Accuracy of body fat analyzers?
Hi, I'm looking for some advice. I have two body fat analyzers, one that you hold in your hands and it sends an electric pulse, and another that you stand on, which does the same. I've noticed that when I use the handheld one first thing in the morning, after having a quick drink, it reports my bodyfat as 12%, but when I do it again a few hours after breakfast, its gone up to 14%. Why is this and which do you think is more accurate? On the other hand, the scale one is around 15% throughout the day, which seems a bit high. I'm male, 5'8" 159lbs with 31" waiste, if that helps.
Public Comments
- In my experience neither are very accurate, the best way is to get a qualified professional at the gym to do it with callipers once a month. The machine thing that you hold varied by more than 5% with me within 2 minutes!
- I have a stand on one and I was getting variable results throughout the day so its not surprising if 2 machines also do the same. By their very nature I dont think they can be entirely accurate. Either that or bodily fluids affect the readings which they probably do. I think they are a good rough guide to fat analysis but to take daily readings is probably pointless. There wont be significant changes over such a short period of time and eventually you feel like giving up monitoring altogether. If you are exercising and dieting and working hard to reduce fat then I would suggest taking one reading from each machine once a week. Same time, before a drink. Take the average and monitor your progress.
- The body fat analsyers are called bioelectrical impedence analysers. They measure the resistance provided by fat mass and the reactance by muscle. i.e. the electric pulse cannot travel throuh fat as it does not contain water but it can travel through muscle as this contains water and therefore conducts the current. These machines have maaaany limitations including their design (no way to get around the physics), hydration status and the mathematical equations it uses to tell you your fat mass, just to name a few. Unfortunatly there is no perfect ways to measure body fat (well, there is one way it is like a cat scan and is called DXA but it is really only used in scientific studies if your lucky enough to get ahold of it). The difference between the two body fat analysers you have are the body regions they are measuring. The hand held ones measure the fat mass of the upper body. One side send the electric signal the other collects it therefore the legs will not contribute as much (I have used this type and it said my fat mass was 30% but I am a girl and it was measuring the bust area, the stand up one records it as 20%). The differences between the two readings of the hand held would related to fluid distribution changes throughout the day and internal changes in the machine itself. Personally, I would be more inclined to use the one you stand one. Yes, 15% does sound a little high for a male with your dimentions. Don't take it literally, realise that it really is an estimation. Skin folds, which a previous responded suggested, is another way to measure fat mass and is often better to watch for changes of time. Although whether it is more accurate is questionable as it relies alot on the person conducting the measures, the quality of the calipers, fluid balance, the equation used to obtain the fat percentage and the sites chosen to measure. Try to find someone that is accredited with ISAK to measure your skin fold as many people just say they know how without really having a clue. Hopefully this clears things up and ansers your questions.
