Body Composition Scan in Australia, Test Your Body Fat Today

How is body composition assessment done?

Body composition refers to the structures that comprise your body, including fat, muscles, bones, tendons, ligaments, organs, and water.

Body composition assessment helps you understand how your total body mass is composed of the relative proportions of fat mass and fat-free mass. It is interesting to note that fat-free mass is composed of muscles, bones, organs, ligaments, tendons, and water. The various methods for measuring body composition include skinfolds (SKF), digital image analysis, air displacement plethysmography (ADP), and sophisticated imaging techniques such as Dual-Energy X-ray Absorptiometry (DEXA), Computed Tomography (CT), and Magnetic Resonance Imaging (MRI). 

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What are the uses of DEXA in body fat measurement?

DEXA is used for assessing body composition and bone density. The uses of DEXA include:

• To check obesity or adiposity in your body. Increased accumulation of fat increases the risk of chronic diseases such as high blood pressure, heart disease, stroke, and cancer
• Assess your nutritional status and dietary habits to make changes in your lifestyle
• Evaluate weight loss in people undergoing bariatric surgery or surgery to remove excess fat, or those on medications, diets, or weight loss therapies expected to cause a considerable weight loss
• Measure body fat and fat-free mass if you have a significant decrease in muscle strength or poor physical function
• HIV-positive patients are at increased risk of muscle wasting, and it is vital to evaluate fat distribution when using antiretroviral therapy 

How does a body composition scan work?

DEXA is an imaging technique that uses X-rays and has a three-compartment model to measure fat mass, fat-free mass, and bone mineral content. The rate of radiation absorption by various materials in the body at two distinct energy levels is the chief principle of DEXA. 

In simple terms, photons, or energy particles in X-rays with higher energy, have lower attenuation, or a decrease in energy. This permits photons to pass freely through low-density materials, such as soft tissue in comparison to high-density materials like bone. The difference between the two energy peaks of the X-ray depends on the type of tissue encountered. 

How is a DEXA scan done?

A body composition scan with DEXA is an outpatient procedure, which means you won’t have to stay in the hospital. Here’s how the DEXA scan works:

• You’ll lie down on a special X-ray table
• A radiographer will help position your body, sometimes using foam blocks to hold your body in the correct position
• The technician will pass the DEXA scanning arm over your body which takes pictures of your body areas. The areas of interest consist of both sides of your trunk, arms and legs

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How do you prepare for a body composition scan?

Simple preparation is required for a DEXA scan:

• Stay well-hydrated and avoid eating for at least three hours before the procedure
• Reduce the amount of metal that you may be wearing.  Watches, zippers, jewellery and underwires should be taken off before the scan.  It is ok to keep wearing a piece of jewellery if it is difficult to remove or is implanted inside you
• Lightweight clothing is ideal.  Avoid heavy sweatshirts and jeans
• Avoid procedures that involve any contrast dye for at least 2 weeks before your scan  

When is the body composition scan not indicated?

A body composition scan with DEXA is not indicated in the following situations:

• Pregnancy: The amount of radiation is minimal for adults; however, it can harm the growing fetus
• Adolescents: Adolescents under 18 years are still in the growing phase of life, so they should avoid exposure to radiation
• Overweight: Individuals above 204kg may be above the weight capacity of the machine
• Eating disorders: People with a history of body image concerns or eating disorders

What are the potential risks of DEXA body composition scans?

DEXA body composition scans use very low-dose X-rays—typically less than a tenth of a standard chest X-ray—to map your fat, muscle and bone. This minimal radiation exposure is universally regarded as safe for most adults and carries virtually no measurable long-term risk. No contrast agents, needles or injections are involved, so there’s zero chance of allergic reaction or injection-site complications.

The chief safety consideration is pregnancy: even low-level X-rays can pose a risk to a developing fetus. If you are pregnant, think you might be, or breast-feeding, you should always inform your doctor and the radiographer before your appointment. Beyond that, the only procedural limitation is mechanical—if you exceed the scanner’s weight capacity, the exam may be incomplete or unavailable, but it does not introduce additional health hazards.

Because DEXA does not require sedation or prolonged positioning, there’s no risk of dizziness, blood pressure shifts or recovery-room monitoring. And once the scan is complete, all X-ray beams have already dissipated—there’s no lingering radiation in your body.

In rare cases, you may be asked to repeat part of the scan if slight movement blurs the images; this adds a negligible extra dose but remains well within safety guidelines. Overall, the benefits, detailed insight into your body composition that can guide nutrition, training or medical care, far outweigh the minimal risks associated with DEXA.

What happens after a DEXA body composition scan?

Once your scan finishes, you can stand up and return to your normal routine immediately—there’s no downtime, no dietary restrictions and no special aftercare needed. You don’t need to rest, drink extra fluids or avoid any activities unless your healthcare provider advises otherwise.

Your scan images and report are automatically sent to your referring practitioner, typically within a week to ten days. You’ll also be able to log in to the imaging centre’s secure patient portal or mobile app to view your full body composition breakdown—total body fat percentage, regional fat and lean mass, and bone density—alongside graphical trend lines if you’ve had prior scans.

At your next appointment, your doctor or allied health professional will walk you through the results in plain English, explaining what your numbers mean for your health, fitness or bone strength goals. They may recommend adjustments to your diet or exercise plan, refer you to a specialist, or schedule a follow-up scan in three to six months to track changes.

If any unexpected findings arise—such as a drop in bone density or an unusual fat distribution—your practitioner will outline next steps, which could include additional tests or targeted therapies. Otherwise, you simply integrate this rich data into your personalised health or performance strategy and carry on.

Interpretation of results

After the body fat test,  you will have a consultation with your doctor or healthcare provider who ordered the scan. They will review a comprehensive explanation of your body composition results. They will provide personalised recommendations tailored to your specific goals, whether you are focused on reducing fat, or building muscle. You will also receive a comprehensive report for your records, and your results can be compared to monitor your progress by repeat testing in 3-6 months. The main parameters of body composition include:

Total Body Fat Percentage (%BF)

%BF is the percentage of the body that is composed of fat. This will vary depending on the amount of fat and lean mass present in your body. The normal values for females are 21%-33%, and for males are 7%-20%.

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BMI is calculated using your weight and height (your weight divided by your height squared). BMI does not provide information about the location of fat, muscle mass, or bone mass, which are all contributing factors to your weight. Your age, gender, race, and ethnicity can also affect BMI. The limitations of BMI calculation include:

• Women, on average, have more body fat and less muscle mass than men
• A high BMI is noted in trained athletes due to increased muscle mass, but relatively little body fat
• Older adults carry more body fat than younger adults. Higher BMI in the elderly population with optimal diet and exercise is associated with a lowered risk of osteoporosis 
• While BMI and weight tend to decline in the elderly, visceral abdominal fat may continue to increase
• Both men and women with larger body frames may have a higher weight from greater or heavier bone mass, than fat mass

Visceral Adipose Tissue (VAT)

VAT is a component of your total body fat that contributes to hormone production. It measures the amount of internal abdominal fat around the organs, which is referred to as visceral fat.  It differs from the subcutaneous fat, which lies beneath the skin.  An increase in VAT is associated with an increased risk of heart and metabolic diseases. 

VAT values for males:

20-29 years old:

• Optimal: <45g
• Suboptimal: 45-343g
• High Risk: >343g

30-34 years old:

• Optimal: <119g
• Suboptimal: 119-612g
• High Risk: >612g

35-39 years old:

• Optimal: <209
• Suboptimal: 209-731g
• High Risk: >731g

40-44 years old:

• Optimal: <284g
• Suboptimal: 284-970g
• High Risk: >970g

45-49 years old:

• Optimal: <388g
• Suboptimal: 388-1164g
• High Risk: >1164g

50-54 years old:

• Optimal: <537g
• Suboptimal: 537-1403g
• High Risk: >1403g

55-59 years old:

• Optimal: <612g
• Suboptimal: 612-1537g
• High Risk: >1537g

60-64 years old:

• Optimal: <761g
• Suboptimal: 761-1731g
• High Risk: >1731g

65-69 years old:

• Optimal: <851g
• Suboptimal: 851-1881g
• High Risk: >1881g

70-80 years old:

• Optimal: <970g
• Suboptimal: 970-2090g
• High Risk: >2090g

VAT Values for females:

20-29 years old:

• Optimal: <30g
• Suboptimal: 30-179g
• High Risk: >179g

30-34 years old:

• Optimal: <30g
• Suboptimal: 30-224g
• High Risk: >224g

35-39 years old:

• Optimal: <75
• Suboptimal: 75-269g
• High Risk: >269g

40-44 years old:

• Optimal: <90g
• Suboptimal: 90-388g
• High Risk: >388g

45-49 years old:

• Optimal: <104g
• Suboptimal: 104-448g
• High Risk: >448g

50-54 years old:

• Optimal: <149g
• Suboptimal: 149-612g
• High Risk: >612g

55-59 years old:

• Optimal: <224g
• Suboptimal: 224-746g
• High Risk: >746g

60-64 years old:

• Optimal: <299g
• Suboptimal: 299-836g
• High Risk: >836g

65-69 years old:

• Optimal: <358g
• Suboptimal: 358-955g
• High Risk: >955g

70-80 years old:

• Optimal: <448g
• Suboptimal: 448-1074g
• High Risk: >1074g

Outcome of out-of-range body composition scan values

High values on the body composition scan

Higher values in body fat percentage and visceral adipose tissue indicate obesity or overweight. Obesity is known to be a worldwide epidemic that adversely affects health and longevity. The various conditions associated with obesity include:

Metabolic syndrome

Metabolic syndrome is a collection of conditions that increase your risk for heart disease, diabetes, and stroke. To be diagnosed with metabolic syndrome, you must have at least three of the following conditions:

• large waist size
• high levels of triglycerides in your blood
• high blood pressure
• high level of blood glucose when fasting
• low level of HDL cholesterol, the “good” cholesterol, in your blood

Fatty liver diseases

Fatty liver diseases develop when fat builds up in your liver, which can lead to severe liver damage, cirrhosis, or even liver failure. These diseases include nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). People who have insulin resistance, unhealthy levels of fat in the blood, metabolic syndrome, type 2 diabetes, and certain genes can also develop NAFLD and NASH.

Some cancers

Men who are overweight or obese are susceptible to developing cancers of the colon, rectum, and prostate. Women who are overweight or obese are prone to cancers of the breast, the lining of the uterus , and the gallbladder.

Sleep apnea

Obesity is a common cause of sleep apnea in adults. If you are overweight or obese, you may have more fat stored around your neck, making the airway smaller. A smaller airway can make breathing difficult or cause snoring. 

Asthma

Asthma is a long-term condition that affects the airways in your lungs and leads to narrowing of the airways. Obesity can increase your risk of developing asthma, worsen your symptoms, and make it challenging to manage the condition.

Osteoarthritis

Osteoarthritis is a common condition that causes pain, swelling, stiffness, and decreased motion in your joints. Obesity puts increased pressure on your joints and cartilage. Moreover, excess body fat causes your body to produce higher levels of substances that cause inflammation, which increases the risk for osteoarthritis.

Low values on the body composition scan

Low values on the body composition scan indicate sarcopenia. Sarcopenia is a condition where there is a progressive, generalised loss of muscle strength, accompanied by a quantitative or qualitative loss of skeletal muscle mass. This is linked to poor clinical outcomes, including a loss of physical independence, reduced quality of life, and an increased risk of falls/fractures and death. Low muscle strength indicates probable sarcopenia, and the diagnosis is confirmed by decreased quality or quantity of muscle mass. Loss of muscle performance indicates severe sarcopenia.

Sarcopenia can be primary or secondary. While primary sarcopenia is associated with the ageing process, secondary sarcopenia is associated with triggers such as:

• Inadequate protein intake
• Gut-associated malabsorption disorders
• Critical illness
• Cancer, and various chronic diseases (e.g., chronic kidney disease, chronic obstructive pulmonary disease, and severe congestive heart failure)

What can you do for out-of-range results on the body composition scan?

The increase in different values on the body composition scan needs to be addressed. You will need to lose weight for optimal health. You can follow the CQE approach: Cut calories, choose Quality foods, and Exercise daily for weight loss.

• Diet: Cut down on foods containing saturated fats, trans fat, cholesterol, added refined sugars and include whole grains, vegetables, lean proteins, and low-fat dairy products 
• Eating habits: Cutting back on portion sizes helps reduce calories. You are more likely to overeat while watching TV or while taking free treats at work
• Exercise: Engage in 2-5 hours of exercise per week. Exercises include walking, jogging, biking, swimming, and water aerobics
• Self-monitoring: You can monitor your diet and activity levels with various apps.
• Medications/supplements: Consult with your healthcare provider about the suitability of starting medications or supplements for weight loss.
• Surgery: For people who have severe obesity, weight-loss surgery—also called metabolic and bariatric surgery may be an option

When your values on the body composition scan are lower than normal, consult with your doctor to explore the possible causes.

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Sources

1. Kim TN. Use of dual-energy x-ray absorptiometry for body composition in chronic disease management. Cardiovasc Prev Pharmacother. 2024;6(4):128-134.

2. Holmes CJ, Racette SB. The Utility of Body Composition Assessment in Nutrition and Clinical Practice: An Overview of Current Methodology. Nutrients. 2021;13(8):2493. Published 2021 Jul 22. doi:10.3390/nu13082493

3. Chaves LGCM, Gonçalves TJM, Bitencourt AGV, Rstom RA, Pereira TR, Velludo SF. Assessment of body composition by whole-body densitometry: what radiologists should know. Radiol Bras. 2022;55(5):305-311. doi:10.1590/0100-3984.2021.0155-en

4. National Institute of Diabetes and Digestive and Kidney diseases – Health risks of overweight and obesity.

https://www.niddk.nih.gov/health-information/weight-management/adult-overweight-obesity/health-risks.

5. The nutrition source-body fat.

https://nutritionsource.hsph.harvard.edu/healthy-weight/measuring-fat.

6. Australian Institute of sports: Practitioner best practice guidelines.

https://www.ais.gov.au/__data/assets/pdf_file/0004/1095061/Practitioner-Best-Practice-Guidelines-for-DXA-Assessment-of-Body-Composition.pdf

7. UC Davis Health - DXA body composition analysis.

https://health.ucdavis.edu/sports-medicine/resources/dxa-info