These tell you nothing more than your relationship with gravity. Even if you achieve the nirvana of gaining muscle while simultaneously losing fat, your bathroom scales probably won’t budge. Remember, nobody wants to lose weight – what everybody really wants to lose is fat, and scales are clueless about fat.
Calipers rely completely on the person doing the measurements and which formula is applied. For any chance of a reasonable result, caliper readings must be done by a skilled technician who needs to be meticulous in technique. A measurement taken just one or two centimetres away from a defined site can lead to wildly different results. What’s more, calipers only measure subcutaneous fat, which lies just under the skin’s surface. They are completely blind to the visceral fat that surrounds your internal organs and which has been linked to heart disease, diabetes and even cancer.
Sometimes known as the ‘Dunk Tank’ is time-consuming, uncomfortable and relies on an estimate of the amount of air in your lungs and digestive tract. Underwater weighing also ignores the fact that the density of fat-free mass changes with weight and ethnicity.
This method uses air displacement plethysmography (ADP) and is very poor at tracking changes over time. It is adversely affected by many variables (including clothing, temperature and moisture) and typically overestimates body fat.
These devices and ‘fat scales’ are notoriously unreliable and typically underestimate body fat. The gadgets are adversely affected by hydration levels and most only work on the upper or lower half of the body. Bio-impedance is often no more accurate a measure of body composition than the discredited body mass index (BMI). DEXA does not rely on the skills of the operator and is not affected by human error, bad calibration or what you had for breakfast. What’s more, only DEXA shows you (visually and with hard data) the distribution of fat in all sub-regions of the body – arms, legs and trunk