Body Fat Scales – Do They Really Work?
By: Jodie Shield, RD
Many of you have asked me what I think about body fat scales – are they accurate? What’s the best one to buy? Do they really measure body fat? Well I confess: my favorite scale – if there is such a thing- is the doctor’s office upright scale. You simply step on, slide the markers until they balance, then read your weight. However, I realize this type of scale doesn’t tell you your body fat, BMI or any of the other handy measurements many of us want to know so we can analyze our weight and health. So I went undercover to my local Bed, Bath and Beyond store and bought a body fat scale. Here’s what I discovered . . .
My first dilemma: so many scales to choose from! Since I use to write for Weight Watchers and love their updated eating plan, I bought one of their body fat scales and decided to give it a try. This particular scale provided five key measurements: weight (in pounds), body fat weight, body fat percentage, body water, and bone mass. In addition, it contained enough memory to allow me to program the scale for up to four users. Check out my review of the Weight Watcher scale at the bottom of this article.
How do body fat scales Work? Most of these types of scales use bioelectrical impedance. That is to say, they send a safe and very low electrical current through the lower half of the body. Since the electrical current flows more quickly through water and muscle than bone or fat, the scale measures the speed of the current. Then based on that number, the scale estimates body fat using a multi-step, mathematical formula. One thing you will want to be aware of which was new to me: if you are pregnant or have an electrical implant such as a heart pacemaker or defibrillator these scales are not recommended.
Are body fat scales Accurate? Good question but the answer depends on several things. Body fat scale readings can be thrown off by the following factors. In addition,the results may not be accurate for kids under the age of 16, or people with an elevated body temperature, diabetes or other health condition.
- Hydration. If you’re dehydrated or sweat a lot from exercise or your climate, you will have less body water for the electric current to flow through. The result: your body fat reading may be higher than it really is. And the opposite is also true. If you drink too much fluid, have a full bladder, or if you are a women experiencing water retention from your menstrual cycle, your body fat reading may be lower than it really is. For best results: be aware of what affects your fluid retention; weigh yourself once a week, on the same day and at the same time of day; wear the same clothes or none at all.
- Movement. The electric sensors in these scales are sensitive and work best when weighing stationary objects. Wiggling around or quickly hoping on the scale can interfere with your reading. For best results: always stand on the same area of the scale platform and stand still.
- Foot calluses. Some studies have found that having thick calluses on your feet may prevent the electric current from flowing accurately. For best results: shave those calluses. (Did anyone say pedicure?)
- Muscle. Heavy-duty weight training builds muscle which weighs more then fat. This can result in a higher body weight measurement which can throw off the arithmetic in the body fat and BMI formulas (To calculate BMI, visit my home page.) For best results: if you do a lot of resistance weight training, these scales may not be your best option.
Great Gadget Review for:
Weight Watchers Conair Body Fat Scale (model #WW78)
Pros: I was pleasantly surprised how accurate the Weight Watchers body fat scale was for me. My weight was spot on, BMI correct, and my body fat percentage matched the reading I had confirmed by a personal trainer at my local health club. The initial set up took awhile, but after that using the scale was quick and easy. And it was fairly inexpensive $29.99. (The majority of body fat scales ranged between $30-$50 dollars.)
Cons: The five different readings flashed by way too quickly. And I had no clue what they meant. The owner’s manual came with some excellent charts which I would recommend you hang nearby or keep handy.
Healthy Eating For Families Recommendation: 4 out of 5 stars
posted by Jim on January 9, 2013
I have a metal hip implant. Would that effect the accuracy of the scale?
posted by Jodie on January 9, 2013
Great question! It sure would. This type of scale would not be accurate for you or anybody else with metal implants – knee or hip.
posted by Peter on September 16, 2014
Jodie, I’m confident the case will be the same; however, you mentioned knee/hip implants would affect the reading, but not leg rods. I have a titanium IM Rod/Nail from a broken tibia I suffered 13 years ago, and it’ll never be removed. Will this render everything but the weight metric off-kilter and if so are there any scales (w advanced features) that wouldn’t be useless for someone like myself? Kind Regards.
posted by Jodie on September 16, 2014
Hi Peter. Sorry to hear about your broken tibia! Your assumptions are correct! Good luck.
posted by Carole Hack on January 9, 2013
Great Article Jodi!
posted by Jodie on January 9, 2013
Thanks Carole! Hope it helped.
posted by Renee Colton on March 4, 2013
Truthfully – we know that we are fat, don’t we? I personally hate any type of scale. Mirrors don’t lie nor do our clothes. I don’t use the scale, I look in the mirror.
posted by iamtig on April 4, 2013
I agree on the numbers flashing by quickly. I have the HoMedics name brand BMI scale and need to use my smart phone voice recorder to quickly take note of what my readings are.
I have also learned that if the scale has all it’s feet on the ground opposed to if there is a foot or more on a bathmat, I will get different readings. Not that they are inconsistent with each weighing, ie, every time I weigh with the a foot on the bath mat, it provides consistent readings. Same goes for when all the feet are touching the floor, but those readings will be a few decimals off from if feet are on the bath mat.
posted by stummee on April 13, 2013
That scale did not get a good review in Amazon. Plus I read from several sources body fat measurements from scales is pretty inaccurate. The writer didn’t look into this enough.
posted by Jodie on April 13, 2013
Thanks for your comment. Do you have a scale you recommend?
posted by Mila on June 3, 2013
Is it ok to this tipe of scale for babies/small kids just to masure their weight? So you use it just like a regular scale. My scale has that option when you use it like a regular scale and option where it masures body fat/water…
Thanks!
posted by Jodie on June 3, 2013
Good question! Since a child’s BMI and body fat is not calculated in the same way as adult’s BMI or body fat, this type of scale would not provide accurate readings for those measurements. However, you could use it just for weight if your child is willing to stand still. When my children were young, I use to weight myself first, then weigh myself holding a child and then subtract my weight from the total combined weight to get my child’s weight. Hope this helps!
posted by Mila on June 3, 2013
Yes, that how i it too. But our old scale wasnt accurate any more, and hubby bought this one now that massures all this things.
Thanks for replay!
posted by Andrew Chan on June 3, 2013
Hello, I just used a Bioelectric Impedence scale and it said that I have too much fat, too little muscle and that I have the body composition of a 36-year-old. I’m 28, I kickbox, I occasionally lift moderate to heavy weights and I rarely eat junk food. I measured myself right after a hard workout so I’m kind of curious what happened. I’m 5’7″ and way 158lbs. I’m not fat or skinny so I’m not sure what is going on. Is my health in danger?
Thank you,
Andrew C.
posted by Jodie on June 6, 2013
How frustrating for you! Sounds like you are doing a really excellent job of working out and trying to eat healthy. As I mentioned in my blog post, these scales are not for everyone. Hard for me to say for sure what happened. However, if you are concerned about your health, I highly recommend you give your doctor a call.
posted by Chris Rees on March 10, 2014
It’s NOT recommended to use them directly after heavy exercise as you may be relatively dehydrated, which I believe would lead to a higher reading for % body fat. Try last thing at night before going to bed.
posted by Skye Peel on July 6, 2013
Wow; superb weblog format.. How long have you ever been running a blog for?? you make blogging glance easy.. The entire look of your web site is fantastic; as neatly as the content material! Ajax Roofing Contractors, 15-75 Bayly St. W., #323, Ajax, Ontario, L1S 7L7, Canada, 289-275-1500
posted by Jodie on July 6, 2013
Thanks! Been blogging for a while but a food and nutrition writer for years! Sign up for my newsletter to stay on top of my posts. Hope you and your family are eating healthy!
posted by Coffee Pure Cleanse Reviews on July 27, 2013
Wow! In the end I got a blog from where I know how to
actually get valuable facts regarding my study and knowledge.
posted by Get Rid Of Herpes Reviews on August 6, 2013
Wonderful blog! I found it while browsing on Yahoo News. Do you have any tips on how to
get listed in Yahoo News? I’ve been trying for a while but I never seem to get there! Appreciate it
posted by Kelly on November 12, 2013
I recently purchase a Taylor Personal Scale, it has all of the above mentioned readings with the exception of bone mass. I was curious what the healthy ranges are for a Female for the body water %. Also my scale has an Athlete Mode they consider an athlete someone who exercises 3x a week for at least 2 hours. I currently do a crossfit work out 3-4 times a week which is very intense. When should i start using this function. I am still about 30 overweight, but have lost 30 lbs. I have been doing crossfit for about 2 months, but have taken the last month off because I recently got married and went on honeymoon. Thank you
posted by Jodie on November 12, 2013
Hi Kelly,
Good for you for working out and congrats on your weight loss! Good question about the body water. I really don’t put much emphasis on this value because it fluctuates tremendously based on what we eat, hormones, temperature, etc. As for when to consider yourself an athlete, that’s your call. I have found that using a moderate to high activity works best for most people. Having said that, my son plays college football and works out well over two hours a day – intensely. So my default is to leave the Athlete Mode up to the individual.
posted by burn fat on January 9, 2014
Woah! I’m really enjoying the template/theme of this site.
It’s simple, yet effective. A lot of times it’s very difficult
to get that “perfect balance” between superb usability and visual appearance.
I must say you’ve done a great job with this. Additionally,
the blog loads extremely quick for me on Internet explorer.
Excellent Blog!
posted by Leopoldo on March 12, 2014
Way cool! Some very valid points! I appreciate you writing this post and also
the rest of the website is very good.
My website news4jax (Leopoldo)
posted by google advertising costs on April 1, 2014
I love it whenever people get together and share opinions.
Great blog, continue the good work!
posted by website on April 5, 2014
Hello There. I found your blog using msn. This is a very
well written article. I will make sure to bookmark it and return to
read more of your useful information. Thanks for the post.
I’ll definitely comeback.
posted by Christiane on April 6, 2014
Hi there, I want to subscribe for this web site to take newest updates, thus where
can i do it please help out.
posted by Jodie on April 7, 2014
Hi Christine,
Glad you like it! To subscribe to my weekly newsletter, please fill out the information on my home page under the word subscribe.
posted by Wolfgang on April 15, 2014
Can you tell us more about this? I’d like to find out some
additional information.
posted by Wesley on May 2, 2014
Greetings! Very helpful advice in this particular post!
It’s the little changes that will make the largest changes.
Thanks a lot for sharing!
posted by Elena on May 14, 2014
You could certainly see your skills within the article you write.
The arena hopes for more passionate writers like you who aren’t afraid to mention how they believe.
Always follow your heart.
posted by Kasey on June 2, 2014
Hello, I read your blog regularly. Your story-telling style
is awesome, keep doing what you’re doing!
posted by google api example on June 14, 2014
Asking questions are in fact good thing if
you are not understanding something entirely,
except this article provides nice understanding even.
posted by Gjchome.com on July 6, 2014
My family always say that I am wasting my time here at web, except I
know I am getting familiarity everyday by reading thes nice articles
or reviews.
posted by Emma Williams on August 31, 2014
Impressive Piece of writing