Many people on weight control plans rely on the bathroom scale to measure their progress. But this isn't the only option. Lots of different techniques -- some simple, others complicated -- can be used to track your fitness and weight loss goals. Critics of the bathroom scale note that it's important to track your body composition, including body fat percentage, rather than just your weight. Here are some examples of tests that go beyond the bathroom scale:
- Body mass index, or BMI, is a calculation based on your height and weight. The calculation helps your doctor tell if you may be at risk for health problems because of your weight. It tends to be less accurate in people who are very muscular or very short. One disadvantage is that the BMI doesn't provide any information about body fat.
- Similarly, waist circumference is another simple test you can do right away. Measure around your waist at the level of the belly button in inches. If you're a man with a measurement higher than 40, or a woman with a result higher than 35, you are at increased risk for certain health problems like heart disease and stroke. Of course, like the BMI, this doesn't tell anything about your body composition or fat percentage.
- Skinfold calipers have been available for years to measure body fat. A measuring device is used to “pinch” the skin and tissues at different places on the body, estimating body fat percentage. Results of this test can vary widely and depend on the quality of the calipers and the skill and experience of the person performing the test.
- Body fat scales are available for home use. These work by sending a small, harmless electrical current through the body to detect fat and lean tissue, providing a reading of your body fat percentage. Because these measurements can change according to the time of day and fluid and food intake, the results are most accurate if you can take the measurements at the same time each day. The devices overall likely vary in accuracy, but they can be good for tracking changes over time.
- DEXA, or dual-energy X-ray absorptiometry, is a test similar to that used to measure bone density. It has been used to identify specific fat deposits and to determine body fat percentage. DEXA scanning is an emerging technology in the fitness area and is typically offered by medical offices, although some experts feel it may be more widely available soon. It is more accurate than home body fat scales.
- Hydrodensitometry testing involves immersion in a water tank to calculate your body fat and density based on the amount of displaced water. This technique is understandably cumbersome and is also not widely available. Some universities use this technique with athletes and may allow others to use it for a fee.
- The Bod Pod operates on a similar principle, but you don't have to be submersed in a tank. This is a new device based on air displacement plethysmography (ADP) that consists of a chamber in which air displacement is measured. Still being refined, this method can provide a good measurement of body fat percentage without the disadvantage of having to be submersed in water. Hydration level can also affect the results of this test, and the individual being measured needs to sit very still and control breathing during the measurement process. Like underwater measurements, this method is often used by university athletics departments.
Medically reviewed by Avrom Simon, MD; Board Certified Preventative Medicine with Subspecialty in Occupational Medicine
Hamdy, Osama, et al. "Obesity." Medscape. 26 Aug 2013.