The most popular and widely used methods of measuring your weight for health reasons is BMI, the Body Mass Index. it’s easy enough to find an online calculator and categorise yourself into the underweight, ideal, overweight and obese groups, but just how accurate is this measurement? Without taking muscle and fat ratios into account, the BMI can produce wildly inaccurate results, with some world-class athletes and fitness enthusiasts being classed as obese because of the weight of their muscles. It’s an excellent initial indicator of your health but tells us nothing of body composition.
So what are the most accurate body fat measurement tool options available?
The first and least expensive option is to use a skinfold calliper.This involves a trained professional or experienced user taking repeat measurements from up to 12 various sites from one side of the body and then subjecting the results to formulas and comparing them to normative charts to determine your body fat percentage. You can carry out measurements yourself, but you are limited to testing sites by your reach – you just can’t measure skinfold on your back.
The upside to the calipers is that they’re very easy to read and very affordable, as well as easily repeatable for monitoring of fitness progress over time. They are accurate and dependable when a skilled user is taking the measurements. The downside is that if you are over 15kg or so overweight, the results can be very misleading as the width to which the calipers can open is limited and some folds may not fit. If the folds are not in precisely the same position throughout testing on a different occasion, results may vary and compromise the accuracy of the calipers.
The second option, with a slightly higher price tag, is BioImpedance Analysis (BIA).
BIA Scales are widely available and measures the opposition to the flow of a certain and small electrical current through the body. Muscles contain a lot of water, making them brilliant conductors, whereas fat has much lower water content, and, therefore, are less efficient conductors of electricity. By measuring the impedance within the body along with height and weight data, the BIA scales can estimate fat-free body mass and your body fat percentage.
These measurements couldn’t be easier to obtain, as all you have to do is stand on the scales and wait, as with simple bathroom scales. They are relatively inexpensive, with BIA Body Fat Analysers from £30 to more advanced scales in the region of £12,000 +.
However, they can be easily influenced by hydration levels which can lower the overall accuracy of the method. This can be combated by taking notes of the amount of water you’ve consumed before taking the test and taking that into account when tracking your progress. It has also been found that individuals with very low body fat percentages have been presented with inaccurate results.
Another option is Hydrostatic Weighing, widely regarded as one of the most accurate measurement of body composition. Considered by some as the ‘Gold Standard’ of body fat reading and involves an exciting sounding specialised tank of water.
This accuracy is achieved by emptying your lungs of all air while submerged the weighing taking place underwater. Bone and lean mass are heavier in water, so if you’re heavier, you have low body fat percentage. Fat, on the other hand, becomes lighter in water – so if you weigh-in lighter you’ll have a higher body fat percentage.
While the superb level of accuracy may be worth finding out, it’s incredibly impractical for an everyday fitness enthusiast. It’s not something you can do at home or in a standard gym and is somewhat expensive. It’s also not suitable for repeat testing unless your budget for fitness monitoring is prioritised over food. If you do decide to take the plunge, you should set aside a good hour to complete the analysis.
The next option is a DEXA Scan , this is a little impractical and was originally used to check for osteoporosis in older individuals, this incredibly accurate technology has now been utilised in the sports science world but is still only available in some hospitals and laboratory settings.
This takes about 10-20 minutes of your time and nearly £150 of your hard earned cash each time you go for a test. Dual Energy X-ray Absorptiometry breakdowns the body compositions into mineral mass, fat mass and fat-free mass, offering an extra dimension over Hydrostatic weighing.
While it’s a fantastic method to find out accurate information about your body composition, it’s not a practical or repeatable technique, and therefore, might not be a worthwhile investment.
The final choice is Ultrasound Scanning . This minimally invasive scanning technique isn’t just for pregnant women; it can also provide you with body fat percentage information as well as your BMI, BMR (Basal Metabolic Rate), lean body mass, relative disease risk and point-specific thickness measurements. And it doesn’t have to be carried out in a hospital or laboratory, with handheld personal Bodymetrix scanners readily available for you to scan yourself at home. Just connect to your PC with the supplied USB cable and monitor your results as you progress.
This method is fast and accurate, with reliable results provided in seconds that are unaffected by hydration levels, how much air is in your lungs, caffeine or calorie intake or time of day. You can repeat the measurements easily and frequently without the need for specialised training required for callipers.
In reality, every method we have discussed is an estimation, the only real way to find out your body fat percentage with absolute certainty is to undergo an autopsy, but clearly this isn’t a preferable method of measuring your body composition. Because (hopefully) you aren’t ready for that level of body exploration, the accuracy of results available to you is always going to be compromised a little.
Because of this, convenience and cost are the next important factors, hydrostatic weighing and DEXA have great accuracy but are often not a practical option, skinfold calipers can be great if you are experienced in taking measurements and ensure high levels of accuracy and BIA scales and devices are an excellent option if you can keep variables such as hydration, time of day as consistent as possible to avoid some of the measurement errors. Ultrasound technology is a fantastic option for regular non-invasive monitoring, its portable, accurate, eliminates skin pinching and can also measure muscle too.
Take a look at all methods, investigate further and decide which body fat measurement tool that works best for you.