I have fairly old bodyfat scales, measure myself once per week, and find it consistent with the readings from my gym, currently around 16%. However, I went to update my tired looking scales recently, and found the new ones read 28%!! I took them back to the shop and tried another set the same brand, and got the same result. I then tried another brand, and got 8%!! At that point I gave up and got a refund. I was tempted to keep the low reading scales though :-)
Over the weekend I got a phone call from my friend Natalie.
She was a bit frustrated, and understandably so.
You see, about a week ago (per my recommendation) she purchased an electronic body fat scale to track her progress as she attempts to diet down for “beach season”.
Unfortunately, for the last week, the readings have been all over the place.
“One day it says I’m 26% and then the very next day somehow it reads 22%. Then back up to 24% the next day. It makes no sense.”
Perhaps you can relate.
Without a doubt, these scales can seem pretty worthless if you don’t really understand a) how they work, and b) how to use them to produce reliable, consistent data.
On the other hand, when you’ve got “A” and “B” down pat, body fat scales can be an invaluable tool to easily track body composition without having to bust out a pair of calipers or set up an appointment to have your body fat evaluated at your local gym (which has its own set of accuracy problems).
Today I’ll clear up the confusion and tomorrow you’ll actually be able to use the body fat function of your scale to produce some meaningful data.
First, let’s cover how they work:
Electronic body fat scales use a technology called bioelectrical impedance (BEI) to assess body fat.
With this method, a very light, unnoticeable electrical current is passed through the body and the percentage of the current that is repelled and the percentage “absorbed” or conducted are both measured.
The assumption is that body fat will repel the current while all lean tissue will act as a conductor, leaving the percentage repelled as your estimated body fat percentage.
Here’s the problem:
This method is highly dependant on consistent levels of body water, something that is not often consistent to say the least.
This is where both your and Natalie’s frustrations come in.
For example, if you just exercised or are dehydrated, the measurements will be off. If you have a different level of body water than when you last measured, the measurements will be off. If you take your body fat in the morning, and then again in the evening, the measurements will be off.
In other words, in order to get consistent readings, you have to be consistent in your measurement practices; this is what I recommend:
Body water is at it’s most stable point every day first thing in the morning before eating and drinking anything. This is when you should be taking your body fat readings.
Another recommendation is to only measure at most twice weekly. There are too many fluctuations that happen from one day to the next, and it’s flat out psychological torture to be stepping on the scale every day.
I do not allow my clients to get on the scale but once a week-period. And if they email me with concerns about scale weight being up from yesterday, I simply respond with “Give me an update on Saturday morning.”
Be consistent with your measuring practices and you’ll be surprised just how consistent your measurements become.
And lastly, always use multiple methods of tracking progress-scale weight, body fat %, and girth measurements are all part of the equation (with the most important of those being girth measurements; if clothes are getting loser and “problem” measurements are going down, you are undeniably getting leaner, regardless of what the scale says).
So how about you? Do you use a body fat scale? What other methods do you use to track progress?
At least 100 comments and I’ll be back before you know it with more VIP blog content!
Talk to you in the comments section,
Joel
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@Michel – Hi Michel. If you have gotten stronger at the same bodyweight, how do you know that didn’t come from improved neural-muscular conditioning, i.e., same muscle (and same fat) but you are now able to recruit more muscle fibers when performing the movement/exercise. Hence, in theory, you could actually be fatter whilst being stronger at a certain movement pattern! But it isn’t likely in practice. It’s hard to think of too many scenarios when that might happen, other than in special cases.
Cheers,
Mavro.
Hi Joel,
– Yes it is, I use a body fat scale, but only once each 3-4 weeks never before.
– I always the measure of my weight is the first thing I do in the morning before everything, well after piss. Always in the nude.
– I prefer the calipers, but I haven´t it.
– When I want to know the % of fat usually I´m not only go to the gym to trainning hard but also I go to the Sauna at least 15 min. each day or two days. If I don´t do that my lost of fat(%) it´s really low. My problem actually it´s that my work don´t let me invest too much time at the gym, I´m a Vet and I have an Animal Hospital.
– To measure the body fat % can be depressed, because many times you can lose weight and your body fat % be similar. More over, to lower the body fat % when you are thin or at least not too fat required more time, be patient and to be perseverant (don´t give up just keep going trying it, doesn´t matter the difficulties you are strongest an you will reach it).
I have used a body fat scale for several years with very good results. At first I had to figure out how to program it for an athletic body build, as the standard setting is not right if you already have a lot of muscle. With the athletic setting, I measure each morning, right after I get up and use the bathroom. I get very consistent readings this way, and have had them confirmed by the gym. I really appreciate being able to see my progress in building muscle when it is not apparent from weight loss or tape measurements (and who wants to tape measure themselves every day?).
I find that my body water % varies considerably even in the morning. Consequently the body fat % varies. So I find the scales next to useless in assessing my progress – an expensive toy. Taking measurements only once a week would only cut out the daily variation. If I weigh myself on a Saturday, the result will still depend on my level of hydration at the time.
I think a tape measure would be more accurate.
I have calipers and found them to not be accurate enough to distinguish 1 – 3 pound differences. I use tape measurements once a month and I use a body fat scale that measures weight, body fat, muscle mass and bone mass. I take a reading every morning as soon as I get up, before getting dressed or eating or drinking anything. I write all the readings down and I tally them up after 7 days and take a weekly average. I know that the body fluctuates significantly one day to the next, so I don’t like to take a once per week only reading as that could be a “high” or “low” day. I like taking the average of the whole week. Feel that’s more dependable. Then do the same thing the next week.
I bought one of these scales a couple of months ago, and do get some pretty wide variations in the BFP reading. I’ve wondered whether, since I’m a classic pear shape (unusual for a guy, but I had extensive lower abdominal surgery 10 years ago and have a massive scar that the surgeon said was like a stick pushed down on a sealed plastic bag – the sides bulge much further out).
One factor the instructions with my scale emphasized (besides total body hydration) is the moisture on the skin of the feet. I do know that the rare occasions I’ve gotten on this scale which were not right after a shower, the reading is very different (or it errors out saying it can’t get a reading).
I’ve seen a model in some catalog that has a hand-held unit that contains the readouts, but also seems to have the electrodes so the current isn’t just going from one leg to the other, but more throughout the whole body. I wonder if that would be more accurate.
We have a set of these scales with a hand held monitor for fat and water. My partner has no problems with it and we have tried it on other people but every time I try to use it I just get an error reading. Any idea why this might be?
Best thing to do is follow the old school way; buy or use the pair of jeans that you are dreaming to get into. Once you are comfortably fit, you know you have reached your goal; few days later if they are loose on your waist; wola!!!! you have not only kept the fat off, but you have lost some more.
Although reality car is always speeding on the opposite direction; LOL!!!!!!
hi joel,
thanks for the info! but i’m sure there are some scales that are more accurate overall than others. which brands/models would you recommend for the best combination of accuracy and affordability?
Own one works okay found that measuring in the morning gave me higher body fat due to the lake of water in the body. The scale company rec. right before supper but record water percentage as well if they are close to the same the body fat is closer to being accurate. This electric charge through your doesn’t cover the whole body, just from lower chest down so if you are loosing weight or building muscle in the upper body, back chest shoulders and arms but the body fat still sticks to the hard to loose places, stomach hips and rump the the scales don’t show your progress
I think the best thing is the mirror. I dont use a body fat test. I dont almost ever weigh myself (diffrent scales tell me different things).
Another way that i use sometimes is to look at the folds of my skin around my belly when i sit down. The thicker the flods the worse.
This method and the mirror worked very well for me
I always have this problem! But usually it varies within minutes of each attempt to measure. And I am consistent with timing of measuring.. maybe its a bad scale :(
i’VE ALWAYS USED THE FAT CALIPERS TO MEASURE MY FAT PERCENTAGE.
THE INSTRUCTIONS STATE TO MEASURE IN THE SAME PLACE EVERY TIME.
I HAVE ALWAYS CHOSEN SUNDAY FOR THE MEASUREMENTS DAY AND I ALWAYS LOG EACH WEEK, GOOD OR BAD !!!
Joel. I have an iron man scale by Tanita. Weight, fat% hydration level, body muscle as well fat and muscle of each limb and Torso, Metabolic age and visceral fat.
I weigh every day at 5AM on arising but do not get excited as hydration level will vary from 51% to 54.5% and changes fat%, 23-28, muscle in each limb etc even visceral fat and metabolic age. My main point is if I see fat% up I check hydration level which will be low and vice versa. Hope this helpful.
PS I have tried some water up a gal and a half and can not seem to effect my hydration level (Weird but true)
Tom J
I have a body fat scale that is all over the map on readings, despite my absolute consistency in when I get on (first thing in the morning). I had hydrostatic immersion body fat testing in February 2008 and then again in February 2009, neither of which matched what the scale said. I feel very confident in the hydrostatic testing – it said I had lost 6% body fat in that year and 12.6 lbs., which means I had lost less than one pound of muscle – the rest was fat.
I use caliper and tape measurements, but the results are not very close:
Jackson/Pollock 3 Caliper Method – 4,65% of fat
Tape Measurement Method – 13,86% of fat
How can that happen?
And advice to Russel about a mirror method – people see what they want to see. It is not the best method. My opinion. Maybe it works for you…
It seems to me more and more that the more liable sources of bodyfat measuring are the mirror and some pics.
Hi jOEL,
I can relate to this problem, so much so that I shelved the scale and went back to the regular one. Now that you’ve explained how best to use it, I’m going to get mine out again and use it properly this time…I hope! Thanks!
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Hey, it’s Joel! So you want to know a little more about me, huh? Well, I’d be happy to oblige :-)
I guess it all started back in 2001 (my freshman year of college) when I was just a “skinny fat” 19-year old kid. At the time, I was spending close to 2 hours a day in the gym (now my workouts last about 30 minutes), and despite my efforts, you’d probably never guess I worked out a day in my life by looking at me...