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?
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Talk to you in the comments section,
Joel
Hi,
So far I’ve been using the services (although not free) at my local gym to have my meassurements taken. Party due to the inconsistency-problems with the BEI method I’ve heard about. Now that I’ve read how to take meassures in a better way, I might be getting me one of those scales with the built in fat meassurement function. Thanks for the info!
/Per
The only things I use with regards to body fat measurement are…
1) A measuring tape (MyoTape, works quite well since it’s just me doing measurements)
2) AccuMeasure calipers
3) Once a week, a weight check, and this is only to gauge any changes in body fat (differences in body measurements).
But the most important thing of all that I use is…
4) A mirror. Nothing beats looking at yourself and seeing where any progress has been made.
I used a body fat/hydration scale and it always seems like the 2 measurements are in kahoots. Hydration is up, body fat down and vice versa. You’re also right on the measurements being a good gauge. I’ve been working out for 3 weeks, dropped 26 inches but the scale hasn’t moved. The odd thing is that the body fat number hasn’t really changed either. Things that make ya go hmmmmm…
hi joel, i use a body fat scale also, for quite a few years. and i only weigh up once a week, saturday mornings a little after i get up. totally naked,and my water percentage is always above 50%. my fat % is a little high, the lowest i had it at was 18%, right now it goes around 22-25%. i’m trying to get that down yet, but it’s not easy,most of it right now is in my belly.
thanks dennis
I don’t really use any devices to keep track of my progress. Every morning I take a look in the mirror and I think that’s the most accurate way to track progress. It’s rewarding when I start to see definition in areas that I’ve never had any. Devices can only tell you so much, you actually have to take a look at yourself to see if you’ve made any progress and if you need to work harder or keep doing what you’re doing
I recently had a measurement done with the type that requires the user to grab the handles and hold them out front at arms length, shoulder level. It measured me at 17%. I am measured with skin fold calipers, regularily at under 10% by a very competent trainer who has measured hundreds.
While taking your above advice may provide some consistency, that doesn’t necessarily make it accurate. I would love to see some comparison analysis of the BEI vs. skin-fold vs. hydrostatic.
i check y weight scale almost everyday i’m 51kg then goes upto 53kg,workout 12midnight without drinking water when i have breakfast i drink water.i loses y inches then on weight scale up and down.
26 inches in three weeks? Lipo?
Anyway, thanks, Joel. Now I know why I’ve gotten such inconsistent readings on my body fat percentage. I’ll begin testing this out immediately.
Joel: Thanks. I was considering buying one of those devices. I may yet do so, but at least now I know what I’d be getting myself into.
Bill
i do breakfast 1 hr workout then for lunch 12pm before hr then for dinner 6pm before 1hr each of them different workout for blast fat. then 10pm stretching workout.
I used them for a little while when I was seeing a nutritionist to try to gain weight (for which there isn’t a whole lot of info readily available – I guess it’s easy for most people). The value did seem to fluctuate a bit, but it sounds like that may have been partly due to the fact that I saw her after work, rather than in the morning. I’ve never tried any other measurement, though. Mostly I just use my parent’s scale every week or so when I visit them to see if I’m gaining anything.
Hmm, I too have concerns about the accuracy of Body Fat Scales.
For example, I am losing body fat, I can see it in the mirror but my muscles are growing. yet, the results are still the same?
Another concern is that the bioelectrical impedance (BEI) does not travel around the whole body to measure the body fat it only goes around the lower part, possibly including the bladder, in the case of the standing devices and there are others that you hold handles that would measure probably the upper body.
I guess that the answer is that if you use the same device, at the same time, ensuring that the conditions are roughly similar i.e. you’ve been to the loo then the results should be comparative.
I baselined my device (a reasonably expensive device) against a commercial model and found that my scales were out by 4lbs! I forget what the body fat equivalent is.
Fat percentage readings vary for me by 3 percent. Sodium and water retention is a biggie. I’ve found that my scale’s usually under reporting my body fat, so I always get the calipers.
I have used these scales for quite a while. I have found that the measurements vary within the day and from day to day. I have found that from week to week, they are extremely consistent if your measure at the same time and on the same day of the week. For me, this is upon waking on Friday.
@TW – I have been doing body fat measurements for weight control athletes since 1973. Believe me when I tell you body fat measurements are at best an approximation. The only accurate measurements are off of cadavers;not recommended. Use the body fat measurement as a tool to judge your progress with your plan. If it’s moving in the right direction your plan is working; if not, change your plan. Joel’s advice is right on-use the same measuring device under the same conditions to get a consistent approximation of your body fat. Stay strong and healthy.
The most accurate method I have found is to take a picture of myself. Looking in the mirror doesn’t seem to be as accurate as a photo. You can see just where the fat is hanging on
Joel, this is a great timing for me. I had seen a scale that measured body fat at my local SportsAuthority but wasn’t sure how they worked, what to look for, etc. especially when they all had different prices.
What it seems like is that it’s a good thing to have when you use it appropriately. I only get on the scale once a week, the first thing monday morning. No food, no water, just after using the toilet. I think the body fat aspect of those scales will be good, but I agree the body changes too much to be so random about checking.
Any suggestions for a recommended body fat scale?
My thoughts are that as long as the measurement is consistent, does it really matter what the reading says, so long as you are showing an improvement on the same scale, with the same measurement technique at the same time of day in the same condition. Whether you get a 14% reading from the BEI or a 12% from the calipers is irrelevant so long as you are showing progress with the same measurement from one week to the next.
I am looking to gain weight and only need minimal fat loss
I use a tape once a month
I use calipers and a scale every week to determine how much muscle and/or fat I am gaining/losing and adjust calories and protein/carb/fat ratio up/down depending the results
I have given up on my Tanita. I used to measure only when I first awakened. The day after I do cardio, weight is down, BF up. The day after I lift, weight is up and BF down. The stress released cortisol and created doubt. I am much happier letting it collect dust in the closet.
D
Hi
I usually lose weight in my face first, in other words, my cheekbones are more defined, and other bone structures, such as those just below the neck become more visible. Also, if I’ve lost weight, its much easier to pull in my stomach and see some definition :)
I just use good old fashion analog scale. And tape measure once a month.
Probably I should get those fancy body fat tracking scale.
I have a scale with the body fat % feature, but it always errors out on me. It can read. My husbands fine, but not mine. There are 2 spots o the scale for each footanr I think that it may be because I have small feet and they barely touch both metal spots on the scale? That’s dumb, but I guess I should just get a new one soon?
I do not have, or use a bodyfat scale, I track my progress using the mirror, the weight scale, and my current strength levels. for example:
If my weight stayed the same and I’ve gained strength I know I have added some muscle & lost the same amount in fat.
If I lose weight and I didn’t lose strength I know I’ve lost pure fat.
Joel, My goal at age 54 was to have six pac abs. I wasn’t sure if it was possible to do at 54 but I went for it. I started at 22% body fat according one of those devices you hold out and it calculates your body fat. That was the last time I measured. I have read several coaches theories about body fat % and having a six pack. I started following the nutrition advice of the experts to burn body fat and I mix up several ab exercises every other day. I don’t even weigh myself but I am going broke buying pants. I now have a good six pack so I guess my body fat % must be fine. I worry about eating right and sticking to my training and I really don’t have to measure anything to see what my body fat % is. Eating right is the first thing that must be done and everything else just falls into place.
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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...read more