Forget Fitness Trackers — Here’s Why a DEXA Scan is the Go-To for a Full Body Assessment

With the advancements in consumer health technology, many people have access to fitness and health trackers, smart scales, and the like, but the reality is, they’re not very accurate (sorry, but it’s true). So, how do you get a full, accurate, and comprehensive picture of your overall health? That’s where a DEXA scan comes in. DEXA (Dual Energy X-ray Absorptiometry) is a safe and incredibly accurate technology that goes beyond the bathroom scale to measure your precise body composition — including muscle mass, fat distribution, and bone density.

This health screening can empower you with a comprehensive understanding of your body and actionable insights to optimise your wellness journey. Professional athletes have long known the benefits of this powerful body scan, but more recently, the test has been championed by longevity experts like Peter Attia because of the extensive feedback the scan provides. Now everyday athletes and average Jo-annes are quickly joining the club to use the metrics of this diagnostic imaging to guide their health and wellness journeys.

To get to grips with this fascinating technology, I booked a DEXA scan at SCP Radiology TygerValley Mammography Centre. The results were fascinating, to say the least, and the results of the scan have given me incredible insight into my overall health. With branches across the Western Cape, SCP Radiology has been providing medical imaging services in the Western Cape since 1950 and is a trusted independent radiology practice.

Weighing up your muscle-to-fat ratio using radiology

For ages, Body Mass Index (BMI) has been used as a measure of health, but it is a fairly crude measure of body composition derived solely from the mass and height of an individual. While BMI is useful for examining trends in the population level when other measurements are not available, this metric is limited when applied to individuals because it does not account for variations in muscle mass, bone density, or fat distribution.

In contrast, DEXA provides a much more detailed breakdown of body composition. The machine uses low-dose X-rays to measure how two different types of energy pass through your body, ultimately providing an estimate of how the total mass of the body is divided across three components: lean tissue (muscle and organs), fat mass, and bone mineral content. These accurate metrics of bone mineral density, body fat percentage, total lean mass, total fat mass, BMI, and body composition in specific regions of the body go far beyond the simplicity of BMI, giving you and your healthcare provider a clearer picture of where your health is at.

Dr Anne-Marie du Plessis from SCP Radiology says: “The reason we recommend a DEXA scan is it’s a quick method of calculation often used for measuring body fat and results differentiate between subcutaneous and visceral fat. The Body Mass Index (BMI) is a measurement of relative body weight, not body composition, and is calculated by dividing a person’s weight by the square of their height. However, lean mass weighs far more than fat, which means many adolescent athletes are incorrectly classified as obese based on traditional BMI measurements. That said, a BMI is useful as a quick and easy screening tool, especially for large populations or when advanced equipment is not available.”

Bottom line: Body composition is key, evaluating your health is not just about weight; your muscle, fat, and bone density all impact your health and fitness goals. It’s true for many people that data empowers action. A DEXA scan can help reveal the details you need to optimise your diet, workouts, and overall health to prolong your life and feel better in the short and long term.

What is a DEXA scan & how does it work?

There are many ways of finding out your body composition but none are as effective as a body composition scan. The scan generates a ‘fat shadow’ image showing the fat distribution in the abdomen, arms, legs and pelvis. Not only does a DEXA scan provide fast results, but it is also widely accepted as the gold standard for obtaining a comprehensive analysis of body composition.

DEXA scans use two low-dose X-ray beams that pass through the body at different energy levels. By measuring the absorption of each beam by the body tissues, DEXA can differentiate between bone mineral content, fat tissue, and lean tissue (muscles, organs, etc.). The results are highly precise and provide a detailed breakdown of body composition.

The DEXA report is particularly accurate and detailed because the scan is able to differentiate between fat mass and lean muscle mass. This is crucial for understanding your true health and fitness levels. One of the most important findings is your visceral fat measurements.

What is visceral fat?

As a type of body fat stored within the abdominal cavity, visceral fat is unlike subcutaneous fat which lies just beneath the skin. Visceral fat surrounds vital organs like the liver, pancreas and intestines. It is considered particularly harmful because it is metabolically active, meaning it releases inflammatory markers and hormones that can influence your body’s function and increase the risk of chronic diseases like heart disease and diabetes.

If you know you have high visceral fat, you can focus on a combination of cardiovascular and resistance training, along with dietary changes to reduce it. Ways to reduce your visceral fat include cutting down on sugars and refined foods, limiting alcohol consumption, increasing fibre and protein, and regular exercise (including cardio workouts and strength training). Stress can also lead to weight gain, especially around the abdomen, as can too little sleep.

“The exponential increase in the prevalence of lifestyle diseases means DEXA body composition scans have a pivotal role to play in determining your health risks, assessing fitness, tracking changes in body composition and guiding nutrition and exercise programmes,” adds Dr du Plessis.

Benefits of a DEXA scan

In addition to knowing your visceral fat measurements, there are many other health and wellness benefits to having a DEXA scan. The scan can serve as a great starting point for a new health and fitness journey or even as a recalibration during an ongoing wellness journey to help empower you to achieve your fitness goals.

Whether you want to lose fat, gain muscle or maintain your weight, a body composition scan allows you to see changes that might not be reflected on the scale. This is particularly important if you’re gaining muscle while losing fat, as your weight might stay the same but your body composition will improve.

For athletes, understanding body composition is key to optimising performance. The right balance of muscle and fat can enhance strength, speed and endurance, while also reducing the risk of injury. Any professional or everyday athlete can benefit greatly from the wealth of knowledge obtained about body composition from a DEXA scan.

The scan results can also help with motivation and accountability on your health journey. Seeing concrete numbers and changes in body composition can be a powerful motivator. It provides a clear picture of how your efforts are paying off, beyond what a regular scale might show, encouraging you to keep going and make adjustments where needed.

What to expect from your DEXA scan experience

While it may sound like a complicated procedure, the DEXA scan experience is very quick, painless, and simple. You’ll be in and out of SCP before you know it. But, that doesn’t mean you’ll want to leave; unlike most doctor’s rooms, the SCP practice offices feel more like a luxury spa than a medical practice. SCP makes the experience even more pleasurable with a beautiful, warm and inviting space and friendly radiographers to guide you through the process.

Before the scan, patients are invited to relax with a coffee in the lounge waiting area. From the waiting area, you’ll be introduced to your assigned radiographer and escorted to the private changing facilities should you need to change into a gown for the scan.

The scan process itself is very quick and easy. “In short, you lie on a table and the machine scans your whole body to assess your body composition,” explains Dr Du Plessis. “The scan takes about seven minutes and the radiation dose is almost nothing – it’s equivalent to 24 hours of background radiation at sea level. A report is then generated indicating the amount of muscle and fat in your body.”

You’ll be required to keep still during the scan, as any movement can distort your results but it’s so short you’ll hardly notice. I’d recommend scanning in the morning on an empty stomach and being well-hydrated. If you’re going for a follow-up scan a few months later (every 6 months to a year is recommended depending on your goals) then it’s advised to scan under the same conditions. Try wearing clothing that contains no metal (zips, buttons, underwire bra, etc) if you’d prefer not to wear a hospital gown for the scan.

Your DEXA scan report

Every patient at SCP Radiology receives a comprehensive radiologist’s report a few days after the scan. The report can be sent to your referring healthcare provider (whether that be your doctor, physiotherapist, surgeon, etc), as well as directly to you.

The report breaks down your Total Body Composition (including the overall percentages and absolute amounts of body fat, lean tissue mass, and bone mineral content); Fat Mass (the total amount of body fat measured in grams or kilograms and its percentage relative to total body weight); Lean Mass (the total weight of lean tissue, which includes muscles, organs, and water, usually reported in grams or kilograms); Bone Mineral Content (BMC) (the weight of the minerals in bones, which helps assess bone health alongside body composition); and Regional Analysis (body composition measurements for different regions of the body to help identify specific areas with higher fat deposition or lean mass),

In addition to including your individual measurements, your DEXA scan report also includes percentile comparisons based on your age, and sex. These percentages indicate how the patient’s body composition compares to a reference population. Reference standards percentiles are based on population studies and reference data to help healthcare providers determine whether a person’s body composition is within a healthy range.

The report compiled by an SCP Radiologist is easy to understand and is a great tool to use when analysing your overall health with your healthcare provider. For me, it was a great jumping-off point for recalibrating my health and fitness journey. While I’ve been consistent with exercise and a healthy diet over the years, the report was able to shine a light on areas of my health that may need further tweaking and exploration with my doctors and physiotherapist.

Having this scan has proven to be beyond invaluable in helping me determine what I need to focus on to achieve my health and fitness goals. If you’re interested in taking a more focused approach to health and training, then this scan is the place to start. The DEXA scan is a wonderful tool if you’re looking for specific data to help you fine-tune your exercise and training programme. Playing sport 2-3 times a week, along with gym training, I’m always looking to ensure my body stays injury-free and tackle any muscle deficiencies that may be creeping in.

Getting the report showed my lean muscle mass across my entire body, with a detailed breakdown of every limb. Seeing whether my right and left leg were balanced, where I was holding onto any fat, and my skeletal health was been incredibly important. The scan has helped me adjust some nutrition elements as well as focus on other muscle areas in the gym that I wouldn’t have known about otherwise.

I would highly recommend a DEXA scan to any everyday athlete, especially runners and endurance athletes. I plan on tracking my progress with another DEXA scan in 6 months to gauge the effectiveness of the adjustments that I’ve made to my lifestyle and training.

Book a DEXA scan in South Africa

To book your DEXA scan, visit the SCP Radiology website to find a practice near you. To make booking even easier, you can submit a quick appointment request online for you, a loved one, or a patient in your care.