I’ve talked about this before. Body weight scales aren’t really the best tool for measuring your ketogenic diet progress. But, they’re better than nothing and my opinion about this has started to change recently. Some of the newer scales are equipped with features that can give you details on your body composition, not just your weight. They’re able to calculate body fat percentage with fairly good accuracy. Without this, you’re viewing your weight blindly.
The new scales are equipped with a technology called Bioelectrical Impedance Analysis (BIA). BIA works by sending very weak electrical impulses from one end of your body to another. Normally, this is your hands or feet. BIA measures the resistance that happens as the current passes through you. In the case of a home scale, there are metal electrodes you stand on that send a signal through your feet.
BIA scales use the water content of your body to determine your total fat and lean mass. The more water you have in your body, the less electrical resistance you have. Lean tissue is anywhere from 20–75% water. Muscle, in particular, is around 70–75% water. On the other hand, fat is only 10% water. BIA uses these percentages to calculate your body composition.
BIA scales aren’t the only way to measure body fat. DEXA is the gold standard when it comes to measuring body composition. If you are an athlete or someone that is taking your weight loss journey very seriously, I think you’ll find your DEXA results helpful. The negative is that they are expensive and expose you to a small amount of radiation.
The traditional method would be with using a caliper. The downside with skin calipers is that you need another person to do the test, and it needs to be done consistently. It’s pretty easy to mess this up.
For the average person, I think BIA scales are the absolute easiest way to track your progress.
Reasons to Use a BIA Scale for Keto
- Progress tracking is important. It gives us assurance and confidence that we are doing the right thing.
- Bluetooth scales sync with Apple Health, Google Fit, and Fitbit. No hassle whatsoever.
- Weight fluctuations with keto are very common.
- BIA scales calculate body fat percentage.
- BIA helps determine how much water weight you are losing. (around 5-10 lbs on average)
Accuracy of BIA Scales
Studies seem to suggest that BIA is accurate for adults but not as accurate for children. As a result, some of the scales do not measure body fat for people under 18. [*]
In my own testing, I’ve found BIA to be accurate enough for measuring daily progress. I actually compared my results to a recent DEXA scan. Body fat percentage was very close (less than 1 percent off). A significant difference was with the Bone Mineral Content (BMC) reading. My Renpho scale was off by –1.0 lb.
Note: If you are pregnant or have a pacemaker, your results may be inaccurate. Other embedded electronics could cause problems as well.
Ways to Increase Accuracy for your Scale
- Step on the scale first thing in the morning after you pee.
- Dehydration can also cause inaccuracies.
- Avoid eating or drinking large amounts before your reading.
- Be as consistent as possible.
If you are in the market for a BIA scale, I have two scales below that will work well for tracking your progress. These BIA scales will automatically upload your results to Apple Health and Google Fit.
Disclaimer – Affiliate links below. I don’t recommend anything that I haven’t tried myself or haven’t done extensive research on. I just appreciate you being here.
Renpho Bluetooth Body Fat Scale
Personally, I own the Renpho scale. For the price, it is going to be hard to beat. In my experience, it is accurate, easy to set up, and aesthetically pleasing. Overall, this a great scale to use for tracking progress on keto.
- Apple Health, Google Fit, and Fitbit sync compatible
- App with both Android and IOS support
- Measurements tracked over time. (BF%, BMI, BMR, Weight, BMC, Water)
- One Year Warranty
- The app does not have the greatest ratings.
- Some measurements can be a few percentage points off such as BMC.
Yunmai Premium Smart Scale
The Yunmai scale has a few more features than the Renpho. If you have a little higher budget, I would go with this model.
- Apple Health, Google Fit, and Fitbit sync compatible.
- Can see your Body Fat Percentage directly on the scale.
- Multiple measurements recorded over time.
- Accommodates up to 16 different people via the dedicated App.
- Bright Display that is Easy to Read
- The app does not have the greatest ratings.
- If the user is under 18, the scale may not calculate BF%.
- Customer support has mixed reviews.
Conclusion – BIA Scales and Keto
At the end of the day, using a scale with bioelectrical impedance analysis technology is the easiest and cheapest way to get your body composition stats. Is it perfect? No. Is it the most accurate option? No. However, for measuring daily progress, BIA scales are simply your best option. I’ve been using mine for about a week now and have been impressed with the data it is gathering.