About Body Composition

What is body composition?

The human body is composed of a variety of different tissues.  The 'lean' tissues such as muscle, organs and bone are metabolically active, while adipose, or fat tissue, is not.  Weight scales can't determine the lean-to-fat ratio so an individual can be ‘over-weight’ but not necessarily ‘over-fat’.  Height-weight charts are therefore not always a good indication of a person's ideal weight for optimal health. Body composition measurements allow us to determine accurately the different proportions of our body: Fat, lean tissue (like muscle) and bone.

Is body composition important?

Our body composition is one of the most important indicators of our health.  Poor body composition, specifically too much body fat in the wrong places, contributes to the development of diseases such as diabetes, high blood pressure, obesity, some cancers and heart disease.  Central abdominal fat, known as visceral adipose tissue (VAT), in particular has been shown to be a useful predictor of future diabetes, heart attack and stroke.

What should body fat percentage be?

Body fat varies in men and women, and with age.  However, there are some standards.  The minimum body fat recommended for good health is about 7% for males and 20% for females.  Just as too little body fat is unhealthy, too much body fat also has harmful effects.  Once men exceed approximately 25% and women exceed approximately 35% fat, there is a definite correlation with illness and disease; including heart disease and type 2 diabetes.

How do I find out my body composition?

The best and most widely accepted test is a DXA (or DEXA scan, Dual Energy X-ray Absorptiometry) which measures body composition using low dose X-rays.  DXA measures whole body fat as well as regional fat, including central abdominal fat, as well as lean tissue.

Can I change my body composition?

To increase or decrease your percent body fat you need to create the right balance between the calories you consume and the calories you burn.  Aerobic exercise is a very effective way to decrease body fat, however, you must combine strength training in order to maintain or gain muscle mass and tone.  Advice from exercise professionals, dieticians and/or your doctor (particularly in the older patient) may assist.

Is a dietary assessment useful?

Individuals who wish to lose weight or modify their body composition can benefit from an assessment of their nutrient and caloric intake which may differ significantly from their perceived intake.  This information is useful  in making diet and lifestyle changes to reduce the risk of developing various diseases.

Can children be scanned?

Even though the radiation dose is very low, Chatswood Densitometry has a DXA imaging policy by which only individuals over the age of 18 years will be scanned.  Exceptions to this may be considered on an individual basis following discussions with treating health professionals and parents.  In these cases you will need a referral from your referring practitioner if clinically indicated.