Comparing Body Composition Techniques – DexaFit, Amazon Halo, and Withings Body+Scale

One of the most common devices used to track wellness at home is a standard scale. These days a simple and reliable scale can be picked up for around $10 online. But weight is only a symptom of other indicators when tracking wellness. Of course there are deluxe versions of scales that run well over $100. They try to provide more insights than just a single weight measurement. Most commonly this is some type of body composition reading. To see the comparison of three popular body composition and BMI ratings, scroll to the end of the article.

Body composition is, generally, a measurement that compares how much of your body’s mass is in muscle compared to how much is fat. There is of course a lower limit, since you need some fat, and no matter what you will have a percentage of your mass in bone mass, but generally speaker a higher ratio of muscle to fat is better.

Beyond the scale the same body composition measurement is gathered via other tools. Some of them use simple imagery, like the Amazon Halo app, while others like the Dexascan use internal body scans to measure the materials directly. Each measurement type has its benefits, differs in how easy they are to get access to, and varies slightly on the output and reliability.

Withings Body+ Scale

The scale covered elsewhere on this site, along with its companion blood pressure cuff, is the Withings Body+. Using an unfeelable small electrical current it measures the impedance in your lower body and uses that to calculate body fat as a way to tell body composition.
Withings body+ body scan

If you want the full rundown of the Withings scale, check our our review of the Body+ Scale. The great part of this is that it is easy to take a reading on a daily basis. There is no need to get fully undressed, setup a camera and take pictures, or pay and visit a clinic to get a reading. You will need to have your shoes off, since the signal requires skin contact, but beyond that the reading is done in only a few seconds and is generated automatically when you step on the scale.

Is Amazon Halo Body Fat Scan Accurate?

Update April 2023: Amazon has stated that they will no longer support Amazon Halo. This adds it to the list of products they have tried and then abandoned over the years (like the Fire Phone, Cloud Cam, Dash Buttons, and more) . Starting in August 2023 the app will no longer function, rendering the Halo Band and Halo View as useless, expensive, visually unappealing bracelets. As a multi-year user this is disappointing. We are leaving these reviews here to share the things that did work about Halo, despite the annoying subscription business model and lack of features compared to competitors.

The Amazon Halo is a competitor to a Fitbit and the Whoop band. The wrist worn step tracker, the Halo band, is one component of the Amazon Halo service though. The other part, for now, is an app that tracks stats. In it you can setup a scan using just your smartphone camera. Prop a phone up, stand back, and follow its prompts to get photos of you from multiple angles and it’ll stitch the images together into a full body scan. Using some proprietary formula it then spits out a body fat percentage.

body composition from amazon halo

Halo’s body fat accuracy seems to align to most other ground truths. It does a better job of predicting fat than many of the scales do, so do not be scared if the numbers it reflects are different than your smart scale. As with any of these the body composition reading should be compared only from the same source so that it is known to be calculated in the same way. An odd, but useful, benefit of the method of measurement Amazon Halo conducts is that it provides a useful image.

While before and after pictures are common in marketing and promotion of popular fitness tracking and wellness plans, it is an area that many people do not do. Whether that is because it can be intimidating to take a picture or simple laziness, images seem to be a barrier of tracking. If you do take them though they can be an amazing way to reveal changes that were otherwise hidden in numbers.

Dexafit Body Scanning – Dexascans for Body Composition

The most accurate way to get body composition is some form of lab visit. Commonly wellness centers, university labs, and some clinics, will have a submersible tank for measurement. Now though you can also get a scan with a machine the measures via a non invasive methods.

Dexafit is one of the most common of these. It has the benefit of better accounting for significant hidden muscle, and body types that carry more weight in certain areas since it measures each area independently.
Body composition with dexascan

Body composition trend
The scans here suggest that Amazon Halo is closer to accurate than a smart scale. That’s if you trust the scan is the most accurate. To be fair the scale varies slightly each time you step on it, but generally is consistent. That means if you are using it to track progress it’s pretty good, even if the absolute number is somewhat off of others. It also means if you’re used to stepping on a smart scale, be prepared to see a higher body fat measurement when you use a different technique.

To summarize how each of these readings stack up. How accurate are the body fat readings from smart scales and body scans? Across the Amazon halo app, a Withings scale and health mate reading, and the dexafit body scan the results within a week of each other are:

  • Amazon Halo Body Fat – 26.1%
  • Withings Body+ Smart Scale – 19.1%
  • Dexafit Body Composition Scan – 24.3%

keep in mind these readings are for someone who is 6 feet, 2.5 inches tall and weighing about 186 pounds. That puts the BMI at around 23.6 which lands in the healthy range according to the CDC BMI calculator.