Are Body Fat Scales Useless?

LOL!!!@ Philip:

I see one member mentioned BMI – am curious to know Joels take on BMIs. In my experience they can give wildly inaccurate readings for athletic/muscular people (whilst I can see how useful the readings are for non muscular people). I myself am quite athletic and I generally come out as Obese (…or like Morbidly Obese or whatever the most obese reading is called..) with a BMI reading, while in real life I am nothing of the kind….I was a gymnast all my childhood and I had Doctors baffled when I was a teenager with my “obese” reading, yet pretty ripped appearance, normal sized clothing and great fitness level. I have seen the same thing with most of my friends who carry a lot of muscle. Joel – what’s your BMI?

Thank you for addressing this! I use a body fat scale and the different readings have been a frustration of mine too! Because of the different readings I was getting, I started experimenting a bit and noticed that there was even a difference in the two readings I would take before and after a shower. Your comments about body water content account for the difference. I’ll follow your advice and not get worked-up over the differences. Thanks Joel!

I have some Salter brand Scales and they do the same as mentioned in your article Joel. I always weight in the morning, but if my water is up my body fat is down, and visa versa. Also although my Body fat calipers are telling me I am losing fat, slow as it may be (Just got me a copy of XFLP so watch out body fat) my scales are not SO DON”T HAVE A LOT OF FAITH IN THEM REALLY. Final comment: I reckon the mirror is probably the best way to access your sucess.

Well, finally some wise words!!!
I always thought that not lbs are important but inches as body mass is a summary of water, muscles, fat and all you have in your digestive system.
Also, as I am a woman water and fat level is changing all the time during 28 days periods.
It is much more reasonable to check your effects once a week or two and always at same time of the day.
Cloths will tell exactly if you are getting closer to your goals :)
I do have one dress which is my best test: if I will fit in, it will mean that I gained my goal.

Ta

I measure at the Local Gold’s Gym once a week. It gives quite a detailed breakup of all the different things like BEI, FAT%, FITNESS SCORE etc. It is from this company called INBODY.

I have never used this regularly. I prefer a simple weighing scale and a measuring tape alongwith how I fit into clothes which matter more than anything else. I have improved dramatically with weight training and Interval Cardio training in the past 6 weeks. I hope to maintain this active lifestyle through the end of this year.

@ Cindy:
Hi Cindy,

taking the median and not the 7-day-average would be even better, since extremes are filtered out completely!

Mino

I use a Bowflex body fat scale, that you stand on, and hold a second sensor/control/display in your hands. It gives me percent body fat, and water, muscle and bone mass as well as the total weight of muscle in my body. It is very consistent. I always measure in the morning, ususally after a shower but before I work out. It also gives me what it thinks is optimal. I am 11% body fat according to the scale, and it thinks I should be 18. At 190 lbs I am not willing to gain 13 lbs of fat! I have checked it against an old caliper and they are within a couple of percentage points of each other. Best use is to forget the actual number and use it to chart trends.

I feel the same way about body fat scales. I own 2 body fat scales and 1 body composition scale that measures whole body. The truth is all 3 scales read a different weight, BMI, muscle mass and water %. I have found that if I move the scale to a different room – the number changes as well.

Obviously I track with a measuring tape and hip to waist ratio, but sometimes use the scale to measure my progress on creating lean muscle. This can get very frustrating.

My clothes are getting loser and I feel better – so I know I am on the right track – eventually the scale will catch up with me.

Thanks for the tips! :-)

Joel, Thanks for the information on the body fat measuring. On a different note though, I purchased the XFLD on the day it was released and did not get access to your bonus with the conference call. I am very dissapointed. Can you tell me what happened or is it too late?

Thanks, Leevone

I have noticed large variations when measuring body fat based on, before and after shower measurements. After shower numbers are generally lower. Which makes sense due to better conductivity in hydrated skin. Again consistency in your measurements is the key.

Even with early-morning once-a-week readings, the Tanita is all over the place. I have a Taylor brand scale at work which is better (as in more consistent with the caliper readings).

I rely more on my accumeasure calipers than any electronic devise. These also give different results whether you set them to read a man or a woman (you’d think fat amounts were fat amounts regardless, right?) athletic or no (same comment, if you have the fat, you have the fat, if it can actually read it then why the differences?).

When I also see these scales read my water % at below 45 I “lose it” because the human body is made up of much more than that, and I drink a good 3 liters of water/day, so believing them? Heck no!

Calipers, good, basic scales, and that’s it.

Let’s face it, everybody: Weight is not really the issue. It’s what you look like in the mirror. You don’t need even need a weighing machine. You know exactly what you want to look like. Who needs fat calipers, or fat measuring scales? You can actually see the fat! I suppose the real need is to see some early progress, when you start to try and get back into shape

I use the Tanita Body fat Analyzer. Have been using it for years and works perfectly.

I’ve also noticed, in every forum that’s had a discussion on these things, that they seem to work fine for men, but “screw up” when women use them.

Hi Joel
Is a body fat reading by the scales affected by calf/breast implants? i.e. does the electronic current recognise the implant as lean muscle or fat?

Hey Joel,

Agree with measuring up only in the morning.

Can you give some insight on the “InBody” equipment for this purpose? Its a brand that Gold’s Gym uses in my area – wanted to know if it uses the same principles / technology.

Thanks,
Ketan

It is perfectly possible to use a body fat analyser (BEI method), and take measurements every single day, as long as you understand that it will vary from day to day, and as Joel says are consistent with the time of day you take your measurement.

Even though I take a measurement each day, I’m less concerned with individual results, but much more interested in what’s happening overall. I use a charting technique the manufacturing & engineering industry have been using since the 30’s to interpret the results.

Oh the technique is ‘statistical process control’ or SPC, its a really simple visual way to determining whether or not something is/has changed over time.

That explains why the body fat scales at the gym gave such inconsistent readings!
So I bought some accumeasure calipers, but can’t work out how to get consistent readings.
I’ve now found a formula that uses body measurements to give a calculated body fat percentage, and it shouldn’t fluctuate depending on how much fluid I have in my body.

I have used a body fat scale for years. I weigh first thing when I get up in the morning and it does give me a good idea if what’s going on with my body. I watch it go down each spring and summer, then climb back up every fall and winter. I do notice, however, that sometimes when my weight is going up, my body fat percentage has gone down, and vice-versa.

You are right–there are too much variations daily to be much use, but you can get a sense for which way you are trending from week to week.

I use both BEI scale and a caliper test every other week at my gym. The scale test at home I do morning and evening just for fun. My scale at home tells me that I am about 22-23% body fat at 62 years old. The Pirillo format caliper test consistently shows me in the 8-10% range. The BEI scale at the gym also puts me in that range plus or minus 1%. The scale that you purchase can make a difference in tha accuracy of the results. The important thing to remember is that consistency of measuring format will show trends, no matter what the exact reading is.

My clothes are my scale. I do not use a scale of any sort, but I completely understand the need and attachment people have to the scale. It can be justifying for all the hard work and it is accountability for one’s diet, whichever direction they are going. I have found the scale to be too much focus for me so about 8 years ago i made the decision to throw it away. At the doctors i face the opposite way. I am a size 4 and very fit, my muscles weigh more, i know this, but it can be frustrating if i watch it numerically, daily, weekly or monthly. Weighing myself for me was not gratifying, it made my positiveness become negative. So if you know your body, and you are honest with yourself and you have a goal and are committed to it, you will get it without needing a scale…and you wont have to beat yourself up along the way for normal body fluctuations. Good Luck. Thanks Joel for creating this site and providing the knowledge we all love to continue to learn and grow from.

I have the Tanita Iron Man scale. It works good your advice to measure at the same time each day is sound. As you say the technology in these scales is dependent on youir hydration level. The downside of making a morning measurement is that you are dehydrated when you first get up. You will weigh less but your body fat % reading will be higher due to lower hydration levels. Tanita suggests measuring just before your evening meal but not after exercising. I have experimented with the scale quite a bit having had it for about 5 years and found Tanitas advice to be the most reliable way to use it. The Ironman scale provides a hydration level reading which is very useful for those days when your body fat reading is higher than expected, it directly correlates with your hydration level, lower hydration always equates to higher body fat reading. Knowing your hydration level takes some of the mystery and frustration out of the equation for you. I have correlated this scales readings to different caliper measurements and found that it is fairly close. I wouldn’t take either style of measurement as the gospel, however, all we really need to know is what direction we are moving in and all methods when properly applied work very well for that.

When using body fat scales you basically become a resistor and based on your resistance (impedance in this case) you get a value that relates to your %BF. It’s basic Ohms Law (V=I*R, where you are the R).

My gym teacher (back in college) always told me (and the whole class) to drink a lot of water (about a gallon a day) and keep hydrated for a least a day (preferably longer) to get an accurate reading from the machine.

Thanks Joel. That makes a lot of sense and I mainly use the bodyweight option of the scale more than once per week (though I have bagged that for the XFLD) and the bodyweight less often. Taking readings at the same allotted time per week is sure to make them more consistent.