Body fat scalesThe right body fat scales can provide a cost-effective and convenient way of measuring body fat. The right body fat scales are ones which measure from both the hands and feet, rather than from either the feet or hands alone. =How they workThey Work=These Bioelectrical Impedance Analysis (BIA) scales use an imperceptible electrical signal to calculate the amount of water in the bodyand thus estimate body fat. From this Total Body Water (TBW), it is possible BIA compares the electrical resistance of a direct current to an alternating current. The direct current does not penetrate the cell walls whereas the alternating current does. This creates a difference that allows an estimate body fatof extracellular water. ==Two or Four Electrodes==BIA scales either have two electrodes that measure from the feet, or four electrodes that measure from both the hands and the feet. You can see in the image images below the path electricity takes with scales that measure via feetonly compared with when measurements are from the hands and feet. I would not recommend any BIA scales that measure from the feet only. There are also [http://www.amazon.com/Omron-Logic-Monitor-HBF-306C-Silver/dp/B00006WNPU BIA devices that measure from the arms only], but these suffer from similar problems.{| class="wikitable" |- valign="top"|[[File:Human Figure Lower.jpg|none|thumb|300px|The path taken by body fat scales that only measure between the feet.]]By comparison, you can see the path taken when measurements are from the hands and feet. |[[File:Human Figure Full.jpg|none|thumb|300px|The path taken by body fat scales that measure from the hands and feet.]]|}=Recommended scales – Omron HBF-510=Single or Dual Frequency==Having tried several body fat scales I would highly recommend Typically the Omron HBF-510alternating current is around 50 kHz, which retails with dual frequency scales adding in 6.25 kHz for about $60-$65 on [http://goimproved accuracy.fellrnr.com?id=35454X937677&xs=1&url=www.amazon.com%2FOmron-HBF-510W-Composition-Monitor-Scale%2Fdp%2FB001IV61J4 Amazon.com]. The Single frequency scales measure from both generally treat the hands and feet providing reasonable accuracy for relatively low cost.[[File:Omron HBF-510.jpg|none|thumb|200px|The most cost effective body fat scale, the [http://gois a single cylinder with uniform resistance.fellrnr.com?id=35454X937677&xs=1&url=www.amazon.com%2FOmron-HBF-510W-Composition-Monitor-Scale%2Fdp%2FB001IV61J4 Omron HBF-510].]]To use Unfortunately because the scales you simply step on them holding arms and legs are thinner than the handset with your trunk they contributed disproportionate amount of resistance. Typically arms at 90°. After a few seconds these scales will display your and legs are about 5 to 20% of body weight, body fat and other metrics. [[File:Omron HBF-510 correct posture.jpg|none|thumb|200px|The correct posture.]]It's important to get but form about half of the posture just rightoverall resistance, as even small variations in while the position trunk contains 50% of your arms can make a significant change the body mass and contribute only 5 to 10% of the readingoverall resistance.[[File:Omron HBF-510 posture errors.jpg|none|thumb|400px|Posture errors.]] =Worth considering – Tanita BC-601=The Tanita BC-601 is a much more expensive set of body fat Dual frequency scales. In addition to measuring from on the hands and feet, the scales use dual frequencies (see below) for greater accuracy. They also other hand segment the body up into five compartmentscylinders, two for the arms, two to for the legs, and one for the trunk, giving body fat readings for each compartmentmuch higher accuracy. The scales also write the measurements to a flash memory card for direct transfer to computer. Sadly, the scales are not sold directly the US and I imported mine from the UK which was While more expensive and remarkably time-consuming. With shipping I paid 185 GBP ($280) from [http://www.scalesexpress.com/ http://www.scalesexpress.com], who messed up shipping the scales took nearly 2 months to be delivered. Given the price it's difficult to recommend the scales over the Omron scales. Tanita do sell other these dual frequency segmental scales in the US, such as the BC-558 Ironman, but these retail for over $350 and don't write to memory card.[[File:Tanita BC-601.jpg|none|thumb|200px|Tanita BC-601are more useful.]] =Accuracy issuesIssues=Hydration can have a significant impact on the reading, so readings need to be taken at the same time of day with the same level of hydration. The [[Book Review - The 4 Hour Body|4 Hour Body]] recommend recommends drinking 1.5 liters (3 pints) of water, waiting 30 minutes, urinating and then taking a measurement. I have found that with the whole body scales I can simply measure when I wake in the morning and I get a consistent enough reading to not require this hydration procedure. The biggest problem for an athlete is that BIA is particularly inaccurate when fat free mass, including [[Glycogen]], changes<ref name="BIA1"/><ref name="BIA2"/>. I've noticed that the day after a long run, the scales claim a much larger loss of body fat than is reasonable. Studies have shown that obesity is underestimated with many body fat scales.==Optimizing Accuracy==My approach to optimizing my scales accuracy is average and calibrate. My Tanita BC-601 scales offer several activity levels, so I find the level that matches a more accurate body fat measurement such as a [[DEXA Scan]]. I then use an average of a week's readings to even out any hydration errors. =Details=Posture and Accuracy==Body fat With BIA scales work by comparing it's important to get the posture just right, as even small variations in the electrical resistance position of your arms can make a direct current significant change to alternating currentthe reading. You must hold the handset with your arms at 90° with your elbows straight. {| class="wikitable" |- valign="top"[[File:Omron HBF-510 correct posture. jpg|none|thumb|x300px|The direct current does not penetrate the cell walls whereas the alternating current doescorrect posture.]][[File:Omron HBF-510 posture errors.jpg|none|thumb|x300px|Posture errors. This creates ]]|}=Recommended Scales=I have tried a difference that allows an estimate number of extracellular water. Typically scales over the years and I believe the alternating current Omron HBF-510 is around 50 kHzthe best value for money, with dual frequency but the Tanita Segmental scales adding in 6.25 kHz may worth the extra cost for their improved accuracy. Single ==Best Value - Omron HBF-510==The [http://www.amazon.com/Omron-HBF-510W-Composition-Monitor-Scale/dp/B001IV61J4 Omron HBF-510], which retails for about $60-$65 offers great value for money and are one of the cheapest BIA scales that measure from the hands and feet, though unlike the other scales here, they are not dual frequency or segmental. ==Cheapest Segmental - Tanita FitScan BC-601F==The [http://www.amazon.com/Tanita-FitScan-BC-601F-Segmental-Composition/dp/B006QYDMC2 BC-601F] is one of the cheaper segmental BIA scales generally treat at around $260. However, this scale does not record the body data for easy transfer to a PC. This is more of a single cylinder problem with uniform resistancea segmental scale as there is far more data available. ==SD Storage - Tanita BC-601==The [http://www.amazon.co. Unfortunately because the arms uk/Tanita-BC601-Innerscan-Segmental-Composition/dp/B0037252RY Tanita BC-601] available in Europe and legs are thinner than writes the trunk they contributed disproportionate amount of resistancemeasurements to a flash memory card for direct transfer to computer, which I find invaluable. ==Wireless – Tanita BC-1500==The [http://www.amazon. Typically arms and legs are about 5 to 20% of body weightcom/BC-1500-Ironman-Wireless-Segmental-Composition/dp/B006OQO6MW BC-1500] does not have a built in display, but form about half of wirelessly transmits the overall resistancedata to a PC which is ideal, while especially if you combine it with the trunk contains 50% of the body mass and contribute only 5 to 10% of the overall resistanceoptional [http://www.amazon.com/Tanita-D-1000-Tabletop-Display-BC-1000/dp/B004MEX9UI D-1000 display]. Dual frequency scales on the other hand segment the body up into five cylindersHowever, two for the arms to for the legs scale is $620 and one for the trunkoptional display is $75, giving much higher accuracyso this is an expensive option.==Not Recommended - Withings WiFi Scales==The [http://www.withingsamazon.com/enWithings-WS-50-Smart-Analyzer-Black/dp/bodyscale B00BKRQ4E8 Withings body fat scale] is noteworthy because it is Wi-Fi enabled. This allows it to and provides a direct upload the data directly to the Internet where it can be viewed on any web browser. This makes it easy to visualize and track the changes in your weight and body fat. Unfortunately the scales only measure between the feet, and so their body fat accuracy is too limitedto recommend.
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