Had a Body Fat and BMI Test today...

[Jth1]

So, I had a Body Fat % and BMI test done today with one of those handheld things (a bioelectrical impedance test), and had a few questions about it, and what the lady administering the test had to say.

First off, I started doing my current workout schedule in Jan. (running 3 times per week, walking on 2 off days, weight training 3 times weekly), and when I first started, I used a method found on JSF to estimate body fat (a military method if I recall), which told me I was at around 28-30%. When I had the test done today (pretty much exactly four months later), it came back as 19.7%. Maybe I'm wrong, and maybe I messed up the results of my first self test, but it seems like a pretty big amount to drop in that time, considering I've only taken off a little over 20 pounds.

Secondly, she made a comment about my BMI being 28.9%, but didn't really explain why other than saying that with that BMI, she would have thought my body fat % would have been higher. I'm completely clueless as to why, so I figured I'd see if anyone else had an idea.

Lastly, she gave me some flat out bad information. She told me that for weight loss, weight training wasn't useful, and that if I've been weight training for this long, I wouldn't be gaining any more muscle that would interfere with my weight loss. Don't get me wrong, while trying to drop weight (and working in a calorie deficit), I don't expect to be getting bigger by leaps and bounds, but I don't see any way that it would be accurate that I wouldn't gain any muscle whatsoever.

So, I guess my main questions are if anyone has tried those handheld BMI/Body Fat testers, and how accurate they've found them to be, and what would seem so wrong about my BMI to Body Fat numbers. Sorry, I know this got a little long, so thanks in advance for any input you may have.

[deus ex machina]

Took me a few seconds to realize what you were talking about, but yeah, I know what you mean. I had one taken a LONG time ago, and if I remember correctly, the one I had taken was pretty reliable, it was like half your results I think, but that was just once and it's been years. Sorry.

Deus ex Machina

[RTE]

Originally Posted by Jth1

So, I had a Body Fat % and BMI test done today with one of those handheld things (a bioelectrical impedance test), and had a few questions about it, and what the lady administering the test had to say.

First off, I started doing my current workout schedule in Jan. (running 3 times per week, walking on 2 off days, weight training 3 times weekly), and when I first started, I used a method found on JSF to estimate body fat (a military method if I recall), which told me I was at around 28-30%. When I had the test done today (pretty much exactly four months later), it came back as 19.7%. Maybe I'm wrong, and maybe I messed up the results of my first self test, but it seems like a pretty big amount to drop in that time, considering I've only taken off a little over 20 pounds.

Secondly, she made a comment about my BMI being 28.9%, but didn't really explain why other than saying that with that BMI, she would have thought my body fat % would have been higher. I'm completely clueless as to why, so I figured I'd see if anyone else had an idea.

Lastly, she gave me some flat out bad information. She told me that for weight loss, weight training wasn't useful, and that if I've been weight training for this long, I wouldn't be gaining any more muscle that would interfere with my weight loss. Don't get me wrong, while trying to drop weight (and working in a calorie deficit), I don't expect to be getting bigger by leaps and bounds, but I don't see any way that it would be accurate that I wouldn't gain any muscle whatsoever.

So, I guess my main questions are if anyone has tried those handheld BMI/Body Fat testers, and how accurate they've found them to be, and what would seem so wrong about my BMI to Body Fat numbers. Sorry, I know this got a little long, so thanks in advance for any input you may have.

BMI only takes two factors into consideration - height and weight. The gadget attempts to determine your %fat by allowing a small current to pass thru your body. There are many factors that would affect a reading. The BMI is going out of favor for providing meaningful information. If you do have a 19% bodyfat, it would be out of line with a BMI reading. It certainly is possible that 4 months of work could make the difference and reduction in bodyfat. Her statement on the weight training show utter ignorance the type you see in many gym workers, these days.

Just consider the test and her coments a waste of time and stay on track. Take measurements, keep records, and look at your naked body in a mirror. you will see results.

[J_W]

Originally Posted by Jth1

So, I had a Body Fat % and BMI test done today with one of those handheld things (a bioelectrical impedance test), and had a few questions about it, and what the lady administering the test had to say.

First off, I started doing my current workout schedule in Jan. (running 3 times per week, walking on 2 off days, weight training 3 times weekly), and when I first started, I used a method found on JSF to estimate body fat (a military method if I recall), which told me I was at around 28-30%. When I had the test done today (pretty much exactly four months later), it came back as 19.7%. Maybe I'm wrong, and maybe I messed up the results of my first self test, but it seems like a pretty big amount to drop in that time, considering I've only taken off a little over 20 pounds.

As a beginner you can gain muscle and drop fat at the same time. So you wouldn't lose that much scale weight but you would drop quite a bit of body fat. You didn't give us your stats. How much did you weigh when you started out? Over what period of time did you drop the 20 lbs? Are you still taking tape measurements?

Secondly, she made a comment about my BMI being 28.9%, but didn't really explain why other than saying that with that BMI, she would have thought my body fat % would have been higher. I'm completely clueless as to why, so I figured I'd see if anyone else had an idea.

BMI isn't given in %. It's a ratio that is arrived at by dividing your weight in kg by your height in meters squared. So if you were 200 lbs and 6'0 tall, your BMI would be 27.16. For people with a lot of muscle and little BF the BMI is useless. It's an okay indicator of obesity for sedentary couch potatoes.

Lastly, she gave me some flat out bad information. She told me that for weight loss, weight training wasn't useful, and that if I've been weight training for this long, I wouldn't be gaining any more muscle that would interfere with my weight loss.

Do you just want to drop scale weight or do you want to change your body composition? Because if you just want to lose weight, you could just chop off your arm . In other words, she doesn't know what she's talking about.

So, I guess my main questions are if anyone has tried those handheld BMI/Body Fat testers, and how accurate they've found them to be, and what would seem so wrong about my BMI to Body Fat numbers. Sorry, I know this got a little long, so thanks in advance for any input you may have.

Those devices (just like the BF scales) are notoriously unreliable. Mine puts me at 27% BF while my calipers say 18%. They're mostly useless.

As for the second part of your question, like I said, the correlation between BMI and BF only works for people who don't weight train. Just look at John. He's about 195 with a BF of 10%. That means that according to BMI he's overweight .

Originally Posted by rtestes

Just consider the test and her coments a waste of time and stay on track. Take measurements, keep records, and look at your naked body in a mirror. you will see results.

Agreed!

[1FastGTX]

Originally Posted by rtestes

Just consider the test and her coments a waste of time and stay on track. Take measurements, keep records, and look at your naked body in a mirror. you will see results.

Agreed here as well!

[Thrust]

While you're cutting, the mirror is the most useful tool in your arsenal for tracking your progress. I've got a Tanita BF scale and it's good at picking lottery numbers

[guava]

What kind of facility did you have the test done at? Based on the comments of the person who did the test, I'm guessing it was a weight loss clinic or something similar, rather than a fitness club.

I think most of the girth comparisons like the miltary method give a pretty inaccurate measure of body fat percentage, but sometimes the bioimpedience ones can be off by quite a bit too. However, if you use the same tests over a certain period, you can at least see a trend in your body fat percentages.

The reason she was surprised about your somewhat low bodyfat percentage as compared to your BMI is because she's not used to testing people with so much muscle mass! Typically, people with a higher BMI also have a higher percentage of body fat. Unless they weight train. Be proud!

I agree that it's bad information that weight training does not lead to weight loss. But it's more concerning that she views "weight loss" as an improvement to a person's health. It's not, so much as "fat loss" is an improvement to a person's health.

Since January, you've lost a higher proportion of fat, and maintained a larger proportion of your muscle mass than a person typically would on a standard weight loss diet. That's a great thing for both aesthetic purposes, strength, bone health, and general health. Well done!

[Robert2006]

The military test is a formula right? Plug in neck,waist whatever and come out with a number? The problem with all the formulas is they assume a certain body type average with fat stored in certain places. If your body is different then the assumptions they won't work well. I lost weight intially in places like my neck. So the formulas underestimated for me.

BMI is just a flashing light sort of thing. It's supposed to say to the tester [Your doctor for example] to check further or not. A high BMI like the others have mentioned might just mean lots of muscle. A low BMI might just mean no muscle mass. So either a low or a high number is a signal to check why the number is out of the range.

For bigger guys you have a fair bit of muscle to begin with. The goal is to keep hopefully all of it while dropping fat. Think about we hauled around lots of weight and our bodies needed muscle to do that. If you can drop weight but keep the same muscle mass you'll be doing well.

[Jth1]

Originally Posted by J_W

As a beginner you can gain muscle and drop fat at the same time. So you wouldn't lose that much scale weight but you would drop quite a bit of body fat. You didn't give us your stats. How much did you weigh when you started out? Over what period of time did you drop the 20 lbs? Are you still taking tape measurements?

Oops, sorry about that. I'm 6', started at 235, and last I checked (a couple of days ago), I was down to 213. I started with very light cardio and weight training maybe twice a week in November, December was such a mess that I don't even count it, and got a little more serious about it around the beginning of Jan.

Unfortunately, I didn't start taking (or at least keeping) tape measurements when I started, so I don't have anything to compare against, but I guess there's no time like the present to start.

Originally Posted by guava

What kind of facility did you have the test done at? Based on the comments of the person who did the test, I'm guessing it was a weight loss clinic or something similar, rather than a fitness club.

It was actually at a health fair kind of thing, where they have medical people come in if you have any questions or want to "start living a healthier lifestyle" type of thing.

Originally Posted by guava

The reason she was surprised about your somewhat low bodyfat percentage as compared to your BMI is because she's not used to testing people with so much muscle mass!

Haha, I wish. Gave me something to laugh about though. But, hopefully with enough work, I'll get there.

[why_not_fandy]

The bioelectric impedence device you used gave you information on you body fat percentage (19.7%). These devices are ok for measuring body fat % (fairly reliable-will give roughly the same results for the same person), but have validity issues (have varying accuracies for different people). Some of the factors affecting accuracy are hydration level, activity level, and I believe body fat% and distribution (sounds ridiculous, right). I think morbidly obese people experience more error with Bioelectric impedence. I believe the level of error for a four site Tanita device is +/- 9% assuming no operational error.

BMI does not give a body fat %. It is merely a number to be compared with national standards, and is calculated as your weight in kilograms divided by (your height in meters squared): kg/(M^2)