What Are Body Fat Scales?

Carrying around excess body fat not only affects your physical appearance, it also puts you at higher risk for heart disease, type two diabetes and even some forms of cancer. The Centers for Disease Control and Prevention estimates that as many as 72 million Americans could be considered overweight with a body mass index score of greater than 30. Body fat scales can help you estimate and track this measure of body fat.

How They Work

Body fat scales typically work through bioelectrical impedance. This means that as you stand on the scale, an electrical current is sent through your body and back into the scale. The scale then measures how quickly the current reaches back to the scale. The scale interprets the results based on how fast electrical current passes through fat versus water and muscle. The current takes longer to move through fat, so a relatively slow result translates into a higher body fat percentage. A faster current means your body has more muscle, resulting in a smaller body fat percentage.

Benefits

A body fat scale can help you estimate your overall body fat percentage, which can help you determine how successful your weight loss efforts are, as well as whether you are losing water weight or actual fat. Use the results to change your diet, aerobic exercise and strength training routines until you find a mixture of calorie intake and calorie burning that reduces not only your weight, but also your percentage of body fat.

Disadvantages

Body fat scales vary in accuracy. Because these scales use bioelectrical impedance to determine your body fat percentage, certain factors can alter the results. For example, bioelectrical impedance is affected by how much water you drinkm so dehydration can alter the results. Other factors that can alter the results of a body fat scale include your body temperature, the temperature of the air surrounding your body and whether you have recently exercised before getting on the scale.

Alternatives

Although a body fat scale can give you an estimate of your body fat percentage, other methods provide more accurate results. For example, body calipers measure body fat on different areas of the body, which are inputted into mathematical equations to provide a body fat estimate. A more accurate method is dual energy x-ray absorptiometry, which is used to provide an x-ray image of your bone, muscle and fat ratios. Air displacement plethysmography is used to measure body fat by placing you in an egg-shaped chamber that uses air displacement to measure your volume, weight and body density. Finally, if facilities are available, you can use hydrodensitometry, or under-water weighing to determine an accurate body fat percentage.