When embarking on a journey towards body composition goals, it's tempting to rely solely on the scale. However, body weight alone doesn’t tell us enough. A more comprehensive approach involves integrating various measurement methods to gain a holistic understanding of changes in body composition, overall health, and well-being. This article explores a range of measured weight loss methods, from simple at-home techniques to sophisticated clinical assessments, providing a guide to tracking progress effectively and sustainably.
The Limitations of Body Weight as a Sole Indicator
While tracking body weight is a familiar metric, it’s crucial to understand its limitations. If your average daily body weight is decreasing over time, you’re losing body tissue. If your average body weight is increasing, you’re gaining body tissue. To most accurately track your body weight, weigh yourself daily (or at least multiple times a week), then calculate your average weekly weight to account for natural fluctuations. However, body weight alone doesn’t tell us if the change is due to fat or muscle! This is where body measurements come in.
Body weight provides a general overview, it doesn't differentiate between fat loss, muscle gain, or water retention. Muscle is denser than fat, so you may be losing fat and gaining muscle simultaneously, resulting in a stable weight or even a slight increase. This is where additional measurements and observations become invaluable.
The Power of Body Measurements
Body measurements are simple yet powerful tools. They help us determine whether specific areas of your body are increasing, decreasing, or staying the same in size. For example: If your thigh measurement grows from 23 inches to 24 inches, that area has gained tissue. If your waist measurement shrinks, it’s a strong indicator of fat loss, as the waist primarily reflects belly fat. By measuring multiple areas-such as the waist, thighs, arms, and chest-we gain a more complete picture of body composition changes. The most accurate way we can track these changes is to ensure you’re measuring as consistently as possible every 2-4 weeks.
Combining weight trends with body measurements provides a clearer picture. For instance:
Read also: Measured Weight Loss Strategies
- Body weight trends down + waist measurement trends down = overall fat loss.
- Body weight trends down + waist measurement stays the same = overall muscle loss.
- Body weight trends up + waist measurement stays the same = overall muscle gain.
- Body weight stays the same + waist measurement decreases = fat loss and muscle gain happening simultaneously.
If your goal is to change your body composition, these two data points-body weight and measurements-are invaluable.
Objective Methods for Measuring Body Fat Percentage
For a more detailed understanding of body composition, various methods can be used to measure body fat percentage. It is important to note that the most accurate measurements aren’t available at home. Here are some of the most common and reliable techniques:
1. Skinfold Calipers
Skinfold measurements have been used to estimate body fat for over 50 years (1). Skinfold calipers measure the thickness of your subcutaneous fat - the fat underneath the skin - at certain body locations. Measurements are taken at either 3 or 7 different sites on the body. The specific sites used vary in men and women.
For women, the triceps, area above the hip bone and either the thigh or abdomen are used for the 3-site measurement (2). For a 7-site measurement in women, the chest, area near the armpit and area beneath the shoulder blade are also measured.
For men, the 3 sites are the chest, abdomen and thigh, or the chest, triceps and area beneath the scapula (2). For a 7-site measurement in men, the areas near the armpit and beneath the shoulder blade are also measured.
Read also: Weight Loss Guide Andalusia, AL
Advantages: Skinfold calipers are very affordable, and measurements can be taken quickly. They can be used at home but are also portable.
Disadvantages: The method requires practice and basic anatomy knowledge. Also, some people don’t enjoy getting their fat pinched.
Availability: Calipers are affordable and easy to purchase online.
Accuracy: The skill of the person performing the skinfolds can vary, impacting the accuracy. Measurement errors can range from 3.5-5% body fat (3).
Estimating body fat percentage with skinfold calipers is affordable and relatively simple once you know how to do it. However, the accuracy depends on the skill of the person performing the assessment.
Read also: Beef jerky: A high-protein option for shedding pounds?
2. Body Circumference Measurements
Body shape varies from person to person, and the shape of your body provides information about your body fat (4). Measuring the circumference of certain body parts is a simple method of body fat estimation.
For example, the US Army uses a body fat calculation that simply requires an individual’s age, height and a few circumference measurements. For men, the circumferences of the neck and waist are used in this equation. For women, the circumference of the hips is also included (5).
Advantages: This method is easy and affordable. A flexible measuring tape and calculator are all you need. These tools can be used at home and are portable.
Disadvantages: Body circumference equations may not be accurate for all people due to differences in body shape and fat distribution.
Availability: A flexible measuring tape is easily available and very affordable.
Accuracy: The accuracy can vary widely based on your similarity to the people used to develop the equations. The error rate can be as low as 2.5-4.5% body fat, but it can also be much higher (3).
Using body circumferences to estimate body fat is quick and easy. However, the accuracy of this method can vary widely and is not considered an ideal method of measuring body fat percentage.
3. Dual-Energy X-ray Absorptiometry (DXA)
As the name implies, DXA uses X-rays of two different energies to estimate your body fat percentage (6). During a DXA scan, you lie on your back for approximately 10 minutes while an X-ray scans over you. The amount of radiation from a DXA scan is very low. It’s about the same amount you receive during three hours of your normal life (7). DXA is also used to assess bone density and provides detailed information about the bone, lean mass and fat in separate body regions (arms, legs and torso) (8).
Advantages: This method provides accurate and detailed information, including a breakdown of different body regions and bone density readings.
Disadvantages: DXAs are often unavailable to the general public, expensive when available and deliver a very small amount of radiation.
Availability: A DXA is typically only available in medical or research settings.
Accuracy: A DXA provides more consistent results than some other methods. The error rate ranges from 2.5-3.5% body fat (3).
DXA is more accurate than many other methods of assessing body fat percentage. However, it’s often unavailable to the general population, fairly expensive and not feasible for regular testing.
4. Hydrostatic Weighing
This method, also known as underwater weighing or hydrodensitometry, estimates your body composition based on its density (9). This technique weighs you while submerged under water after exhaling as much air as possible from your lungs. You are also weighed while you are on dry land, and the amount of air left in your lungs after you exhale is estimated or measured. All of this information is entered into equations to determine the density of your body. Your body’s density is then used to predict your body fat percentage.
Advantages: It’s accurate and relatively quick.
Disadvantages: It’s difficult or impossible for some individuals to be fully submerged under water. The method requires breathing out as much air as possible, then holding your breath underwater.
Availability: Hydrostatic weighing is typically only available at universities, medical settings or certain fitness facilities.
Accuracy: When testing is performed perfectly, the error of this device can be as low as 2% body fat (3, 10).
Hydrostatic weighing is an accurate way to assess your body fat. However, it’s only available at certain facilities and involves holding your breath while being completely submerged in water.
5. Air Displacement Plethysmography (Bod Pod)
Similar to hydrostatic weighing, air displacement plethysmography (ADP) estimates your body fat percentage based on the density of your body (9). However, ADP uses air instead of water. The relationship between the volume and pressure of air allows this device to predict the density of your body (11). You sit inside an egg-shaped chamber for several minutes while the pressure of the air inside the chamber is altered. To obtain accurate measurements, you need to wear skin-tight clothing or a bathing suit during testing.
Advantages: The method is accurate and relatively quick, and it does not require being submerged in water.
Disadvantages: ADP has limited availability and can be expensive.
Availability: ADP is typically only available at universities, medical settings or certain fitness facilities.
Accuracy: The accuracy is very good, with an error rate of 2-4% body fat (3).
The Bod Pod is the main ADP device currently used. It predicts your body fat with air rather than water. It has good accuracy, but it’s typically only available at certain medical, research or fitness facilities.
6. Bioelectrical Impedance Analysis (BIA)
BIA devices detect how your body responds to small electrical currents. This is done by placing electrodes on your skin. Some electrodes send currents into your body, while others receive the signal after it has passed through your body tissues. Electrical currents move through muscle easier than fat due to the higher water content of muscle (12). The BIA device automatically enters your body’s response to the electrical currents into an equation that predicts your body composition. There are many different BIA devices that vary widely in cost, complexity and accuracy.
Advantages: BIA is quick and easy, and many devices can be purchased by consumers.
Disadvantages: The accuracy varies widely and can be greatly affected by food and fluid intake.
Availability: While many units are available to consumers, these are often less accurate than the expensive devices used in medical or research settings.
Accuracy: Accuracy varies, with an error rate that ranges from 3.8-5% body fat but may be higher or lower depending on the device used (3, 13).
BIA devices work by sending small electrical currents through your body to see how easily they travel through your tissues. Many different devices are available, although advanced devices produce more accurate results.
7. Bioimpedance Spectroscopy (BIS)
BIS is similar to BIA in that both methods measure the body’s response to small electrical currents. BIS and BIA devices look similar but use different technology. BIS uses a much larger number of electrical currents than BIA, in addition to high and low frequencies, to mathematically predict your amount of body fluid (14). BIS also analyzes the information differently, and some researchers believe that BIS is more accurate than BIA (14, 15). However, similar to BIA, BIS uses the body fluid information it gathers to predict your body composition based on equations (15). The accuracy of both of these methods depends on how similar you are to the people for whom these equations were developed (12).
Advantages: BIS is quick and easy.
Disadvantages: Unlike BIA, consumer-grade BIS devices are not currently available.
Availability: BIS is typically only available at universities, medical settings or certain fitness facilities.
Accuracy: BIS is more accurate than consumer-grade BIA devices but has a similar error rate to more advanced BIA models (3-5% fat) (3, 16).