December 9, 2011
UPDATE: There is a sort of a follow up to this post now up here.
I meant to do this review already some time ago since I’ve had the Tanita BC-601 Segmental Body Composition Monitor for six months now. However, I’ve at least had some time to gather data and to see how the device can be used to follow trends. I’m glad to say that it has been quite useful in this regard. This review, like all the others I’ve done, will be primarily from a personal perspective — there’s no use for me to try to be as comprehensive as possible since there are other bloggers out there that do a better job at this anyway.
Originally I was looking into getting the BC-1000, given its compatibility with Garmin ANT+ products, such as my Forerunner 310XT. However, rather stupidly, the BC-1000 is not in fact a segmental monitor, in that it doesn’t have separate analysis of the arms — it only has four electrodes as opposed to the eight electrodes in the BC-601 (at the same price point). Hence, the choice was obvious: eight electrodes and segmental analysis are bound to give you vastly more accurate results. There is a brand new model though (not yet on the UK website linked above), the BC-1500 Ironman version, which would appear to combine the good things of the BC-601 and the BC-1000, i.e. radio wireless ANT+ technology and segmental analysis.
The device is very easy to use and to setup, and it has performed immaculately. The interesting and important questions concern the accuracy and usefulness of the data. In terms of the accuracy, I can’t offer much more than anecdotal data, but at the very least the device does appear to be quite consistent, so it works for tracking trends. For instance, no matter what the device reports as your Body Fat percentage, if you see an increase in the weekly averages reported over a few months, then you can confidently conclude that there has been an increase. In what follows I will mostly comment on these aspects of the device.
Tanita BC-601 Segmental Body Composition Monitor
In addition to Body Mass, the device (not really appropriate to call it a ‘scale’!) measures Body Fat percentage, Body Water percentage, Basal Metabolic Rate, Metabolic Age, Bone Mass, Muscle Mass, and Visceral Fat Level. It also gives you a Body Mass Index (BMI) rating. The background data includes gender, age, height, activity level (1-3, from sedentary to strenuous exercise), and a setting for athletic builds. According to Tanita, an ‘athlete’ is ‘a person involved in intense physical activity of approximately 10 hours per week and who has a resting heart rate of approximately 60 beats per minute or less’. I satisfy both of these requirements, so I’ve been using the athlete mode. You get segmented results for Body Fat and Muscle Mass, for each leg, each arm, and trunk. Most of these are self-explanatory, but I’ve summarized the more complicated ones below towards the end of the review.
I’ve had the Tanita BC-610 for about six months, and although there have been some breaks due to travelling, I can make fairly confident judgements about long term changes in my body composition based on the device. All the data is recorded on a 64MB MicroSD card and is easily uploaded on a computer. The device supports four users and there are easy to use buttons to select the user. There’s also a guest mode and weight only mode. Tanita supplies a software called ‘Bodyvision’ with the device which can be used for rudimentary analysis. I have to say that my initial reaction to this software was that it must’ve been programmed in the eighties. It’s very basic and limited in what it can do. The raw data is of course available (and can be exported to a CSV file from the application), so if one wanted to engage in deeper analysis, this is possible. There is also another software available, from GMON, but it’s not freeware. You can download a trial version for free, which I did, but I was not convinced: although the software is slightly better than Tanita’s own Bodyvision, it’s still rather rudimentary and I’m not sure that it’s worth paying for. A pity really, since I love my data and would’ve liked to get a proper software for some goal setting and more comprehensive analysis.
The weekly averages of my Total Mass according to the Tanita BC-601 over the last six months. (Click to enlarge.)
Anyway, on to actual data. Above you can see a graph captured from the Bodyvision software showing the weekly average of my Total Body Mass. The turquoise section designates BMI below 18.5, which the Bodyvision software rather arbitrarily designates as ‘underweight’. Now, I was preparing for a marathon when I got the device, so I was looking to hit a race weight of not more than 58kg. It’s a bit irritating that the software has this built-in ‘feature’ claiming me to be underweight, but you’ll be pleased to see that more recently I’ve become ‘normal’. Over the course of the last six months, my total body mass has varied between 56.5 and about 61kg, the latest value being at 60.5kg. It’s worth noting that I’m only focusing on weekly averages here, as the daily values fluctuate according to the time of day, training, and other factors. I tend to use the device every day, and I try to do it fairly consistently before my evening meal, but there have been periods of a week or two of not using the device at all due to travelling.
During the same period, my Body Fat percentage has remained at a fairly constant 5.0%, occasionally jumping up to 5.7%. There’s a caveat though: it is my understanding, based on the limitations of Tanita’s other products, that the measured total body fat percentage only starts from 5.0%. Hence, I have no way to tell whether mine has been, or is, lower than that. Judging from the segmental fat percentage analysis, it very well might’ve dipped under it at some point: my legs vary between 1.0 and 3.0%, arms between 4.0% and 6.2%, and trunk between 6.8 and 8.2%. So, this seems like a peculiar limitation, since in the segmental analysis the range goes at least down to 1.0% (I’ve never seen a value lower than that). Of course, total body fat percentage of 5.0% does sound rather low, so another question emerges: how accurate is this result? I’m a pretty lean guy, but I don’t look that lean!
Well, I’ve been meaning to get reference data from some professional equipment, but that’s horribly expensive, so I haven’t gotten round to it yet. Interestingly, if I change to the standard mode instead of the athlete mode (which I’ve only done a few times), my total body fat percentage remains at 5.0%, but the segmental analysis produces different results: it about doubles for arms and legs, but goes down to 5.0% for the trunk. I assume that the athlete mode is more accurate here, as the trunk is likely to hold most of my body fat. Tanita claims that the accuracy of their bioelectrical impedance analysis for body fat is within 5% of the Dual Energy X-ray Absorptiometry (DEXA) analysis, which is considered the best method available; anecdotal evidence also suggests that my unit performs reliably, as two other people have gotten plausible results. Who can tell? I wish I could compare the results with an actual DEXA analysis, but the data is at least useful for observing changes over time, since the device does appear to be very consistent.
UPDATE: My body fat percentage has now been estimated with calipers, giving 7.1%. This is not directly comparable with the BC-601 data, as there was over a month between the measurements (and I ate a lot of cake in the meanwhile!), but the truth is perhaps somewhere between the BC-601 reading and the caliper test — so I guess it’s safe to say that the BC-601 gave a slightly lower value than the actual one. Still, I can live with the level of accuracy.
The weekly averages of my Total Muscle Mass according to the Tanita BC-601 over the last six months. (Click to enlarge.)
On to Muscle Mass. The first thing you might notice if you compare the muscle mass graph above to the earlier total body mass graph is that there is a close correspondence. I’m pleased to say that this is due to the gym work that I’ve been putting in: the 2-3kg of mass that I’ve put on over the last six months are all lean muscle. That should also be evident from the fact that my body fat percentage has remained virtually constant. My total muscle mass has varied between 50.95 and 55kg during this period, and the general trend is upwards. My arms have each gained just a few hundred grams of muscle, increasing from 2.75kg each to about 3kg each. There has been more fluctuation in my legs, varying from just over 9kg each to 10kg each. I’ve only recently introduced leg work at the gym, so I expect that I will eventually get to above 10kg muscle in each leg. The biggest increase by far has been in my trunk, which has gained some 2.5kg of muscle mass, varying from a low of 26.9 to a high of 29.5kg. I’ve invested a fair bit of time at the gym to my core muscles, and it shows both visually and in the data — although I’ve got some more work to do before we can talk about a six pack! The segmental muscle mass analysis is one of the features I value the most in the BC-601, as it gives you some accurate data about how strength training influences muscularity.
Basal Metabolic Rate (BMR) is the estimated amout of energy consumed at rest to maintain basic bodily functions. This number is of course influenced by the background data (as well as the other measured values), especially the amount of exercise you engage in during the day. For instance, based on my activity level (3) and with the ‘athletic’ setting on, the device estimates that at my current mass (60.5kg), I can consume 3462 calories each day to maintain that mass. That may sound like a lot of calories given that the usual daily recommendation for men is 2500 calories, and I’m very lightly built, but I think that the estimate is quite close to the truth: I do exercise about 2 hours per day on average on a good week. I can also confirm that despite consuming something in the range of 3500 calories per day, I have not gained mass significantly over the last six months (although I have gained some muscle). In fact, I should note that I have not found the BMR anywhere in the pure form, the device and the Bodyvision software only report the Total Energy Expenditure, which is the number I’ve been referring to above. Well, that’s the more interesting number anyway, so this doesn’t matter much.
Metabolic Age is generated by comparing your BMR to the average BMR of people of the same gender and in the same age group. One big factor here is lean muscle mass and body fat percentage, as muscle mass increases the BMR — the higher your BMR, the lower your metabolic age. In general, if your metabolic age is lower than your physical age, you are fitter than your peers. As metabolism tends to slow down as you age, this number is likely to increase. However, you can lower your metabolic age by keeping active and by having a healthy body fat to lean muscle mass ratio. Now, I tried to research the concept of metabolic age briefly, but there doesn’t seem to be an awful lot of solid science out there yet, so I’m not sure how useful the number is exactly. At any rate, it could be used as a general guideline since it takes into account a number of other factors that we are interested in. There are all sorts of online calculators for metabolic age, but they do not take into account your body fat percentage and lean muscle mass, so they will not tell you very much. With the Tanica BC-601 however, you get the best estimate based on all the data available. For instance, simply based on my age, gender, and height, I get a metabolic age of 23. I’m 29 years old, so the lower value is explained simply by my relatively low BMI (19.1). However, with the BC-601 I get a much lower rating; it reports my current metabolic age at 14.
Visceral Fat or Abdominal Fat is the fat surrounding organs in your abdomen. Hence, this is the type of fat you can’t so easily see, but it has been associated will all sorts of nasty diseases, such as heart disease and type 2 diabetes. The BC-601 gives you a visceral fat rating between 1 and 59, where 1-12 is ‘low risk’ and above that is ‘high risk’. Mine has been at a steady 1.
To throw some more data at you, the BC-601 reports that over the last six months, my Bone Mass has varied between 2.7 and 2.9kg, and Body Water percentage between 68.0 and 70.4%.
That about sums it up. As you can see, the BC-601 does give you a lot of interesting data, and it seems to be a very reliable device to monitor your general body composition trends, even if the absolute figures weren’t as accurate as Tanita claims. If I ever get a chance to get professional measurements, I will report back on the accuracy. In the meanwhile, I will certainly continue to use the BC-601 to follow my progress. Unfortunately, there will soon be a six month break in this, since I’ll be abroad and I can’t take the device with me…
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