very poor indication of how much body fat you have. There is no differentiation between muscle weight and fat weight, and to further complicate matters, muscle is heavier than fat. So, someone who is involved in a muscle building program is likely to gain weight as measured by a scale, but this is a good thing. Remember, we want to measure body fat and not just weight. Dehydration or water retention is another factor that will affect the dial on the scale, especially for women as their weight changes throughout the month. So it's all relative.
Body Mass Index
Body Mass Index (BMI) is simply a measure of your weight relative to your height. It assumes that everyone should be within a certain weight range based on their height. For the average person this measure is fairly accurate. However, this measurement does not take into account someone who may have more muscle mass, e.g. body builders and athletes.
Waist to Hip Ratio
Another measure is the waist to hip ratio. Taking a measurement of your hip circumference compared to your waist circumference will give you this ratio. If your waist is too large it means you are carrying too much body fat. This method is easy and fairly accurate, however, not everyone has the same body type and not everyone carries fat in the same areas of the body.
Electrical impedance measures your body fat percentage by passing a slight electrical current through your body. The theory is that fat is not conductive, while other tissue is. Based on the measurement and some formulas the machine calculates your body fat percentage. This method is quite accurate. However, you need special equipment and there is an expense that comes with such equipment. This method is usually done by physiologists working with athletes or sometimes at upper scale gyms. There are scales on the market that claim to also do this, however, their accuracy is questionable. As with a scale, factors such as dehydration and water retention will alter the results.
The most accurate method is your water weight. Again specialized equipment is required, but the concept is quite simple -- fat floats while muscle sinks. By weighing someone underwater we can determine (with formulas) their body fat percentage. More trouble than it's worth for the average person.
Skin Fold Test
Skin fold tests are what gyms use most often with their clientele. It is fairly accurate, but depending on the training of the tester, as well as the age, skin type, hydration of the testee, the results may vary. The procedure involves pinching the skin at certain body sites and measuring the thickness of the pinch. Using a couple of formulas will result in a body fat percentage.
On a day-to-day basis, your clothes are good measures of gaining weight. If your clothes feel tighter it's not that they are shrinking but rather it's that you're gaining fat. If your clothes feel looser then you are losing fat. So, keep a pair of pants around for measuring your fat levels. Put them on every week and see how they feel. The problem with this method is that you need to be brutally honest with yourself.