Measuring Your Body Fat
Key Takeaways
Muscle tissue is heavy, but is actually protective to your health. By contrast, excess fat tissue can cause damage to your health.
Your overall weight doesn’t reveal the amount of each type of tissue that you have.
Measuring your body fat can reveal how healthy your body composition is.
You can measure body fat at home using calipers (a “pinch test”) or a body fat scale. However, these methods are not generally very accurate.
Professional body composition scans provide more accuracy.
Dual-energy X-ray absorptiometry (DEXA or DXA) scans use low-dose X-rays, and are the most accurate method of measuring body composition that’s in general use.
Bioelectrical impedance (BIA) uses small electrical currents to measure body composition. It’s not quite as accurate as DEXA, but is more convenient.
Measuring your body fat
Being significantly overweight can negatively impact health in a variety of ways. This is why many people monitor their weight in order to track their health status.
However, although body weight is an easy way to measure body composition, it’s an imperfect measurement. Excess fat tissue has been found to increase the risk of many health problems and even the overall risk of death, while other types of tissue don’t carry the same risk. For example, increased muscle mass will increase body weight, but it actually protects your health rather than damaging it.
Some people who are classified as “overweight” based on their body weight are actually healthy, but have a higher than normal amount of muscle tissue. In addition, some people whose weight is classified as “normal” actually have an unhealthy amount of fat tissue, but because they also have a low amount of muscle and other tissue, their overall weight is not high.
In order to get a sense of how your body composition is impacting your overall health, it’s best to measure your body fat percentage. This will give you a better sense of whether losing weight would be likely to benefit your health, and will help you track your progress towards a healthier body composition.
While having too much body fat is dangerous, having too little actually isn’t ideal either. Although each person’s body is a little bit different, there are some target ranges that are generally considered to be healthy. These vary depending on factors like age and gender.
For women, the body fat target ranges are:
Age 20 to 39: 21% to 32%
Age 40 to 59: 23% to 33%
Age 60 and up: 24% to 35%
For men, the body fat target ranges are:
Age 20 to 39: 8% to 19%
Age 40 to 59: 11% to 21%
Age 60 and up: 13% to 24%
Keep in mind that the ideal body fat percentage for an individual can vary. It’s important to consider your body fat percentage in conjunction with other information about your health. Your doctor can help you to interpret the results of a body composition test.
Skin Fold Calipers
The least expensive way to measure body fat is using skinfold calipers. This is a small device that gently pinches both your skin and the fat just below it (known as the subcutaneous fat). This is usually done at several different locations around the body. The sites used vary, but may include the back of the arm, the area near the armpit, the area at the bottom of the shoulder blade, the chest, the abdomen, the thigh, and the area just above the hip bone. The skin fold caliper test is sometimes known as a “pinch test.”
In order to convert the measurements from a caliper test into a body fat percentage, a set of tables are used. These tables were derived from using a more accurate underwater weighing technique to determine people’s body fat percentage, then performing the caliper test on them. This means that the caliper test provides an estimate of body fat percentage, but doesn’t directly measure it. The inaccuracy may be even greater in people who are of a different race, ethnic group, or body type than those whose measurements were used to create the body fat tables.
The main advantage of skin fold calipers is that they’re inexpensive and convenient to use. However, their accuracy depends on the person using them. Slight differences in technique can make a significant difference in the results obtained. Studies have found that the error in measurements of body fat using skinfold calipers can be up to 10.9%.
Body Fat Scales
For those who would like to measure body fat at home, another option is a body fat scale, also known as a smart scale. These devices use a method known as bioelectrical impedance. This involves passing a small electrical current into your body, and then measuring how it passes through your body tissues. Because different types of tissues conduct electricity differently, this can provide a measure of body fat percentage. When undergoing this type of testing, you won’t feel the electrical current passing through your body.
Bioelectrical impedance devices are sometimes used in official settings, like laboratories, medical offices, and fitness centers, to provide measurements of body fat. There are also smaller devices that are incorporated into many bathroom scales. The scale provides your overall body weight, and uses small electrical plates under your feet to measure bioelectrical impedance and provide an estimate of your body fat percentage.
Research has found that, while a body fat scale is generally accurate at determining your body weight, it’s not very accurate at estimating your body fat percentage. This is because many factors can affect the measurements, from where your body stores fat to how hydrated you are.
Using a body fat scale may be a useful way to track changes in body fat over time at home, but it isn’t a good substitute for more detailed and accurate measurements that can be obtained through a full body composition scan.
Full Body Composition Scans
The most accurate way to determine your body fat percentage is through a full body composition scan. This measures not only your body fat percentage, but also the types of other tissues in your body, such as muscle and bone tissue.
There are a few different types of body composition scans available.
DEXA scan
Wikimedia Commons
One option is called dual-energy X-ray absorptiometry, or a DEXA scan (sometimes written as DEXA scan). This type of scan uses X-rays of two different energies. By comparing how your body reacts to the two different types of X-rays, the DEXA scan can determine the amounts of various types of tissue in the body.
In addition to the total amount of each type of tissue, a DEXA scan shows you where in your body each type of tissue is located. This gives you an idea of where your body stores fat. Because fat in different locations carries different health risks, this is useful information. Fat stored in the abdomen is generally more dangerous, while fat tissue on other parts of the body is significantly less risky to health.
To get a DEXA scan, you’ll lie on a platform for about ten minutes while the scan is performed. It does deliver a tiny amount of radiation, but this is so small that it’s only equivalent to about three hours of the normal background radiation that you’re constantly exposed to in your daily life.
BIA scan
Another option is to get a bioelectrical impedance analysis (BIA) scan. This is a similar type of technology to that used in body fat scales that you can use at home. However, the professional version is significantly more accurate.
To receive a professional-grade BIA scan, you’ll stand on a platform with metal plates, and you’ll hold handles that also contain metal plates. Through these four points of contact, the device will transmit small electrical currents into your body and will measure how they travel through your body to each of the other points. By using more electrodes, the device is able to take more accurate measurements.
Research has found that BIA is not quite as accurate as DEXA, but is still relatively accurate. It can give you an idea of where your fat is being stored overall, but will only reveal the amount of fat tissue in a few general regions, rather than the more detailed analysis of DEXA. However, BIA is more convenient than DEXA, which makes it more useful for tracking progress over time when you’ve recently started a new lifestyle program. You’ll want to make sure that you’re being scanned on the same device each time in order to use it for tracking over time, because there’s variation between different scanners.
How to get a full body composition scan
In order to get a full body composition scan, you’ll need to visit a professional who offers this type of scanning. Compared with using a body fat scale or calipers at home, this requires more of an investment of time and money, but it’s far more accurate. It also isn’t something that you’ll need to do every day. How often you choose to get a body composition scan depends on your reason for getting the scan.
If you’re actively engaged in a new lifestyle plan (such as a new exercise program), then you may want to get a body composition scan every few weeks, to track your progress. This allows you to adjust your program as necessary, and also helps to keep you motivated because you can see the effect that your efforts are having. Once you’ve settled into your new routine and reached a plateau, you may only want to scan every three to six months, to ensure that you’re staying on track with your goals.
Tracking body composition over time is one way to make sure that your lifestyle program is working well, and to keep you motivated along your weight loss journey. Clients in our NOVI Optimum Plus medical weight loss programs receive assistance from health coaches in creating and sticking to a healthy lifestyle program. They also receive weight loss medications known as GLP-1 RAs, as long as one of our physicians determines that this is a safe and effective option for that particular person.