DEXA scans are a popular and convenient way to measure body composition. However, some folks may not have a facility with one nearby, can’t afford a scan, or don’t want radiation exposure. Regardless of the reason, there are DEXA scan alternatives for body fat. In the article below I will address the three most common alternatives to a DEXA scan.
3 DEXA Scan Alternatives for Body Fat
There are 3 popular alternative methods people use to measure body fat besides a DEXA scan. These are skinfold calipers, Bioelectrical Impedance Analysis (BIA), and Hydrostatic Weighing. Each has its pros and cons which we will discuss in more depth.
Skinfold Calipers for Taking Body Fat Measurements
Skinfold calipers are the most popular DEXA scan alternative and are often used in research studies. The biggest advantage of skinfold calipers is that they are relatively inexpensive and easy to use at home with little practice. You can even buy them on Amazon for around $10. There are fancier digital ones, that cost around $25.
The downside to skinfold calipers is that they are ballpark measurements and can be affected by the person taking the measurement (i.e., caliper technique). You can also misinterpret the results by misreading the chart based on the measurement you took.
Skinfold Calipers vs DEXA Scan Accuracy for Measuring Body Fat
A study published in the Journal of Exercise Physiology compared DEXA scans and skinfold caliper measurements in 160 young adults. They found that DEXA was more accurate than skinfold measurements for estimating body fat.
The authors concluded, “for prediction of percent body fat in young adults, DEXA is a more precise method than skinfold thickness measurements.”
So, if you want the most accurate estimate of your body fat possible, DEXA is the way to go. But, if you’re on a budget or just want a quick estimate, skinfold calipers are a decent alternative.
I have been using skinfold calipers for a few years. I found that the results, while a bit more broad range, is within a +/- 1% of what my DEXA scan for body fat told me.
Cost Comparison of Skinfold Calipers vs DEXA Scan
Skinfold Calipers are the most inexpensive way to measure body fat. The average DEXA body fat scan costs between $50 and $100. You can get a cheap pair of skinfold calipers on Amazon for $10.
Bioelectrical Impedance Analysis (BIA) for Measuring Body Fat
Bioelectrical Impedance Analysis (BIA) is another popular method used to estimate body composition. It works by sending a small electrical current through your body and measuring resistance. The assumption is that lean tissue has a higher water content than fat tissue and, therefore, conducts electricity better.
The biggest advantage of BIA is that it is quick and easy. You can find BIA scales for under $50 on Amazon. And, many gyms have them too. You can find them in the form of body weight scales you stand on or in the form of hand-held devices.
The best BIAs use a combination of both something you stand on and something you hold. When you use a BIA that is just one or the other the reading is significantly less accurate.
BIA vs DEXA Scan Accuracy for Measuring Body Fat
There are a few studies that have looked at the accuracy of BIA vs DEXA for measuring body fat.
One study, published in The Journal of Obesity Society, found that “for most populations and devices, BIA is as accurate as DEXA for estimating body fat percentage.”
Another study, published in the Journal of Sports Science and Medicine, found that BIA was less accurate than DEXA for estimating body fat in elite athletes.
The bottom line is that BIA is a quick and easy way to get an estimate of your body fat. However, it is not as accurate as DEXA. In my experience, the BIA results can often be off by as much as 10% when compared to my DEXA scan results and my skinfold calipers.
Cost Comparison of a BIA vs DEXA Scan
BIAs can be cheaper than a DEXA scan for body fat, but it depends on what you buy. There are scales with BIA features for under $50 on Amazon, but there are also more advanced ones over $100. With that range, it is about the same as the cost of a DEXA scan which on average costs $50 to $100 depending on where you go for the test.
Hydrostatic Weighing for Measuring Body Fat
Hydrostatic weighing, also known as underwater weighing, is the gold standard for measuring body density. It is often used in research studies because it is considered to be the most accurate method for estimating body fat.
The principle behind hydrostatic weighing is that your body weight will change when you are submerged in water due to the displaced water. The amount of water displaced is equal to your body volume. So, by knowing your body weight both in and out of the water and the density of the water, you can calculate your body fat percentage.
The biggest advantage of hydrostatic weighing is that it is very accurate. It is also not that expensive.
The biggest disadvantage of hydrostatic weighing is that it is not widely available, you need to submerge four to five times, and be undressed. You will need to find a facility that has the proper equipment and trained personnel. And, it can be time-consuming as the whole process can take up to an hour.
Hydrostatic Weighing vs DEXA Scan Accuracy for Measuring Body Fat
There are a few studies that have looked at the accuracy of hydrostatic weighing vs DEXA for measuring body fat.
One study, published in The Journal of Obesity Society, found that “hydrostatic weighing is the most accurate method for estimating body fat percentage.”
Another study, published in the Journal of Applied Physiology, found that hydrostatic weighing was more accurate than DEXA for estimating body fat and is accurate between 1.8 and 2.8% of your actual body fat.
Cost Comparison of a Hydrostatic Weighing vs a DEXA Scan
There are college universities that administer them for $50 on your first visit and $35 for each subsequent visit. Which is cheaper than what a DEXA scan for body composition costs. In my experience, my first DEXA scan for body composition cost $107 and $87 for each scan after.
How Accurate is a DEXA Scan for Body Composition
Know that we know the alternatives, it’s a good idea to understand how accurate a DEXA scan is. According to some studies the error rate on a DEXA scan for body fat is between 4 and 10%. While that may seem like a lot, the benefit is that it only takes 15 minutes, you can stay fully clothed, and it’s much more accurate than BIA’s or skinfold calipers.
What I like to do is get a DEXA scan for body composition quarterly and then measure my body fat with skin calipers every two weeks. I generally find that the skinfold calipers get me within a 1% of what the DEXA scan says. What’s nice about the DEXA is it gives more pinpoint accuracy. For example, my skinfold calipers tell me I am in the range of 15.9%, but my DEXA scan says I am at 15.4%.
DEXA scans Give You the Added Benefit of Additional Data
The one thing the DEXA Scan Alternatives for Measuring Body Fat doesn’t give you is additional data. For example, DEXA shows you how your body fat and lean mass are distributed throughout your body. You can use the output data to see muscle imbalances between your left and right arms and legs. You can also see where your body stores its fat via the composition chart.
3 DEXA Scan Alternatives for Measuring Body Fat – Bottom Line
The DEXA scan is the one of most accurate ways to measure your body fat, Hydrostatic weighing is technically more accurate, but less convenient. However, some alternatives can give you a close estimation. If you don’t have access to a DEXA scan, I recommend using skinfold calipers or BIA. And, if you want the most accurate measurement possible, hydrostatic weighing is the way to go.